Modifications for the Yaesu FT-817

Picture(s) of Yaesu - FT-817

02-01-2001 Battery mod for ft-817 English language
20-01-2001 Extended TX for FT-817 English language
18-03-2001 Hidden menu for YAESU FT-817 English language
07-04-2001 FT-817 Tips German language
23-05-2001 YAESU FT-817 Servicepoints English language
10-07-2001 Improvement of the ALC - better modulation and throughput English language
10-07-2001 Improvement of the optional microphone MH-36 E8J with DTMF English language
28-08-2001 AGC modification for FT-817 English language
08-12-2001 HF Clipper für Einbau in das Handmikrofon des Yaesu FT-817 German language
05-01-2002 FT-817 paddle modification, very useful for CW ops. English language
08-01-2002 Yaesu FT-817 CW Filter Installation English language
08-01-2002 Other Observations/Comments on the FT-817 BY AD6A English language
02-02-2002 FT-817 RX-LED disconnect English language
01-04-2002 FT-817 TX frequency / Region setting English language
16-05-2002 Et enkelt front løft til FT-817 Norway language
08-06-2002 FT-817 Mod. 2 Collins Filter (CW AND SSB) English language
31-08-2002 FT-817 10 Watts output English language
06-10-2002 Yaesu FT-817 CAT interface English language
12-10-2002 Yaesu FT-817 Mod/Fix English language
04-01-2003 KA7OEI FT-817 page English language
06-04-2003 Improvement of stock mic for FT-817 English language
09-04-2003 FT-817 FM mod improvement (more basses) English language


02-01-2001 add a comment
Battery mod for ft-817

Yaesu folks want you to buy the 9.6 vdc battery pack and do not recommend you attempt to charge batts. from the included "stock" alkaline pack.
They have even rigged the pack so it will not charge. Poking around with a VOM I discovered that there is a way to make the alkaline pack charge. Pull out the pack and peel the tape off of the end with the wires.
You will find 2 red wires, 2 black wires and a green wire. cut and insulate the green wire. Put Nicads or NiMh Batteries in the the pack and set up the charge time circut. I have done this with no problem. This keeps you from breaking the bank buying alkaline cells and give you portable batt. power.

Two words of caution:

As with all mods, the warranty is affected, do so at your own risk.

By during this mod you have now disabled the protection feature and can re-charge alkaline batts.
This could be dangerous and careful not to do that. Of course with this mod, you will have little reason to use alkaline cells.

Enjoy. I look forward to hearing about other ft-817 mods for this nifty little rig.

Date: 09-04-2001 User comment From: Bill - WA6CCA
Subject: Install fuse.


When you do the "green wire mod" on the FT-817 to permit charging of internal NiMH or NiCad batteries, it's very important to install fuse protection or you could ruin your motherboard (a VERY expensive mistake).

Perhaps the easiest way is to install a 2-3 amp Pico fuse in line with the positive (red) wires leading to the battery pack. Better still, put another Pico fuse in line with the negative (green) wires also.


Date: 07-06-2002 User comment From: Greg, N6RDE
Subject: Fuses question

Hi Bill: where do you get the fuses? I am in Sacramento area. Any suggestions online. Is the concern that when charging the nimih’s that it will overcharge. Or that the fuses in some way limit the current when operating the the 817. I’m thinking it is to keep stray voltage from the motherboard. I am not sure and would appreciate your comments.


Date: 14-06-2002 User comment From: andy - do6oal
Subject: NC-Akkus aufladen...

die NC-Akkus in das Batteriefach legen, das GRÜNE kabel trennen und schon werden die Akkus geladen. Hab selber getestet und funzt...

Date: 28-09-2002 User comment From: Bob G4APV
Subject: Green wire mod

There is no need to cut the green wire to get the alkaline pack to charge. Split the white connector and then on the pack connector carefully lift the white plastic tongue that stops the green wire pulling out of the connector. It will then pull out. This way you can push it back later and no one will ever know!


This modification has been read 25350 times.

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20-01-2001 add a comment
Extended TX for FT-817

  1. Remove the front panel

  2. Look down on the back of front panel, with the VFO knob just left of center. Look at the jumper locations just above the VFO knob on the circut board. Solder the first four jumpers and remove the solder at location five.

  3. Reassemble the radio, and reset the cpu by pressing the HOME and the power button.

This will extend the xmit freqs. on HF,VHF and UHF

Another mod.

The following Yeasu FT-817 frequency expansion modification is identical to the version provided by the manufacturer for MARS/CAP application.

  1. Remove any power or battery from the Radio.

  2. Remove the 14 screws holding the top and bottom covers to the radio.

  3. Remove the battery cover latch.

  4. Remove the covers.

  5. Remove the BNC retaining nut.

  6. Carefully lift the 4 plastic tabs holding the front panel to the chassis and slightly move the front panel forward.

  7. Disconnect the ribbon cable that connects the chassis and the front panel.

  8. Remove the jumper at location on Front Panel (J4005)

  9. Press and hold the "VFO/MR" key and the "F" key while turning on the radio.

  10. Reassemble the radio.

Note: The manufacturer states that "this modification opens up transmit coverage for MARS/CAP ONLY!" Other published modifications also have the user bridge the "first four jumpers". The difference between the two modification schemes has not been tested by the author.

Proceed at your own risk.


Date: 22-10-2001 User comment From: webmaster
Subject: Important about the photo.!

I have not this radio by myself, so i can verify the modification by myself.

About the photo, i have received messages that telling me that the numbers order should be reverse, so that the smallest number (1) should start from the left side, and not the right side.

Following has reported that the BLUE numbering is correct:
Rob Boux (ve4rrb) boux(a)
Tim Salisbury (KD7MBN) timsalisbury(a)
Jim (W7LS) w7ls(a)

Date: 29-12-2001 User comment From: Andrew VK3EGR
Subject: The BLUE numbers are correct .

I tried the extended TX modification using the blue numbers in the photo ie : where jumper 1 is at the left, and it worked. I found, tho, that you have to hold down the F and V/M buttons together whilst powering up the FT-817 for the changes to take effect.

Date: 15-01-2002 User comment From: Igor OM3CUG
Subject: The BLUE numbers are correct

I tried the extended TX modification using the blue numbers in the photo, where jumper 1 is at the left it works. Reset CPU: hold down the F and V/M buttons together whilst powering up the FT-817 for the changes to take effect. 73 Igor OM3CUG

Date: 22-02-2002 User comment From: 9M2ZC
Subject: Tx freqs

What are the new TX freqs. after the mods for all the specified bands??

Date: 22-02-2002 User comment From: Lars SM4IVE
Subject: Extended TX

Well after doing the mod & soldering the pos 1,2,3,4 and reseting the unit my ARS funtion disapered?
Have any one else noticed this.
greetings Lars

Date: 23-02-2002 User comment From: Mike KB3HND
Subject: Marine Band Capability?

Will this TX modification permit the 817 to transmit on marine band frequencies? We would like to use the transceiver as a back up on our sailboat.

Date: 02-03-2002 User comment From: Bill-WD5INA
Subject: Verifed Jumper IDs

I rang out the jumpers to the foil traces on my FT-817 and found that the red numbers of the photo above agree with the schematic included with my radio. J4001 ~ J4009 follow the numbering in red from 1 ~ 9. This then changes the four (left hand) jumper IDs to 6 ~ 9 (J4006 ~ J4009) that should be shorted in order to open the transmit range of this rig.

My radio was a type BY3 (purchased in Singapore Feb. 2002). When I opened it up, jumper five (J4005) was not soldered but position 6&8 (J4006 & J4008)were. I soldered position 7&9 (J4007 & J4009)and checked out the rig. This mod opened up the transmit capability just as the posted mods above stated. No negative results were noted.

This modification worked on my rig, I take no credit or blame for your results.

Date: 27-03-2002 User comment From: Steve G8SBF
Subject: Extended TX FT817

I have a UK purchased FT817 and will travel to the USA soon where they use a different 70cm and 2m allocations. I want to modify the UHF Tx band limits to also cover 440-450MHz and 144- 148MHz as well as the 430-440MHz allocation here. Does anyone know whether the modification listed expands the UHF transmit to cover 430-450MHz and whether modifying the rig affects any other features. The US model has a front panel RF gain control - does the mod affect the function of this knob?

Thanks, Steve G8SBF

Date: 24-04-2002 User comment From: EA4DCK
Subject: How to extend TX below 1.8 mhz. in FT-817 yaesu?

How to extend TX. below 1.8 Mhz. in FT-817 ( yaesu ). Send an E-mail to me! and Thanks !.

Date: 20-06-2002 User comment From: Jason
Subject: Marine band

Does anyone,know how to expand(at least to receive) on the marine band frequencies on the FT-817?

Please E-mail me. Thank you and 73

Date: 16-07-2002 User comment From: N3KHI
Subject: 817 BLUE number mod

Please use the BLUE numbers on the US version of the 817 for increased transmit. That is what worked for me.

Date: 11-08-2002 User comment From: Ian Keyser, G3ROO
Subject: FT817 solder bolb mod

I've done the mod and fine on HF but on VHF still restricted to amateur bands.... I wanted Tx on airband! Any ideas?

Date: 02-09-2002 User comment From: Mike G3TSO/KD3CL
Subject: Jumper Numbers

I have modified the 817 for UK 5MHz operation and have found that the RED set of numbers is correct. This also agrees with Yaesu's own US modification sheet. For full coverage, bridge J4007, 8 and 9. If you also bridge J4006 the coverage remains the same. My 817 is a US Version and was originally bridged 5,6 and 7.
Full TX coverage is:

1.8 - 33 Mhz
33 - 56 MHz
140 - 154 MHz
420 - 470 MHz

Date: 25-09-2002 User comment From: Bill
Subject: Any mods ft-817 to rec. weather bands

Looking for a mod to open up rec on the ft-817 for the weather band.

Date: 15-10-2002 User comment From: Johnny Siu VR2XMC
Subject: frequency expansion

I posted my workings on the frequency expanison in the FT817 reflector and received many enquiries. Perhaps, I would like to repeat here on what I did:

1.I follow the RED numbers in the previous messages;
2.Counting from the left, I bridged all the solder pads 9,8,7 and 6;
3.Solder pads 5,4,3,2, and 1 at the right remain opened
4.After the modification, the rig was reset by holding V/M and F and powered on.


Johnny Siu VR2XMC
the Lot no. of my fig is 58 manufactured in Sept 2002

Date: 27-10-2002 User comment From: Gene Brewer KI6LO
Subject: Initial config different than writeup

I have a US version of FT817 purchased NEW from AES Las Vegas (s/n 1K440097) and when I checked the original config of the solder bridges, I found (using the BLUE numbers) 3, 4 and 5 solder bridged and the rest are OPEN.

My question referring to the original post, Is do I unsolder 3 and 4 also along with 5 and solder 6 thru 9? Or do I need to leave 3 and 4 as they are now?

I'm sure some else has seen this config and made the mod. Suggestions???

Thanks Gene KI6LO

Date: 14-12-2002 User comment From: Gene Vantreese WD5FDL
Subject: tx mod

i don't know penned these instrutions on how to do this tx mod but I do know that they Dont know how to be a technical writer "assumsion is the of whatever" i left out the explicatives to be nice.the aurthor says to carefully remove the ribbon cable but he does not say how or how to put it back and he assumes we all know how.Problem is there billions of connectors " to exaggerate but you know what i mean" every engineer wants to design things his own way amd there are millions of engineers. so why dont you clue us non engineer types
in on how to open the connector for the ribbon cable> if you want i will ... it opens like the Trunk of your car and its very very brittal VERY BRITTAL. now i have to send my radio in for repair because i have Large hands and cant see very good and somebody does not know how to write technical articals

Date: 17-12-2002 User comment From: KA7QOR
Subject: FT-817 Asia version

I purchased my FT-817 from a Hong Kong dealer located in Guangzhou China. According to the red numbers in the picture, my Asian version comes with jumpers 8 and 6 soldered and 5 is open. I soldered jumpers 9 and 7 together then reset the CPU holding the F and V/M keys when I powered up the rig. It worked fine for me, I now have general coverage transmit with no side effects. By the way, Im guessing that jumper five is for the Alaska emergency frequency as it is not a feature of the Asian model and jumper five was left open in the factory.

Date: 12-01-2003 User comment From: KC0GAN
Subject: ARS logic reversed after mod

I performed the mod on my USA FT-817 rig, leaving it exactly as shown in the picture above, where the 4 jumpers on the left are shown soldered.

After resetting, all memories were erased. I then reloaded the memories using the Yaesu software from RT Systems. The memories reloaded correctly.

However I noticed the Auto Repeater Shift (ARS) function appeared to no longer be working. This may be the same problem SM4IVE mentioned in an earlier comment.

I then discovered that the ARS can still work, however the enabling logic is now reversed. If you want ARS to be ON for the 144 and 430 bands, you must turn ARS OFF. The ARS band logic is now backwards, so when I select to disable it for those bands, the ARS works fine.

73, Doug

Date: 22-01-2003 User comment From: Andrew Lenton G8 UUG & M3UUG
Subject: Extended TX for FT 817

I found the numbering in red to work, on my FT 817, there is no BNC nut to undo, the front panel, unclips, remembering to disconnect the ribbon cable first! 73's Andrew G8 UUG

Date: 23-01-2003 User comment From: anonymous
Subject: Mode in opened up state

Before I do the mod on my set, is it confirmed that all modes are still available on any frequency. I mean for example FM and SSB on CB 27Mhz band?

Date: 02-02-2003 User comment From: Ron the living ham legend
Subject: I smoked my radio

I foolowed the derectshuns as best as could but myu radio smoked and cought fire after i pluggen in the wall.

Date: 09-02-2003 User comment From: N8CVW
Subject: FT-817 xmit mod results

FT-817 mods, (SN? 1E3xxxxx)

1st try: (BLUE numbering) desolder #5, solder 6, 7, 8, 9; counting from left (=1)

a- 50 MHz band no longer present
b- 2m band limited to 144-148 access
c- squelch control inverted, cw=open, ccw= closed
d- ARS not functional in either on or off settings, both 2m & 70cm bands
e- no power output on xmit

2nd try: (RED numbering) desolder #5, solder 1, 2; counting from left (=1) (note: 3 & 4 already soldered)

this works! (except ARS, must use RPT selection MENU4 to select offset operation)

rig now transmits:


(does not xmit: <1.8MHz, 76-108, 108-137, 137-140)

Date: 24-03-2003 User comment From: buggy g
Subject: ft-817 mods

I see alot of people doin the mods on the ft-817, and have problems. My suggestion would be this. If YAESU wanted you to to transmit out of band, have better audio, charge any battery in the rig, they would be seling the rig with this done.

I even see a mod for 10-15W power increase. It is a QRP radio folk's!!!!

Date: 03-05-2003 User comment From: n0mhs
Subject: no problems

Hey, buggy;

Why don't you "buggy off", OK? Coming onto a mods site, and telling people not to do the mods is IDIOTIC. What are you, some kind of WEIRDO?


This modification has been read 38169 times.

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18-03-2001 add a comment
Hidden menu for YAESU FT-817
Author: Noel - ON7XV -

Just push and hold A, B and C simultaniously while putting the rig on, and you're in the hidden menu with about 57 settings.

Number 5 for the 2 meterband will increase sensitivity while increasing he numbers; Default setting / 79.

To leave the menu just push and holf the F function just as the "ignition" switch will do .

It works...
Noel - ON7XV - Belgium

Date: 07-04-2002 User comment From: FRANK IK5RNL

73 es cul fm IK5RNL frank


This modification has been read 27718 times.

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07-04-2001 add a comment
FT-817 Tips
Author: Volker -

Hallo liebe FT-817 Fans,

ich bin seit kurzem zufriedener Besitzer eines solchen Gerätes und möchte hier ein paar Tips loswerden, die entweder aus dem Internet stammen oder auf meiner eigenen Meinung beruhen.

Bevor es ins Eingemachte geht eine wichtige Anmerkung-ein besonderer Schwachpunkt ist das Batteriefach:

Beim Herausnehmen der Batterien ist darauf zu achten, daß diese nicht den Bodendeckel berühren. Dieser ist an der Seite, wo die Batterien darunter verschwinden, extrem schlecht entgratet. Es gibt leicht Kurzschlüsse nach Masse, wenn die Plastikhülle der Batterien beschädigt wird.
Dies ist besonders unangenehm bei der Bestückung mit Accus, weil diese einen "guten" Kurzschlußstrom liefern. Ich empfehle eine starke Folie dazwischen zu legen.

Grundsätzlich sind VOR dem Öffnen des Gehäuses auf jeden Fall die Battereien zu entfernen und eine externe Spannungsversorgung abzuklemmen!!!

Tip1- Betrieb mit Accus:

Das Batteriefach kann natürlich auch mit Accus bestückt werden. Wer die Accus nicht extern, sondern mit dem internen Timer laden möchte muß den grünen Draht, der zum Batteriefach führt irgendwo unterbrechen und die Enden isolieren, damit ein Accu erkannt wird. Wer wegen der Garantie eine reversible Änderung vorzieht kann im Stecker den entsprechenden Pin mit etwas Geschick und einer Nadel herausholen.
Weil der Yaesu-Accu nur 1000mAh hat und es für weniger Geld bereits 1600mAh NiHy Accus gibt kann ich das nur empfehlen! Beim Laden der Accus ist zu beachten, daß eine geeignete Ladezeit im Menü gewählt wird. Der Ladestrom ist etwa 170 mA.
Nach Ladeende fließt ein Erhaltestrom von 15 mA, es dürfen also keine Trockenbatterien mehr eingelegt werden wenn eine extere Spannungsversorgung erfolgt!!!

Tip2- Erweiterung des TX Frequenzbereiches zum Betrieb mit Transvertern

Hierzu ist zu sagen, daß im Internet Meinungen existieren, daß sich nicht alle FT-817 erweitern lassen- dies scheint zumindest bei den für den japanischen Markt gebauten zu stimmen. Mein Gerät, Serien-Nr. 1C20nnnn, mit CE-Zeichen, war in der Hinsicht freundlicher.

Den Lieferzustand habe ich nicht exakt in Erinnerung, auf KW / 6m waren es die DL Amateurbereiche und auf VHF / UHF erheblich mehr. Nach der u.a. Änderung ergab sich folgendes Bild:

TX: 1,8 - 33 MHz überall max. 5 Watt

TX: 33-56 MHz, 140-154 MHz, 420-470 MHz hier fällt außerhalb der USA-Amateurbänder die Leistung ab.

Die ARS-Funktion ist außer Betrieb, was (mich) aber nicht stört- man kann den Repeaterbetrieb und die Shift weiterhin von Hand einstellen. Der 1750 Hz Tonruf bleibt erhalten.

Nun zur Änderung:
Batterien entfernen (s.o.)
Alle Schrauben von Bodenblech und Deckel (nicht die direkt am Lautsprecher) lösen. Dann die beiden Bleche entfernen. Hierbei bitte beim Bodenblech den Riegel für das Batteriefach im Auge behalten- die zwei Federn sind schnell weggesprungen!

Wenn man schon mal die Deckel ab hat kann man auch mit einer Feile den Grat beim Batteriefach entfernen...

Das Flachbandkabel zur Frontplatte lösen, hierzu muß dessen Verschluß an der Platine vorsichtig hochgeklappt werden. Die Frontplatte nach vorne lösen, dazu die vier Plastikklemmen anheben.

Die Reihe mit den neun Lötbrücken ist leicht zu finden. Bei mir waren sie folgendermaßen gebrückt: =0=0=====

0 heißt dabei geschlossen und = offen

Mit: 0000===== ergibt sich die oben beschriebene Variante.

Vorsicht beim Löten, etwas Erfahrung sollte man schon haben um keine unerwünschten Kurzschlüsse zu produzieren!

Ganz wichtig- Nach dem Zusamenbau muß unbedingt der folgende Reset durchgeführt werden:

Die F und V/M Tasten gleichzeitig festhalten und den FT-817 einschalten. Dabei werden leider alle Speicher und Einstellungen gelöscht !

So, nun noch eine Frage zum Schluß:
Der Ft-817 ist ja angeblich "PR-tauglich", hat schon mal wer die Umschalt-zeiten (TXDelay) gemessen- sind sie wirklich für 9600Bd in einer vernünftigen Größenordung ???

73 de Volker in Hannover,
e-mail: DL6OBU @ QSL.NET
19.03.2001, 17:32:05 (Local Time)

Date: 07-08-2002 User comment From: IV3DXW Claudio
Subject: Translation in english

Any DL OM can kinldy translate in english?
tnx vy much!



This modification has been read 23573 times.

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23-05-2001 add a comment
YAESU FT-817 Servicepoints
Author: DL5GBL

(push A/B/C synchron and start device)

1;HF1RXG RX GAIN;1.8MHz;181;
3;HF3RXG RX GAIN;21MHz;123;
4;50MRXG RX GAIN;50MHz;66;
6;UHFRXG RX GAIN;430MHz;117;
7;SSB-S9 SSB S-Meter;S9;70;
8;SSB-FS SSB S-Meter;FS;59;
9;FM-S9 FM S-Meter;S9;76;
10;FM-FS FM S-Meter;FS;109;
11;DISC-L FM Center;Meter;35;
12;DISC-H FM Center;Meter;69;
13;FM-TH1 FM;Squelch;82;
14;FM-TH2 FM;Squelch;82;
15;FM-TI1 FM;Squelch;14;
16;FM-TI2 FM Squelch;14;
17;VCC Power Supply;Voltage;138;
18;HF1-IC Over-current Protection;1.8MHz;111;
19;HF2-IC Over-current Protection;7MHz;116;
20;HF3-IC Over-current Protection;21MHz;111;
21;50M-IC Over-current Protection;50MHz;113;
22;VHF-IC Over-current Protection;144MHz;126;
23;UHF-IC Over-current Protection;430MHz;113;
24;HF1-HI RF Power HI;1.8MHz;116;
25;HF1-L3 RF Power L3;1.8MHz;67;
26;HF1-L2 RF Power L2;1.8MHz;21;
27;HF1-L1 RF Power L1;1.8MHz;4;
28;HF2-HI RF Power HI;7MHz;119;
29;HF2-L3 RF Power L3;7MHz;65;
30;HF2-L2 RF Power L2;7MHz;21;
31;HF2-L1 RF Power L1;7MHz;3;
32;HF3-HI RF Power HI;21MHz;117;
33;HF3-L3 RF Power L3;21MHz;63;
34;HF3-L2 RF Power L2,21MHz,20;
35;HF3-L1 RF Power L1;21MHz;2;
36;50M-HI RF Power HI;50MHz;115;
37;50M-L3 RF Power L3;50MHz;64;
38;50M-L2 RF Power L2;50MHz;23;
39;50M-L1 RF Power L1;50MHz;1;
40;VHF-HI RF Power HI;144MHz;140;
41;VHF-L3 RF Power L3;144MHz;93;
42;VHF-L2 RF Power L2;144MHz;28;
43;VHF-L1 RF Power L1;144MHz;12;
44;UHF-HI RF Power HI;430MHz;103;
45;UHF-L3 RF Power L3;430MHz;68;
46;UHF-L2 RF Power L2;430MHz;21;
47;UHF-L1 RF Power L1;430MHz;9;
48;HF1TXG TX Gain;1.8MHz;67;
49;HF2TXG TX Gain;7MHz;62;
50;HF3TXG TX Gain;21MHz;67;
51;50MTXG TX Gain;50MHz;89;
52;VHFTXG TX Gain;144MHz;79;
53;UHFTXG TX Gain;430MHz;69;
54;HF1POM Power Meter Sensitivity;1.8MHz;71;
55;HF2POM Power Meter Sensitivity;7MHz;72;
56;HF3POM Power Meter Sensitivity;21MHz;71;
57;50MPOM Power Meter Sensitivity;50MHz;70;
58;VHFPOM Power Meter Sensitivity;144MHz;83;
59;UHFPOM Power Meter Sensitivity;430MHz;64;
60;ALC1-M ALC;Meter;204;
61;ALC-M ALC;Meter;125;
62;HF1-RV Reverse;ALC;1.8MHz;13;
63;HF2-RV Reverse;ALC;7MHz;11;
64;HF3-RV Reverse;ALC;21MHz;21;
65;50M-RV Reverse;ALC;50MHz;15;
66;VHF-RV Reverse;ALC;144MHz;7;
67;UHF-RV Reverse;ALC;430MHz;28;
68;CW-CAR Carrier;Level;CW;252;
69;AM-CAR Carrier;Level;AM;210;
75;LSB-CP;SSB;Carrier Point;-19;
76;USB-CP;SSB;Carrier Point;-20;

Proceed at your own risk.

73 from ron, dl5gbl

Date: 19-07-2002 User comment From: Manuel; DL2MAN
Subject: Voltage alignment successfull !!!

My 817 showed 15V @ the Input Voltage of 13,6 V. So i pushed the 3 Buttons while powering up. At Menu Number 17 I chose 136 and Voila, 13,6 V is displayed @ 13,6 V !!! Thank you for this detailed Service Menu Overview.

Date: 22-09-2002 User comment From: Paul
Subject: Defaulf Settings

Just a quick question. Are the values quoted above, the default values or modified values? and Is there anyway of resetting the values to 'default' without going through each one in turn.


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10-07-2001 add a comment
Improvement of the ALC - better modulation and throughput
Author: Andreas Duessler -

Hi ladies and gents,

The FT-817 is a lovely rig, isn´t it? This is a radio one must have - without special reasons. But anyway, when I got the radio one week ago, I started to test it against excisting others. (like TS-870). Everything was quite okay, but the output in SSB is not reaching the 5W-mark, even when the CW-tone and in FM the rig runs on specified power. I walked through the curcuit-diagram and found the reason. The capacitor C1113 on the mainboard is too small. This has to be changed to bigger values. In my case it´s now 470 uF insted of former 1uF.

To find the place inside the rig .... boy! This took some time. But after locating the place, it´s now easy to descibe:

Open the upper side (where the loudspeaker fits) and locate the red jack on the rear side. Inside a flatband-cable comes up and is connected. Right beside this cable you find C1113, but it´s not labeled. But anyhow, look for the pictures taken and I´m sure you find the place. The new C is visible in the lower right corner of the picture (big and black) I removed the original C from the board before - but it´s still not necessary.

After finalizing, close the rig and test the output in SSB in comparison to FM and CW. The throughput is now there. And believe me, you get better voicereports. And running qrp - it´s sometimes the needed peace of junk !

Click to enlarge (335 Kb)

Click to enlarge (92 Kb)

Best wishes and good luck !


Date: 20-04-2002 User comment From: John K7RO
Subject: FT817 ALC mod 1uF to 47uF C1113


I looked into the ALC mod you posted for the FT817. You changed a 1uF cap to 470uF

I entered the circuit into a simulator and got these waveforms. It appears this mod lengthens the ALC "release time". Check out the simulate ALC output voltage waveforms below

It appears the stock "ALC release time" is 500mSec+ It looks like the mod would increase this alot. Does this make sense to you. I thought a short release time would raise the average power? It works so I must be missing something....

In the schematic below V1 simulates a 500mS pulse coming from the Forward detector. The ALC drives the dual gate VHF MOSFET to provide gain control. I set up V1 to simulate a 500mS pulse coming from the forward detector. It repeats every 2 seconds The ALC levels at the MOSFET gate are; 4V for maximum gain and 1V sets minimum gain.

The green trace is stock FT817 the blue trace is with 1000uF.

Date: 09-02-2003 User comment From: Alex RV3ALM
Subject: ALC mod

Hi! I change 1mF capacitor to 470mF. SSB power o/p is real 5 w. But i found delay 1-2min. when i push PTT and FR power go-go to hight level very slowly. I install 4.7 mF. Now it"s o"key. WBR.


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10-07-2001 add a comment
Improvement of the optional microphone MH-36 E8J with DTMF
Author: Andreas Duessler -

Hi ladies and gents,

The original microphone works good, but I tested also the DTMF-microphone, which is available now. It sounds really bad, and that wondered me, because a small electret-microphone is inside. But after opening the mic, the reason was easealy located. The necessary DC-voltage, comes to the microphone via a small resistor. The value of this resistor is by far too low - replace it to a value near 10 Kohms.

Now the microphone is better than the original one and has all these options like DTMF and it´s backlighted !

The picture should help to locate the small resistor. The new one is a traditional one ( I had no SMD-resistor )

It looks bad, but it works the way the new microphone is very sensitive now...go down to values of 20 (original is 50 !) in the setup of the FT-817 specially in SSB.

Good luck !


Date: 01-12-2002 User comment From: GØOXZ
Subject: What about the FT-100 mic?

Does this mod apply equally to the MH-36B6JS as supplied with the FT-100/D?

The recognised mod elsewhere on this website is to remove a foam rubber sound 'baffle' from the electret mic insert, no electronic mod required... which would work better I wonder?


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28-08-2001 add a comment
AGC modification for FT-817
Author: Andreas Duessler -

Hi YL´s XYL´s and OM´s,

Regarding the AGC (RX) of the FT817 I got some questions from some users. The dynamic of the AGC-regulation isn´t really nice researched. If you use the rig specially on 40m and/or 80m where often high signal strenths are present, the RX sounds like the AGC is switched completely "off". If using with small signal amplitudes it sounds much better. This seems to be a general problem of the FT817.

To fix this is only recommened for let me call it "advanced users". The rig has to be opended on the upper side (where the loudspeaker fits). Now you remove all connected cables from the visible main board and all srews. After this you can remove the board.

Please turn the board to the soldered side and locate C1324, which is nearest to the connected data-cable going to the user-interface (front panel).

Near this C you find R1305. Original values are 1 K and 2,2uF.

Now the mod:

Please put 10 Ohms in parallel with R1305 and 10uF parallel to C1324.

Please be carefull in doing this, the SMD-parts are very small !


In my case, I had no SMD-C available (and I didn´t want to use Tantal-C´s), therefor I connected the 10uF via cable to the upper side of the main board. It´s not looking nice, but nevertheless it´s working.
Values over 10uF (470uF) are better, but the S-meter stand still at approx. S6-7 afterwards. It´s not recommended to go over 10uF.

Good luck and again: be carefull!!!

Thanks for reading this and I apologize for the picture, which is not exactly focused. (I saw it too late...)

Click to enlarge (83 Kb) Click to enlarge (115 Kb)


Date: 12-04-2003 User comment From: Jochen Heilemann (DG2IAQ)
Subject: How to fasten the s-meter !?

How to fasten up only the s-meter after this mod ?

I think reducing C1331 or C1334 for FM should be right ?? (above the FM-DET-IC Q1069, BA4116FV). But how to do this for SSB ?

Any suggestions ?

Jochen Heilemann (DG2IAQ)


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08-12-2001 add a comment
HF Clipper für Einbau in das Handmikrofon des Yaesu FT-817
Author: Joachim Münch DF4ZS -

Joachim Münch DF4ZS - 7 Dezember 2001

Vorweg, für Schäden die durch den Umbau verursacht werden übernehme ich keine Haftung. Bei mir und einigen OM´s funktioniert der HF-Clipper bestens und bringt so an die 10 dB. Der Einbau in das Mikrofongehäuse erfolgt durch Austausch der dynamischen Mikrofonkapsel. Richtet man sich nach der unten stehenden Einbauanweisung kann nichts schief gehen, sorgfältiges löten voraus gesetzt. Das Clippermodul eignet sich auch für den Einbau in andere Handmikrofone. Ab einer Versorgungsspannung größer 9 Volt ist die Spannungsversorgung über einen 78L06 Spannungsregler dem Modul zu zuführen.

Der Einbau.

Mit einem Kreuzschlitzdreher wird der hintere Deckel des Mikrofons gelöst, beiseite gelegt und die Drähte der Mikrofonkapsel abgelötet. Die Platine wird durch lösen von drei Schrauben aus dem Gehäuse genommen, die dynamische Kapsel entfernt und gut verwahrt. In die freigewordene runde Aufnahme der Kapsel wird die Elektret-Kapsel des HF-Clippers gelegt und das Loch mit Dämmwolle für Lautsprecher (Boxenbau) gut bis zum oberen Rand der Mikrofonaufnahme gefüllt. Das Mikrofongehäuse legt man für die folgende Anleitung so, dass die Kabelöffnung zum eigenem Körper zeigt. Die PTT Taste ist nun auf der rechten Seite.
Das Clippermodul legt man mit der Lötseite nach unten über das gefüllte Aufnahmeloch, wobei der seitlich stehende Trimmer (Pegel) des Clippermoduls nach links zeigt. Die Anschlussdrähte des Clippers führt man durch die runde Öffnung der Platine und befestigt diese.
Nach untenstehender Zeichnung werden die Drähte des Moduls angelötet. Mit größter Sorgfalt ist der weiße Draht (Spannungsversorgung) an PIN - 6 zu löten und möglichst mit einer Lupe auf Schluß mit den umliegenden PIN´s zu kontrollieren. Das Clipper-Modul kommt abgeglichen. Der Einbau wäre fertig und die Abdeckung kann  aufgeschraubt werden. Möchte man Clippgrad und Sprache nach eigenen Empfinden einstellen, lokalisiert man die einzelnen Trimmer und justiert diese. Die ALC des FT-817 ist dabei zu beachten.  Die Tendenz der Trimmer jeweils wenn diese nach rechts gedreht werden. BFO-Trimmer erhöht dessen Frequenz ( < > 500 Hz.). Clippgradregler reduziert Clippgrad und Pegeltrimmer minimiert.

Zweitonsignal ungeclippt - stark geclippt - Eintonsignal


Die Funktion eines HF-Clippers habe ich bereits auf meinen Webseiten beschrieben und gehe hier auf einige Besonderheiten des HF-Clippers für den FT-817 ein. Bei der Konstruktion war zu überlegen ob ex- oder intern. Extern wäre kein Problem gewesen, hätte aber den Sinn und Zweck des FT-817 verfremdet. Es kam also nur eine interne Ausführung in Betracht, die dem Charakter des Transceivers entgegenkommt. Weiter war zu überlegen wie ein Umbau ohne bleibende Veränderungen machbar ist, der auch von jedem nicht so geschicktem OM realisiert werden kann.
Die einzige Möglichkeit diesen Überlegungen gerecht zu werden war der Einbau in das Handmikrofon. Um Raum für den Einbau zu schaffen fiel die Wahl auf den Austausch der dynamischen Mikrofonkapsel. Vor einiger Zeit hatte ich bereits einen Mini-Clipper konstruiert der von OM´s die diesen durchweg ungeschirmt in Handmikrofone eingebaut haben, gut beurteilt wurde. Bis 100 Watt sind Probleme mit HF-Einstrahlung nicht bekannt geworden. Diese Ausführung wurde die Basis für den FT-817 HF-Clipper.
Der FT-817 reicht intern über die Mikofonleitung eine stabilisierte Spannung von 5 Volt durch die für das Modul zur Verfügung steht. Einige Bauteile konnten so eingespart werden und anderen Platz machen.  Die Begrenzung des ZF-Signals wurde vom Typ PEP übernommen. Nach den ersten Versuchen in Verbindung mit dem FT-817 stellten sich zwei Nachteile heraus die behoben wurden. Kam das Mikrofon in die Nähe des Transceivergehäuses gab es eine akustische Rückkopplung. Im Empfangsbetrieb wird deshalb das Mikrofon über einen Transistor, von der PTT gesteuert, stumm geschaltet.
Lag die Elektretkapsel lose im Gehäuse war die Modulation bei abgenommener Rückseite des Handmikrofons einwandfrei. Bei montierter Rückseite jedoch stark verfremdet. Die Einbettung der Elektretkapsel in Lautsprecherdämmwolle schaffte Abhilfe.

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Date: 20-07-2002 User comment From: KC7GF
Subject: Translation Please, Please, Please

Could someone with a grasp of German please translate, please, please, please? Thankyou Art

Date: 05-11-2002 User comment From: Joern, DF2HB
Subject: FT-817 HF-Clipper built in microphone

Hi Hams,

I have tried it, and it is far the best I have tried to increase the talk-power of the FT-817.
Loud and clear.
With an external PA of 300W, it works also fine, as long as there are no standing waves on the coax.

vy 73, de Joern, DF2HB

Date: 20-04-2003 User comment From: Jochen Heilemann (DG2IAQ)
Subject: A great improvement !!!

I put the DF4ZS rf speech processor into my MH-31 stock microphone. But I did some other mods. I removed the internal stock mike capacitor (0,33µF) and the resistor (680 ohms). Now I'm using the 1-2-switch to switch between the electret capsule without the clipper (for AM/FM) and with the clipper (for AM/SSB). To use it without the clipper I'm using a 47nF capacitor (0.047mF) from the hot pin of the capsule to one end of the 1-2-switch. This gives a powerful, natural sound.
Probably you must reduce the mic input levels in the menu alignments. I'm using AM(50), SSB (70) and FM (7). The low value for FM depends only on my special FM-modification you can find on this side too.

I reduced the pre-aligned clipping level a litte bit for a much better clearance and closely the same effectivity, and I put the BFO pot to one end to get the basses too. This don't touches the heights, so the sound gets very clear and agressive (good for DX).

For testing I reduced the output on SSB to 300 mW on my Yaesu FT-817 so that another HAM could hear me with only the electret capsule nearly above the noisefloor. He heard me, but poor audio cause of the non-existing S-value close to the noisefloor. Then I put the RF speech processor on and he heard me with radio 4-5 and no problems. Maybe I had a little higher S-value, but his Icom IC-706 didn't react on this. So we only had the hearing difference. And believe him, this was a great difference !!

I'm really satisfied with his additional equipment.

73 from Germany.
Jochen (DG2IAQ)


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05-01-2002 add a comment
FT-817 paddle modification, very useful for CW ops.
Author: Dick AF8X -

I have two excellent pieces of equipment, the Yaesu FT 817 and the Palm Mini-Paddle, which I have combined into an integral unit. The Mini-Paddle comes with an optional magnetic base, however, there is no where on the FT 817 where it can be placed and be in a comfortable operating position, so using this paddle meant attaching it to some kind of base and operating on the desk top in the conventional manner.

The FT 817 has the option of keying the built-in keyer with the mic up and down buttons, enabled in menu # 36. I took advantage of this feature and modified my Mini- Paddle by installing an RJ 45 plug in the base and added an offset tongue to engage the strap bracket on the rig.
The paddle may still be retracted into the housing just as it was intended. To attach the paddle you first engage the tongue into the slot of the strap bracket, and then swing the assembly inward to insert the plug until the locking click is heard. This secures the paddle in an ideal operating position. The paddle can be left attached unless the microphone is needed for phone operation, then a thin piece of whatever is handy, can be inserted between the rig and paddle to release the locking clip on the RJ 45 plug. The paddle may then be removed in the reverse order of attachment.

I have found that having the rig and paddle configured this way is preferable especially when operating portable.




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08-01-2002 add a comment
Yaesu FT-817 CW Filter Installation
Author: Dave Fifield, AD6A -

By Dave Fifield, AD6A

Original 1/19/01

Updated 4/18/01

I received my long awaited YF-122C 455KHz Collins Mechanical CW filter today. It was a snap to install, but there are a couple of things to look out for. Here's the photos and story. Click on any of the photos to see the full size version.

  1. Removing the top cover is simple - first take off the shoulder strap brackets (4 screws) and then remove the 5 screws in the top cover and it pops right off - don't undo the two screws nearest the speaker grille, those hold the speaker in place on the underside of the top cover. Be sure not to damage the speaker wires or connector. The wire from the speaker is pretty short but there's just enough room to get to the connector to undo it if you tilt the top cover up at the rear.

  2. The filter goes in the space at the front of the board.

  3. Here's the filter correctly oriented ready to be put in. Note that the 3 pin connector is on the LHS and the 4 pin connector on the RHS. The filter is installed writing side up as shown.

  4. Here's the filter after installation. It should look like this.

  5. You can go ahead and put the top panel and shoulder strap brackets back on and turn the rig back on. Press the "F" key and hold it for half a second to take you into menu mode. Turn the SEL dial until you get to menu #38. It should say "OP FILTER" and "OFF" just above that. Rotate the main tuning dial until you see "CW" (not "OFF" or "SSB"). Important note - as you go through the "SSB" choice, you will notice that the rig switches to the newly installed CW filter - DON'T PANIC, all is okay. This threw me for a while until I understood what was going on. Make sure that menu #38 is set to "CW" (ignore what the receiver actually does!) and then press the "F" key for half a second again to exit menu mode.

  6. You're almost done. You will probably panic at this time (as I did!) because as you switch through the modes from USB/LSB/CW/CWR etc., the rig seems to be stuck in SSB filter mode. There's one more thing you have to do to get the CW filter working. Check out page 14 of your FT-817 Operating Manual - number 7 at the bottom right of the page you will see the "C-Key" setting for "NAR". You have to set this in order for the receiver to switch to the narrow CW filter when you switch the rig to CW or CWR modes. To do this, first put the rig into CW or CWR mode then tap the "F" key once quickly. The FUNC Keys menu items for the A/B/C pushbuttons should appear. Rotate the SEL control until you see "IPO ATT NAR" over the A/B/C buttons. Then press the "C' pushbutton once to set the filter to Narrow. A small right-pointing arrow should appear and the rig should switch to the CW filter - you should hear a marked difference in the receiver noise "tone".

  7. That's it. You can swap between the SSB and CW filters anytime by revisiting the FUNC Key menu and toggling the NAR function.

How does the filter sound?

I did some preliminary tests with my HP8642B signal generator - the receiver is very sensitive indeed. The CW filter is an ABSOLUTE JOY to has a superb frequency response - very very sharp skirts - great stopband. WOW!!!! I'm blown away by it....I'll have some real measurements to back up my first impressions for y'all sometime soon. It's late, so I tried it on the bottom end of 40m - sounds REAL NICE!!

Folks, if you are going to do CW seriously with the FT-817, you will simply HAVE to get the YF-122C filter option. It's a must have IMO.

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08-01-2002 add a comment
Other Observations/Comments on the FT-817 BY AD6A
Author: Dave Fifield, AD6A -

While I had the top off, I thought I may as well disrobe the rig completely and see what make her tick. Here are some photos of the underneath and front panel etc. The first picture shows the NICAD pack in place.

Notice that there's a small amount of space that could be used for mods or add-ons (hmmm, what else does this rig need though?). Here's a blow up of the mod space.

I went searching for other mod space - there's some between the front panel assembly and the diecast chassis...

...and some more between the CW filter and the chassis in the top compartment:

Here's the PA/Filter board (sorry about the focus). Real small PA (bottom of photo). Very neat.

I also took the front panel off for a look - it simply clips onto the chassis over four little "pips" next to the screws that hold the front edges of the top and bottom panels in place. If you take it apart please be VERY careful not to damage the front panel connector ribbon or connectors - they look fairly delicate!

Lastly, you may notice something a bit odd about the speaker mounting. If you look carefully, you will see that there are several grille holes that the speaker doesn't actually cover. The general concensus is that this improves the audio quality of the RX. A quick test I did to move it shows that it DOES sound better mounted like this.

72, Dave Fifield, AD6A

Email me if you have comments or questions

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Date: 18-03-2002 User comment From: Sylvain F1UJT
Subject: Complete coverage all mode ?

Hi !

All specimen i tryed aren't all mode on all frequencies. I'm interested in receiving 68-88MHz band in narrow FM instead of wide FM. Ideal would be to choose any mode on anyfrequency.



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02-02-2002 add a comment
FT-817 RX-LED disconnect
Author: AA1QG -

By removing a resistor on the back of the front panel you can save approx. 12-15 mA on receive. On long backpacking expeditions this may result in significant power savings.

Disassemble the tranceiver, remove the front panel whilst taking care to carefully disconnect the cable between the front panel and the body of the radio.

Remove the rubber band on the VFO knob, and remove this knob as well as the locker underneath.

Then remove the sel knob by pulling it off. Subsequently remove the screw holding the front panel print and carefully pull out the print card.

The LED is located on the front of the print card, above the hole for the VFO knob. It looks like a small plastic rectangle with 4 connections. You will find two resistors just to the left of the LED.

Remove the resistor which is closest to the VFO hole; not the resistor closest to the top edge.

Carefully reassemble the front panel whilst making sure that all the rubber knobs are in place.

When you power up the radio no green light should be on on receive, whilst the red TX lights up on tx as before.


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01-04-2002 add a comment
FT-817 TX frequency / Region setting
Author: -

These pictures describe the region settings given by the various internal jumper positions in this radio's front panel.

For example, this makes it possible to expand the Tx coverage of a European FT817 so it will work if travelling to the USA but to retain the correct Euro repeater shifts. It should also take away some of the mystery regarding these link settings. Precise information is given of the frequency coverage on each band after modification.

This is untested by me so far. Modify at your own risk. Transmit on designated amateur frequencies only. The warranty may be invalidated by these changes.
Click to download a PDF file.
Thanks to Claus (OZ1ASV) for re-typing the datasheet.
Click to enlarge the pic.
This is the original document.

Date: 21-05-2002 User comment From: ta1cgc
Subject: this config not working

I make any config but not work.... rx is ok! tx not ok. why..... help me please my radio is japan made...


Date: 12-06-2002 User comment From: Lexa, OK1DST
Subject: Japanese version mods

Hi friend,
sorry to say that but as I have information another firmware applied in Japanese version so the only solution is to replace processor itself (as this part of SW is wired inside processor).
Lexa, OK1DST


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16-05-2002 add a comment
Et enkelt front løft til FT-817
Author: LA9MGA -

Av LA9MGA, Helge Karlsen.
Bilder, LA2PIA, Petter Sørensen.

FT-817 er ikke enkel å betjene når den ligger på et bord. Det er umulig å få fingeren under for å dreie på vfo knappen. Etter å ha sett på publiserte artikler hvordan de har prøvd å løse dette problemet, bl.a AR 2, 2002, valgte jeg selv å prøve å finne på noe enklere. Kravet mitt var at den ikke skulle bygge ut noe når den ikke var i bruk, og skulle være på apparatet hele tiden jeg ønsket det.

Jeg valgte å benytte meg av festet for skulder reima. For det første var det jo der allerede, og for det andre befinner det seg nært fronten. Etter å ha undersøkt i garasjen etter noe hensiktsmessig "skrot", fant jeg noen plastdeler som ofte blir til overs når du monterer nytt vinduspusserblad på bilen. Disse ble tilpasset målene på figur. Tykkelsen på plastdelen er ikke oppgitt på fig., men den skal være 2.90 mm. Du kan jo selv måle avstanden mellom skulderreim festet og huset. Plastdelen bør gi litt friksjon mellom hus og skulder reim feste slik at den ikke glir ned av seg selv når den er helt oppe og ikke i bruk. Trekk fra tykkelsen for en evt. beskyttelses tape.
Videre fant jeg en plastpropp som holder det hele på plass. Hullet på 4.20 mm må selvfølgelig tilpasses denne plastproppen og bredden på sporet til reima som jeg har målt til 4,8mm..
Plastproppen gjør at jeg enkelt kan ta bort løftanordningen når jeg vil benytte skulder reima.

Løfteanordningen skyves helt opp i sporet til reima når den ikke er i bruk, og den er dermed nesten helt skjult. Hvis du benytter målene på tegningen, vil dette gi et løft i front som gir en distanse på ca. 2 cm under vfo knapp. Jeg har videre brukt en tape under skulderreim festet (mot huset) for å ikke få mekanisk slitasje og oppskraping av lakk når du beveger løfteanordningen opp/ned. Smurte og på et flytende friksjons stoff på den delen av løfteanordningen som hviler på bordplaten. Plastdelen monteres først under skulder reim festet. Deretter trykker du plastproppen på plass fra yttersiden slik at den går igjennom hullet, men stopper på skulder reim festet. Når du skal bruke festet, drar du plastproppen helt ned til den stopper. Plastdelen vil da følge med. Deretter bøyer du plastdelen forover til den stopper (ca. 25 grader forover), og plasserer riggen på underlaget. Den vil nå stå av seg selv i denne posisjonen. Se ellers figur og bilder. Det er meget enkelt å lage denne anordningen, og du vil fort sette pris på den når du bruker Ft-817 på et bord. Du må selvfølgelig lage en løfteanordning til hver side.

En annen svakhet med den mekaniske konstruksjonen av FT-817 er at anordningene til batteridekslet på undersiden stikker så langt ut at den skraper opp det du plasserer den på. Jeg valgte å benytte meg av 4 runde, småe (ca. 8 mm i diameter og ca. 2.2 mm høye) og gjennomsiktige "gummiføtter" med dobbelsidig tape i hvert hjørne av apparatet. Disse gir også god friksjon så apparatet ikke glir så lett på bordet og passer meget bra tilsammen med overnevnte løfteanordning.

Front løftet i bruk.

Når du drar plastproppen opp, er det meste gjemt bort.

Dette er plastdelene


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08-06-2002 add a comment
FT-817 Mod. 2 Collins Filter (CW AND SSB)
Author: Lutz, W4/DH7LK -

Risk: You will loose the warranty.
Fun: You will have a fantastic rig with a 2.4 Khz Collinsfilter in SSB transmit and receive path and a 500Hz CW filter in the Narrow position for CW and DIG (Pactor, PSK31 etc.

The FT-817 comes with only one slot for additional filters but there is sufficient space to mount both SSB and CW if you remove the PCBs of the filters and wire them directly to the MAIN UNIT.

For the details see the Operation Manual on page 74.

The original filter CF4 will be removed and replace by the YF-122S SSB filter. The YF-122C CW filter will be directly wired to the mounting pins og the optional filter socket.

There is no need to work on SMD components, but you should be very familiar with the tiny circiuts and have the right equipment, if not ask a expirienced OM to help you.


  1. See page 74 of the Operating Manual and follow steps 1 and 2.

  2. Remove the PCB MAIN UNIT, watch on the battery conector and the 3 pin connector in the middle of the board. Remeber or mark the position of the 2 coax-connectors.

  3. Desolder and remove the original ceramic SSB filter, see picture

  4. Desolder and remove the filters from there original PCBs

  5. Connect the SSB Filter with 3 short wires instead of the ceramic filter, see picture

  6. Connect the CW filter with 3 short wires to the pins of the optional filter connector, see picture

  7. Fix the filters in there position with a small ammount of glue

  8. Reassemble the Main Unit, look carefully to the battery connector and the 3 pin connection in the center of the board

  9. Follw the steps 4 to 7 on page 74 of the Operating Manual

...and enjoy the clear signals from the Collins filters.

Vy 73 de Lutz, W4/DH7LK


Original SSB Ceramic Filter removed:
Original SSB Ceramic Filter removed

Position of SSB filter:
Position of SSB filter

SSB filter wired:
SSB filter wired

CW filter wired:
CW filter wired


Date: 10-07-2002 User comment From: Marc PA9MG
Subject: r network?

How about the original R network? On the original Yaesu cw filter is an R network of 2 x 180 ohm serial R's in the output with in the middle a 5k6 R to ground. No C's on the Yaesu option board. (YF-122 C)

Date: 08-03-2003 User comment From: KA7QOR
Subject: Filter PCBs

Great mod idea! I also noticed that there is a resistor network on the pcbs of the filters I purchased. I checked to see if there was enough space to mount the filters as pictured in this mod while leaving them on their pcbs, and I found enough room in my 817. But I did snip a corner from one pcb to make room where it touched the internal speaker. First I removed the pin connecters from the filter pcbs. Everything else is the same as the original mod. I bought my 817 in Guangzhou China in Dec 2002. The mod works great for me!


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31-08-2002 add a comment
FT-817 10 Watts output

There are suggestions to set the FT817 to get the maximum possible output of 15 Watts from an FT817, but I consider this similar to believing in Santa Claus – do you really believe that Yaesu would overdesign the Filters, Relays and Power feeds to cope with THREE times as much power as they advertise the unit for ?

The 15 watt mod also totally disables the DC current limiting. Expect to see charred coils, DC filters and PC board next time you look inside your rig – a fan on the heatsink won’t stop this. For a rig that has no over-temperature indication or protection of any sort, tripling the power level is designing for disaster.

This procedure here will increase power to 10 watts on HF bands only, but ensures that the DC Over-current protection will reduce power into abnormal loads that the SWR detector cannot detect. SWR bridges are a only a compromise at detecting reflected power – that’s why Yaesu went to the effort of building in DC Over-current protection as well as high-SWR protection.

Here is the recommended procedure, you will need a Dummy Load and a Wattmeter or RF Voltmeter. Make a note of your original calibration settings so you can go back to the standard setting later – the easiest way to do this is to use FT817 Commander freeware. It is also easy to accidentally change a value by bumping the Dial knob, and you need to be able to get back to the original setting.

If you have a Key connected, set the VFO to CW on 1.8, 7 and 21 MHz bands – if you don’t have a Key, then set them to PKT and you will be able to get full carrier using Mic PTT but with no modulation going out.

Turn the radio off. Press and hold the three A, B, C buttons and press the PWR button. To change to a different Menu item turn the small SEL knob. To change the value of the item, turn the large Dial knob. Be careful not to bump the Dial knob so you don’t accidentally change settings..

  1. Increase HF1-IC to 150.

  2. Increase HF1-HI for an output of 14 watts - you will need at least 12 volts input.

  3. Decrease HF1-IC until you get 12 watts output

  4. Now set HF1-HI for 10 watts output.

  5. Repeat for HF2 and HF3

You could also change HF1-L3 to 5 watts to save battery drain when 10 watts isn’t needed.

If you are using an RF Voltmeter the readings are 0.5W=5v 1W=7v 2.5W=11v 5W=16v 10W=22v 12W=24v 14=26v.

To avoid de-calibrating the Voltmeter, set your supply to 13.8 volts – otherwise if you just flick over the DC volts position (Item 17 - VCC) you will recalibrate it.

To save these changed settings, hold the F button for two seconds when finished.

Date: 12-09-2002 User comment From: Nuno
Subject: Author

Why does this mod isn't signed? Does he have the experties? Hummm...

Date: 16-10-2002 User comment From: vr2xmc
Subject: blown finals and 10 W modification

Hi OM,

This topic is very hot in the world wide FT817 discussion groups.

I think we have to strike the balance of getting 10 watt output and risk of blown finals. Increasing the output power is definitely not an original design parameter. Otherwise, Yaesu should promote the rig as 10 watt output and sell for higher price.

Based on this rationale, I keep the variations to the orignial values in the hidden menu #18-53 as few as possible. My rig is the Lot 58 production and my observations are:

1.The gain of the finals at VHF and UHF regions is well less than that in HF region so that there is not much room for increased output. For example, the difference between 7 watt output and the original 5 watt is merely 1.46 dB. Therefore, why border to make any variations to the original values.

2.For HF and 50Mhz, an increased output to around 10 watt can be obtained by simply only changed the values at #24,28,32 and #36 i.e. HF1-HI, HF2-HI, HF3-HI and 50M-HI. Therefore, the changes to the original design parameter are kept to minimal. In other words, there is no change in values for the parameters such as overcurrent protection and TX gain. Although in some bands, you may only get an output of 8-9 watt, the on-air difference is minimal.

3.Once you make the modifications, I would strongly suggest you strictly limit your operation to light duty cycle mode such as SSB when running 10 watt.

4.The theoretical absolute maximum power the pair of finals is 8 watt x 2. Therefore, you should not aim at running the rig at 15 watt !!!!

The above is my own observation to my rig. Please don't hold me liable for any damage to your rigs. Good luck!


Johnny Siu VR2XMC

Date: 07-03-2003 User comment From: lz2ssb
Subject: 10w!

the modifications work very well.THANK YOU!

Date: 08-04-2003 User comment From: anonymous
Subject: FT-817 10watt radio??


I don't know whether anyone else agree's with me, but WHY increase the FT817 to 10w?

If Yaesu / Vertex Standard intended to make the FT-817 a 10watt rig, then they would of. Why risk blowing the finals and then pay out lots of cash to get it fixed.

My Motto is, if it's working... DON'T MESS WITH IT!


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06-10-2002 add a comment
Yaesu FT-817 CAT interface
Author: Edwin - PE1PWF -

Dit interface is bedoeld om een Yaesu FT-817 te besturen via de PC. Het kan worden gebruikt om modes, frequenties of geheugenkanalen aan te passen met verschillende programma's zoals: MixW, RATS FT-817, TRX Manager, FT-basic enz.
Yeasu verkoopt volgens mij een dergelijke kabel onder de naam CT-62, maar die heb ik zelf nog niet gezien.
Het IC, de MAX232 is veelgebruikt om RS232 signalen om te zetten naar TTL, maar omdat niet iedereen hem kent heb ik er onderstaand schema bij gemaakt. Let op, ik heb het zelf gebouwd, en het werkt goed, maar als je zelf gaat knutselen is het natuurlijk voor eigen risico.
Oh ja, let wel op dat je de juiste "CAT rate" insteld, anders kan de set verkeerde dingen gaan doen, zoals zenden op de verkeerde band of zo.
Uitschakelen gaat dan slecht, helemaal als ook de accu er nog in zit!



Opmerkingen bij rev.2

Het heeft even geduurd maar hier is dan eindelijk ook een lay-out bij de interface. Voor deze lay-out heb ik de 2 andere poorten van de MAX232 gebruikt, dus dit schema ziet er iets anders uit als de vorige.
Ik had zelf het geheel al eens op de swhh methode in een 9-pins sub-d connector gemonteerd, maar binnenkort hoop ik hier ook een SMD lay-out te kunnen plaatsen die geschikt is om in een 9pins connector te monteren.
De lay-out voor de interface is een BMP bestand, helaas gaat printen dan wat onhandig, maar met bijvoorbeeld Irfanview kun je het afdrukformaat mooi verschalen. Ik gebruik versie 3.17 en als ik het plaatje afdruk op 1.05x dan is het formaat precies goed. (ik zal proberen dit binnenkort in een PDF bestand te zetten of zoiets).
De maten van de print zijn 69 x 42,5mm, de steek van alle condensatoren is 5mm. Irfanview kunt u vinden op of bijvoorbeeld via TUCOWS .



Notes with revision 2

It took a while, but here is the layout for the interface. I made a modification to the "original" circuit because the second set of ports in the MAX232 are better for making a nice PCB.
I hope I can present a second PCB within a few weeks that can fit in a 9 pin sub-d connector, unfortunately this means soldering some SMD.
Unfortunately I had to use a bitmap-file for the layout, you have to scale this to a PCB size of 69/42.5 mm.
I use IrfanView (version 3.17) for printing my PCB-layout scaled x 1.05 gives me the correct size. (I will try to use PDF file later, or some other format)

You should be able to find IrfanView on Homepage IrfanView.

73, Edwin / PE1PWF


Click here to get the BMP file of the PCB 13 Kb.

For an exact print of the PCB you should use this PDF file of the PCB.

Software for using the CAT interface can you find on this links:

Direct download the FT-817 Commander (HB9DRV).

This article can also be found at


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12-10-2002 add a comment
Yaesu FT-817 Mod/Fix
Author: Tom

I am posting the following as a service to all 817 owners. Even if you do not experience these 70cm transmit problems, I would not be surprised to find out that this fix also improves receive by making the radio quite a bit more quiet---here is my story

Recently I found that my 817 occasionally did not put out any power on 440 transmit when using a duck on the front BNC.

Further examination showed that when set to low power and the antenna was flexed just so the power meter would peak but actual output power dissappeared.

Some experimentation showed that grounding the big covered can on the main board solved the problem. A bit more investigating showed the bottom of the main board is not well grounded.

A little search work produced the official Yaesu fix document (the actual document used at Yaesu) along with part numnbers needed to implement the fix (avaliable from Yaesu, or you can send the rig to them and wait for them to repair it). Yaesu will fix the rig for free if it is under warantee. If not you will have to order the fix part (the part# is in the attached tiff file), dont worry it only costs .22 USD (22 US cents).

This is not a lot specific problem (according to Yaesu), and rigs as recent as a year 2001 lot 44 rig has the problem (A rig produced around the end of 2001).


The official Yaesu fix is under the filename, 817ground.tif.

73 and good luck!

Date: 14-10-2002 User comment From: Orla Saabye OZ1KRI
Subject: Larger picture ?

Is it possible for you to send me an larger picture, the picture in your article here is of no value for me as i am not able to read it, using 1024 * 768.

Thats all.

VY 73 De Orla Saabye

Date: 16-10-2002 User comment From: anonymous
Subject: 817ground image


Saw your posting on

A full size tif image of the 817 fix can be found in the files section of the
yahoo group for the 817:

Its not a perfect image but it is as good as possible.

You may have to join the group to get in. It is free and a good
resource for 817 owners.

73 and good luck

Date: 16-10-2002 User comment From: anonymous
Subject: same pic

Actually a closer look and it seems like the tif file is the same full sized version in both locations. Unfortunately this is as good as it gets.

Date: 23-10-2002 User comment From: DH5ST
Subject: 70cm Problem


I have a similar Problem:
Output disapears and PwrMeter shows more then maximum regardless
of the Output power set.

But the Problem appears only if the external Voltage is greater than 12 V. If it is less than 11,8 V 70cm is working UFB.

Is the Fix mentioned above also applying ?



Date: 27-10-2002 User comment From: Gene Brewer KI6LO
Subject: Leaf Spring Installation

I saw the write up for the grounding spring. Checked my FT817 (Serial No. 1K440097 purchased AES Las Vegas, NV July 2002) and it is already installed from factory. Not sure when Yaesu started installing the fix. Thanks Gene KI6LO

Date: 05-11-2002 User comment From: anonymous
Subject: a twist on the mod

After checking to see if I had the mod inplace I did, but I still had the same tx problems.

I tried soldering a leaf spring I ordered to the top of the large metal can on the top board in an effort to ground the can to the rig's case.

Problem solved.

73 and good luck


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04-01-2003 add a comment
KA7OEI FT-817 page

The Yaesu FT-817 is an extremely portable HF through UHF all-mode transceiver, capable of operation on all amateur bands from 160 meters through 70 cm (excluding, unfortunately, 222 MHz.) It is also considered to be a QRP transceiver - being capable of only 5 watts output maximum. In addition to transceive operation on these amateur bands, it also is a capable general-coverage receiver providing continuous coverage on all modes from 100 KHz through 56 MHz, 108 through 154 MHz, and 420 through 470 MHz. It also provides "Wide FM" receive coverage from 76 through 108 MHz.

This link is divided into several several sections to make digesting the material more manageable:


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06-04-2003 add a comment
Improvement of stock mic for FT-817
Author: Jochen Heilemann, DG2IAQ -

If you open the original microphone you can see two parts near the tone switch;..a resistor of 680 Ohms and a electrolyt capacitor of 0,33µF.

You get a higher audio level by removing the 680 Ohms resistor cause this is ALWAYS paralleled to the dynamic mic capsule, regardless of the position of the tone switch. On the other hand without the resistor you have to change the capacitor too to get a equal tone switch effect.


So on mine I removed the resistor and replaced the 0,33µF electrolyt with a normal keramic capacitor of 22nF (0,022µF). For my opinion all values between 22nF (0,022µF) and 100nF (0,1µF) would be ok.

Now you can notice a greater possible distance to the mic without the strong break in of the audio level. So this means the speaking distance to the stock mic can vary more without loosing too much audio level.

Best regards from Germany.

Jochen Heilemann, DG2IAQ


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09-04-2003 add a comment
FT-817 FM mod improvement (more basses)
Author: Jochen Heilemann (DG2IAQ) -

First I was satisfied with my Yaesu FT-817 (s/n 2J56..) with its original dynamic microphone. The sound was very good for a non-high-fidelity dynamic capsule. But as I decided to build in the DF4ZS rf speech processor into the stock microphone I wanted to be able to use the FT-817 on FM too. A rf speech processor isn't designed for that, so now I use the backward switch to switch between the electret capsule (output via a 4.7mF tantal) or the whole rf speech processor.
The tone switch capacitor of 0.33mF was removed, but the 680 ohms resistor was put in place. If you remove the 680 ohms resistor too you would overdrive the FT-817 mic amp input and distortion would result.

But with the lonely electret capsule I noticed a shrill, bright FM modulation with really no basses in the sound characteristic !! The modulation sound characteristic of course was real good with the dynamic microphone, but with a even better electret capsule FM isn't really usable. So what happens ?

I have the MH-36 DTMF microphone on my FT-90 and people who use this mic on the FT-817 should expire the same shrill sound in my opinion too, cause there are nearly the same few external components in the mic line like on my modificated stock microphone. No problem on SSB (AM I've not tested). So the problem only can be in the FM modulator part of the FT-817.

After looking into the circuit diagram I found the fault very fast. The input capacitor at the beginning of the amp/limiter/lowpass line of the FM modulator has a too low value. It builds up a af highpass with the input impedance of IC Q1096, but I can't say where the lower frequency corner is. But depending on the resulting sound it must be over 600 Hz or more !

So here my mod:

Replace C1380 on the down side of the main unit with 0.033mF (original value is only 0.0047mF !!!)

On mine FT-817 I soldered a 0.022mF SMD capacitor over C1380. So I get a total value of nearly 0.027mF.

Now the sound is absolutely great. I reduced menu #29 (FM mic) from original 50, and 70 with the dynamic capsule, down to only 15 ! But the modulation sounds even better than original, is much louder than original, has basses and heights and is nearly the clipping level on the peaks. A real FM DX modulation.

For sure I even can't use the DF4ZS rd speech processor on FM in addition, that would be too much stuff, hi. But with this mod you don't need it on FM.

Click to zoom.


This mod is only for the real specialists !!! You'll understand that when you see the real tiny size of the C1380 capacitor on the board. Do it on your own risk !

Best regards.

Jochen Heilemann (DG2IAQ)

Date: 17-04-2003 User comment From: Jochen Heilemann (DG2IAQ)
Subject: Mistake, mistake, mistake ! ! !

I'm so sorry, but the number of the capacitor is wrong ! C1380 is not correct, cause this is on the lowpass side and a raising value would produce a dark, hollow sound !

The correct part-no. is capacitor: C1385 (0.0047mF).

But don't worry, the image show the right place of the capacitor the mod works.

I only recognized the fault as I looked into the circuit diagram today. It must be latenight, as I wrote the mods, hi....

73 from
Jochen (DG2IAQ)


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