The TS-940S Mods Reviews

The TS-940S Mods Reviews

From: aridio2@uninet.com.br
Sent: segunda-feira, 13 de setembro de 2004 23:58

Subject: TS-940 - Erros e outras coisas mais

Boa noite.
Caros amigos;

1o- Na construcao desses FETS a dopagem
do canal eh uniforme e por isso tanto
faz dreno ou fonte. PODE INVERTER.
Claro que isso nao exime de culpa o
miseravel do desenhista e do revisor
tecnico da Kenoowd.

Eu mesmo inverti propositadamente
quando li essas informacoes ha 25
anos atras quando estava na engenharia.
Sai invertendo BF245, BF256, MPF102,
MPF112 em circuitos de RF e de audio.
Nao ha diferenca nem de polarizacao
nem de ganho.

2o- Tenho a "satisfacao" de utilizar um TS940,
cedido "gentilmente" por um grande amigo
meu, que esta CHEIO (o radio) de maus contatos.

O dito cujo (radio) estava na minha bancada,
como quase sempre, deitado, quando resolvi
assoprar uma "poeirinha" que estava na PLACA
DE RF. No instante que assoprei a recepcao
despencou!!!!!!

PORQUE? Porque a umidade bateu na placa de
FENOLITE e alterou a polarizacao fornecida
pelo CAG AOS FETS DE ENTRADA.
Com um tubo de esferografica sai soprando
em varias areas pra identificar as mais sensiveis.

Peguei um secador de cabelos e passei
sobre a area e a recepcao voltou ao normal.

ACREDITO (?) que a mudanca de sensibilidade
observada pelo Nelson Ricardo foi provocada
pala DESSOLDAGEM E RESSOLDAGEM dos FETS, que
"teriam" (?) retirado umidade da dita cuja.
Que alias, umidade eh o que nao falta la
pelas terras altas do meu amigo Nelson.

Abraco a todos.
Acredito que em breve estarei de volta
ao ar (com TS940 com FET invertido),
assim que me livrar de umas provas.

From: Fernando Rodrigues [py1fr@aol.com]
Sent: segunda-feira, 13 de setembro de 2004 20:53
To: Eduardo Guisard

Subject: RE: TS-940 - Erros de produção encontrados 25 anos depois www.guisard.com

Prezado Eduardo,

Troquei de posição os um dos Fet´s Q10 na RF Unit e o Q4 na FI Unit, conforme as fotos.
Por incrível que pareça não notei nenhuma diferença.
Para efetuar a comparação antes da troca apliquei um sinal com o gerador de RF em 14 MhZ que indicava S9 no

S-Meter do rádio e fiz o mesmo usando o sinal de calibração do próprio radio.
O mesmo nível foi aplicado após a troca e o sinal era exatamente o mesmo!
Depois fiz a troca do Q4 e não percebi diferença na atuação do AGC. Algumas modificações para melhorar o AGC

estão no site www.mods.dk ou no site da kenwood (service bulletins).

Como reportei antes ainda acho que um pequeno toque no VR2 na RF Unit, causa um tremendo efeito.
Este trimpot costuma apresentar mal contato.
Não sei porque os transistores Q6, 7 e 8 na RF Unit esquentam tanto. Não dá para por o dedo.

No mais vou continuar observando o TS-940S e tentar entender porque trocando de posição os Fet´s não notei diferença.

Grato e até breve,

Fernando Rodrigues
py1fr@aol.com
21-26104097
21-26672950
21-94655974

From: Fernando Rodrigues (py1fr@globo.com)

December 27 2004
Prezado Nelson. Confirmo a melhora na recepção do meu TS-940S após a inversão dos Fet´s.
Eu havia efetuado a inversão sem contudo atentar para um problema de mau funcionamento no trimpot VR2,
que mascarava a melhora na recepção. Tive o cuidado de recolocar os Fet´s no lugar para perceber a melhora
e constatei que em 1,8 Mhz + 6 db´s e em 28 Mhz + 12 db´s. Excelete valeu a dica. Vou aguardar a troca por um
Fet mais moderno. Até breve

From: ModsAndRepairs@eham.net [ModsAndRepairs@eham.net]
Sent: terça-feira, 14 de setembro de 2004 00:52
To: eduardo@guisard.com
Subject: [ModsAndRepairs] RE: TS-940 25 years old production errors

Posted By K1WW

BE CAREFUL.. This may or may not be correct. They may be wired this way for coupling not for RF
amplfication. 17 db of additional gain might not be desirable and create circuit instability or overload.

From: Lau, Zack, W1VT [w1vt@arrl.org]
Sent: terça-feira, 14 de setembro de 2004 09:20
To: Eduardo Guisard
Cc: Schetgen, Bob, KU7G
Subject: [Spam] RE: TS-940 factory Assembly Error

Hi Eduardo,
I am forwarding your message to Bob Schetgen, who edits the Hints and Kinks column.
73--Zack W1VT

From: Schetgen, Bob, KU7G [ku7g@arrl.org]
Sent: quinta-feira, 16 de setembro de 2004 13:19
To: Lau, Zack, W1VT; Eduardo Guisard
Cc: Weinberg, Maty
Subject: [Spam] RE: TS-940 factory Assembly Error

Hi Eduardo,
Zack Lau, W1VT, forwarded your message to me as the Hints and Kinks Editor.
Regretfully, I can’t use your article. I receive far more material than the Hints & Kinks column can possibly
contain, so I must return many excellent hints like yours. Thanks for your offering and please
send along anything else that you think useful for H&K.
73, Bob, KU7G

From: n6ki@juno.com [n6ki@juno.com]
Sent: terça-feira, 14 de setembro de 2004 04:45
To: rio1020485@terra.com.br
Subject: [Spam] Re: [CQ-Contest] TS-940S Production Mistakes

Dear OM,

Can you tell me the first digit of the Serial Number that 'is on teh Bottom cover of the TS-940 you found had this problem.

In my experience with the TS-940 over many years, I have found that
Serial Numbers with first digits of either 5 or 6 had many problems as these were the first two years of production of
the TS-940 ( 1985 and 1986 )

By the time Kenwood had gotten to Serial numbers 7,8,9,0,1,2 ( 1987 - 1992 ) Most of these later radios did not have
many problems.

73, Dennis N6KI
San Diego

From: Ôàëüøóíîâ Â.Ã. [ptoermak@salekhard.ru]
Sent: sexta-feira, 17 de setembro de 2004 02:09
To: eduardo@guisard.com
Subject: TS-940S

Hello Eduardo,
Thanks for Your curious information of errors in TS-940.
I also find thees errors in my TS-940. I did correct them, but have no much difference.
I did no measure this improve with some measurement, only with my ears. Did you measure IMD
level of Your TS-940 before and after correction. It is would be interesting. I gues IMD must be improving now.

Best regards,
Vlad UA9KAA ptoermak@salekhard.ru

From: KCC-Amateur [kcc-amateur@kenwoodusa.com]
Sent: segunda-feira, 20 de setembro de 2004 13:13
To: Eduardo Guisard
Subject: [Spam] RE: Feedback from Kenwood.net

Dear Kenwood Customer:

We have already view your web page. The view on page 90 in the service manual, and in the TS-940S are correct.

Kenwood Japan re-confirmed this last week, due to your correspodance.

If you need further assistance, please e-mail us again.

Sincerely,

Kenwood Amateur Radio Customer Support

From: Frank Strecker [fs0nb.de@gmx.de]
Sent: domingo, 26 de setembro de 2004 15:03
To: eduardo@guisard.com
Subject: [Spam] TS-940S Factory Assembly Mistakes

Hello Nelson Ricardo, PY1NR !

Thank you for your marvelous and ingenious work!

I accomplished their corrections with success at my TRX (TS-940S AT).
After which I had to state that Q4 and Q10 had the wrong position also in my equipment.

They are right completely:

- The RF gain increased and the noise decreased.
- The RF profit is more than 10 dB, 1.5 S-Values.
- The AGC is working now very fine. I had to also again adjust my signal-strength meter.

I thought, an amplifier my friends would have added themselves. HI - Smile!

Please you excuse my bad English.

Greeting from Germany, JO63PN,

73´s Frank

From: Corbeck@awaforums.com [Corbeck@awaforums.com]
Sent: segunda-feira, 27 de setembro de 2004 19:20
To: eduardo@guisard.com
Subject: [Spam] Thank You Re. the 940!

Thanks very much for the article on the 940. I have
one of these and noticed the S-meter always
seemed a little low, but always accepted it.

Now I will have to take a look at it after your
excellent research.

Regards from Colorado!

Mark Stappenbeck, N0PWZ

De: "John Reynolds" John.Reynolds@hsc.utah.edu
Para: eduardo@guisard.com
Cópia:

Data: Mon, 27 Sep 2004 15:46:57 -0600
Assunto: [Spam] TS-940S

Hello,
I want to express my gratitude for taking the time and effort to
inform us 940 users of this valuable information and for doing it
in such a very fine manner !

I love my 940 and will own it until I am SK. I plan to open it up and see if mine is also problematic.

My 940 is of the 900 mil plus serial number. I wonder if they knew
this problem at that late production date. I'll look and see.
I deeply appreciate your efforts and I'll let you know what I find.
73,
John N7QF
Utah

De: "Pe3mco" Pe3mco@pe3mco.net
Para: eduardo@guisard.com
Cópia:
Data: Mon, 27 Sep 2004 19:53:34 +0200
Assunto: TS-940S Mods Questions

Hi There.
Very good info about the TS940S
I will take a look in de radio and will try to fix this error.
But I also have another question.
Do ya know any dealer of part dealer that have a spare pc board. Digital A unit.
I’m looking for one because mine is a bit crapy…
Tnx for the reply .
Marco PE3MCO

From: Frank [fs0nb.de@gmx.de]
To: eduardo@guisard.com
Cc: fs0nb.de@gmx.de
Subject: [Spam] TS-940S Factory Assembly Mistakes
Hello Nelson Ricardo, PY1NR !

Thank you for your marvelous and ingenious work!

I accomplished their corrections with success at my TRX (TS-940S AT).
After which I had to state that Q4 and Q10 had the wrong position also in my equipment.

They are right completely:

- The RF gain increased and the noise decreased.
- The RF profit is more than 10 dB, 1.5 S-Values.
- The AGC is working now very fine. I had to also again adjust my signal-strength meter.

I thought, an amplifier my friends would have added themselves. HI - Smile!

Please you excuse my bad English.

Greeting from Germany, JO63PN,

73´s Frank

From: Jean-Yves Louchin [jlouchin@procie.fr]
To: eduardo@guisard.com
Cc:
Subject: TS-940S Modifs Questions

Bonjour cher Om et je vois que vous connaissez bien cet appareil .
J' en possède un depuis peu de temps et l'OM qui me l' a vendu d' occasion ne m' a pas parlé de différentes
petits problèmes que l' appareil possède.
En parallèle d' un problème évident de CAG et de souffle apparaissant et disparaissant par intermittence
( il s' agit peut-être de l' erreur que vous décrivez) j' ai également un problème du côté des mémoires et de
l' accès direct aux bandes qui ne fonctionnepas toujours, ainsi que le petit afficheur LCD qui me joue des tours !

From: KCC-Amateur [kcc-amateur@kenwoodusa.com]
Sent: segunda-feira, 20 de setembro de 2004 13:13
To: Eduardo Guisard
Subject: [Spam] RE: Feedback from Kenwood.net

Dear Kenwood Customer:

We have already view your web page. The view on page 90 in the service manual, and in the
TS-940S are correct.

Kenwood Japan re-confirmed this last week, due to your correspodance.

If you need further assistance, please e-mail us again.

Sincerely,

Kenwood Amateur Radio Customer Support

From: john reynolds
To: eduardo@guisard.com
Sent: Tuesday, September 21, 2004 7:51 PM
Subject: TS940S

I recently received your info on the incorrectly installed FET's in the TS940S,thank you for this advice.

For some time I have experienced a fault on my TS940S.... When I try to change frequency to 21 Mhz or
higher the display shows only a line of dots "..............." and I cannot receive or transmit.
Then after leaving the set on for say 30 minutes it will come to life again,it's most annoying!

Have you heard of this fault,other owners in the U.K. are also experiencing it..........do you know the cure please.

73 John G3RSD

From: John Reynolds [John.Reynolds@hsc.utah.edu]
Sent: segunda-feira, 27 de setembro de 2004 18:47
To: eduardo@guisard.com
Subject: [Spam] TS-940S

Hello,
I want to express my gratitude for taking the time and effort to inform us 940 users of this valuable
information and for doing it in such a very fine manner ! I love my 940 and will own it until I am SK. I plan to open it up

and see if mine is also problematic. My 940 is of the 900 mil plus serial number.
I wonder if they knew this problem at that late production date. I'll look and see. I deeply appreciate your
efforts and I'll let you know what I find. 73, John N7QF Utah

De: "f6gox" f6gox@free.fr
Para: eduardo@guisard.com
Cópia:
Data: Thu, 30 Sep 2004 16:56:13 +0200
Assunto: TS-940S Modifs Questions

Bonjour ricardo et tout simplement Bravo !!

j'en rigole encore !!

personnellemnt j'ai un FT990 et les modifications del'étage d'entrée que
l'on constate sur les différentes série de fabrication n'ont jamais été
documentées sur le schéma ... ainsi va les essais des ingénieurs ...

encore félicitations et 73 qro

Laurent F6GOX PARIS

De: PlanerGuy@aol.com
Para: eduardo@guisard.com
Cópia:

Data: Mon, 04 Oct 2004 18:06:21 -0400
Assunto: TS-940S Mods Questions

I wanted you to know that I performed the FET reversal, as you explained it, and
I'm much impressed.

The receive came up so much that I'm unsure how to reset the "S" meter. I'm thinking of not resetting it, but running the

Attenuator at -10db. Receive enhancement is actually closer to 15db on my rig, but that's a good compromise.

Also of course, my noise compared to signal has also improved. When I want the stronger receive
I can just remove the attenuation.

Thanks for sharing your findings with your fellow Hams and TS-940 owners.
Please keep us posted on any improved fets we might use to replace the
2SK125'S, should you find them. That might make the 940 one of the Great
receivers!

Thank you again, Sir.

Kevin Mccracken - KC8GIA

De: "N4CH" N4ch@aol.com
Para: eduardo@guisard.com
Cópia: N4ch@aol.com
Data: Thu, 07 Oct 2004 14:38:04 +0200
Assunto: [Spam] TS-940S Factory Assembly Mistakes

Hello OM Nelson,
I recently purchased a used TS-940S at a hamfest (it was in excellent shape, I was lucky), but it came with no CW filters,

so I ordered some from INRAD to install. Just before I opened the radio to install the filters, I checked the MODS.DK

website to find out how to modify the radio for general-coverage TX (I want to use it on 60 meters). I saw your excellent

write-up on the 2 corrections you made to your radio.

My TS-940S (serial number 7070266) had both FETs installed wrong, so I decided to do the changes.
Although the improvement was not quite as big as yours, I did see some improvement.
I used a good signal generator to verify the results.

I calibrated the test setup before I started, and made the two changes one at a time.
Reversing the leads on Q10 produced a 2.5 to 3.0 dB improvement, and then rotating Q4 added another 1.0 to 1.5 dB.

Total net improvement was 4.0 dB or so. I do not have any new FETs (they are getting hard to find), but perhaps this would

have made further improvement.

Anyway, I thought you would be interested in my results, in case you are collecting data.
TNX and VY 73,
Herman, N4CH

From: ANTONIO CARLOS COLNAGHI [accolnaghi@ig.com.br]
Sent: sexta-feira, 8 de outubro de 2004 21:48
To: rio1020485@terra.com.br
Subject: Fw: Divulgação Erros de Fábrica no Transceptor TS-94 0S

Boa noite Eduardo.
Para publicarmos uma notícia dessa, temos que ter no mínimo uma autorização da Kenwood.
Caso a consiga, retorne que publicaremos.

73s de Antonio Carlos Colnaghi - PY2ADZ
Mantenedor do site da LABRE-SP, hoje com 400.000 visitas às 19:09 hs

From: Joel Rodriguez [n6toc@netzero.com]
Sent: segunda-feira, 11 de outubro de 2004 01:04
To: eduardo@guisard.com
Subject: TS-940S Mods Questions

Ricardo,
Congratulations on your find,who will imagine this to be discover after so many years. I'm a Kenwood TS-940s owner

for so many years and now that I see your discovery
I have more faith on the 940. I will test mine and look for the described errors and hope to find the same so the

performance of my 940 will improve.

Congrats again and thank you for such important discovery.
73's de Joel / N6TOC

From: randy mitchell [cowboy55@nycap.rr.com]
Sent: quinta-feira, 14 de outubro de 2004 23:57
To: eduardo@guisard.com
Cc: cowboy55@nycap.rr.com
Subject: [Spam] TS-940S Factory Assembly Mistakes

hello . i have a kenwood nice ts 940 i like for you to fix this mistake and the am swing back??
on 5 watts or 60 watts some one said to me it is
the alc i dont know ? can you help me can i call you . and i can send radio to to fix .
Please get back to me thank you randy

De: "Carl Motsinger" cmotsinger@letterlogic.com
Para: py1br@guisard.com
Cópia:
Data: Mon, 18 Oct 2004 06:19:23 -0500
Assunto: [Spam] TS-940S Mods Questions

HI

I did the first mod - RF board and it
did indeed improve the sensitivity. Not
a lot but there was an improvement.

I will attempt the other IF mod the next
time I have to get inside the radio
for a repair or mod.

Carl N9EFJ

From: chris [christspi@hotmail.com]
Sent: domingo, 31 de outubro de 2004 14:48
To: eduardo@guisard.com
Subject: TS-940S Modifs Questions

Bonjour, je me permet de vous écrire car mon ts 940s est tombé en pane..... C'est fort dommage!!!!
En effet, je met le poste en fonction, ce dernier 5 seconde après, coupure total.
Comme si l'alimentation avait lâché....
Je vois que vous connaissez très bien ce poste.
Alors je me demande si s'est pas une pane répétive que j'ai là.
Et me permet de vous demander si vous n'avez pas une petite idée sur la question. je pense que s'est l'alim, mais pas sur.
Par ailleurs, j'ai lu votre article avec intérêt. D'ailleurs, mon poste à la platine un peu noircie à cette endroit ou le

composant est à l'envers.... D'autre part, je vais regarder à Genève si je trouve
les composant manquant mentionné dans votre article. je vous remercie par avance de votre réponse....
Christian Spalvieri Genève

From: chris [christspi@hotmail.com]
Sent: quarta-feira, 3 de novembro de 2004 20:52
To: eduardo@guisard.com
Subject: Re: TS-940S Modifs Questions

Bonjour Eduardo, j'ai contrôlé la sortie alim. Il y a deux fois 30v.... Sortie pont de diodes 42v sur x43 1500 je n'ai pas de tension?

J'ai changé les deux transistors de l'alim, j'ai aussi changé le pont de diodes je n'avais
pas de s15 vb. Alors j'ai mis un pont kbpc 3510..... Je ne vois ce que peut être le problème.
Est ce que les condensateurs peuvent être en cause? Dans tout les cas je vous remercie de votre réponse....
Mais je crois bien que c'est cuit pour mon poste, c'est un poste que j'aimais bcp. Malheureusement le prix d'une réparation

chez un agent kenwood ne vaut pas la peine....
Eduardo passes une bonne journée merci encore à vous Chris

From: RalphWanadoo [louail.georges@wanadoo.fr]
Sent: sábado, 6 de novembro de 2004 20:27
To: py1br@guisard.com
Subject: [Spam] TS-940S Modifs Questions

Bonsoir,
Et bravo ! je suis stupéfaits ; j’ai un 940S je ne m’en suis jamais rendu compte, je vais vérifier.
73 super Qro de F5OEE

From: Robert W Sitterley [k7pof@juno.com]
Sent: domingo, 7 de novembro de 2004 23:47
To: py1br@guisard.com
Subject: [Spam] TS-940 S Mods Questions

Nelson:
Thanks for the fine article on the two backwards FET's in the TS-940.

Below is a link to possible replacements there are also link to data pages on the same page.

http://www.mouser.com/index.cfm?&handler=data.listcategory&D=*2SK125*&ter
ms=2SK125&Ntt=*2SK125*&Dk=1&Ns=MfgrPartNumber%7c%7cSField&N=0&crc=true

73 Bob K7POF

From: Thomas Sukamto [yc3bdj@telkom.net]
Sent: terça-feira, 9 de novembro de 2004 23:07
To: 'Eduardo Guisard'
Subject: [Spam] RE: TS-940
Thanks for your Email,
In my Email to PY1NR I’m just saying thank you to you regarding a mistake by kenwood in TS 940.
What you found in TS 940 is really fantastic. I have reported also what you did to kenwood corp.
I will forwarded my email to you .
Thank you
de YC3BDJ

From: KCC-Amateur [kcc-amateur@kenwoodusa.com]
Sent: Monday, November 08, 2004 11:38 PM
To: yc3bdj@telkom.net
Subject: RE: E-mail reference #M329802

Dear Kenwood Customer:

There is presently information out on the web indicating that components in the TS-940S are in the wrong location.
That is INCORRECT, the location and position of Q10 in the TS-940S service manual PC Board Views on page 90,
and in the TS-940S itself are correct. Kenwood Japan re-confirmed this 09/19/2004.

If you need further assistance, please e-mail us again.

Sincerely,

Kenwood Amateur Radio Customer Support
Audio Products

Name : Thomas Sukamto
Email Address : yc3bdj@telkom.net
Country : USA
Subject : Comment
message : I found the informations form this site
http://www.guisard.com/Index_TS940_english.htm with subject :TS-940S Factory Assembly Mistakes.

Please your comment.
Thank you.

From: Thomas Sukamto [yc3bdj@telkom.net]
Sent: terça-feira, 9 de novembro de 2004 23:09
To: rio1020485@terra.com.br
Subject: FW: FW: E-mail reference #M329802 - TS940S weakness

This is comments from my college in W land to Kenwood corp.

From: AB 2 QV [ab2qv@hotmail.com]
Sent: Tuesday, November 09, 2004 11:33 AM
To: kcc-amateur@kenwoodusa.com
Cc: yc3bdj@telkom.net; nraicher@yahoo.com.br; ab2qv@yahoo.com
Subject: RE: FW: E-mail reference #M329802 - TS940S weakness

This is my response. The original position of Q10 and Q4 were correct based on the original diagram stated on both the

instruction manual and the service manual. But it results lower dB and weaker Rx compared to when the transistors are

installed 180" or being reversed. Mr. Ricardo, PY1NR, from Brazil <nraicher@yahoo.com.br>, who originally found the

mistake and corrected it. Since then there are many TS940S and TS940SAT owners do the same he did. Please check his

website at http://www.guisard.com/Index_TS940_english.htm and give him feedback. Before that, please try yourself to reverse the position of the transistors. Please measure the S meter before and after reinstallation. Turn on the rig and do Rx. See the difference. Then give us feed back. Thank you.

Your loyal customer or Kenwood rig owner,
Wyn, AB2QV.
ab2qv@yahoo.com

From: de.marinis [de.marinis@globo.com]
Sent: quarta-feira, 10 de novembro de 2004 10:30
To: py1br@guisard.com
Subject: Dúvidas TS940S

Caro Nelson
Muito obrigado pela descoberta deste dois gatos no 940.
Falando verdade sempre achei o meter do 940 pão duro na recepção mas pensava que era normal, escutava estação com

recepção boa e smeter ne se mexia. Acho que com esta modificação dos dois fet virando a 180º vai melhorar.
Você comentou que precisou ajustar o smeter do 0db, como faço para efetuar este ajuste.
Agradeço pela sua gentileza
Antonio PY2YW

From: de.marinis [de.marinis@globo.com]
Sent: quarta-feira, 10 de novembro de 2004 18:30
To: Eduardo Guisard
Subject: Re: Re:Dúvidas TS940S

Caro Eduardo de qualquer maneira acho que vou ver esta diferencia apos ter mudado os 2 fet, porque sempre achei o

s-meter do 940 pao duro, eu vejo isto quando faço dx com antena de 4 elementos da cruschraft cujo o
audio e 5 e o sinal de 0 nem se mexe o ponteiro.
O meu 940 é um dos ultimo da serie nao lembro onº de serie porque ele encontra-se na chacara a 100km de SP e

eu gosto muito dele.

Amanha estou indo para chacara e vou fazer esta modificação na terça apos do feriado te falo da diferença.
Acho que sem mexer no ajuste do s-meter nao vai afetar as modificações.
Abraço Antonio PY2YW

From: Larry Thomas [aa3px@nationi.net]
Sent: domingo, 14 de novembro de 2004 00:30
To: py1br@guisard.com
Subject: TS-940S Mods Questions

I can't believe this MOD. To think I loved this radio before it was fixed. Now it is even better.
Thanks

Larry Thomas
AA3PX
ARRL Technical Coordinator E. PA
570-204-0000 Work
570-799-0801 Home

929 old reading rd
Catawissa PA 17820

There is no known mechanism through which ordered complexity can arise from disorder by chance.

Where there is design....there you also find a Designer.

From: de.marinis [de.marinis@globo.com]
Sent: domingo, 14 de novembro de 2004 12:18
To: eduardo@guisard.com
Subject: Re: Re:Dúvidas TS940S

JÁ FIZ AS MODIFICAÇÕES E REALMENTE MELHOROU SÓ NÃO MEXI NO S-METER E

NOTEI QUE ESTAÇÕES LOCAL O PONTEIRO DO S-METER ENCOSTA NO FIM DA ESCALA,

MAS EU COLOCO O ATENUADOR

O MEU 940 E DE SERIE 9060282
ABRAÇO ANTONIO PY2YW

From: Yves CHARTON [yvecharton@wanadoo.fr]
Sent: segunda-feira, 15 de novembro de 2004 14:22
To: py1br@guisard.com
Subject: modification sur TS940
Bonjour,
j'ai bien repéré les deux transistors concernés qui sont bien sur mon transciever dans la position erronée

Comment proceder à la modification sans intervention et démontage qui apparaissent à première vue tres

importants et compliqués.
73 de F6IMI et F8ZQ
thanks in advance

From: marienve2ea [marienve2ea@globetrotter.net]
Sent: domingo, 21 de novembro de 2004 17:47
To: py1br@guisard.com
Subject: TS-940S Modifs Questions

Hi Nelson.

My call letters are VE2EA and my name is Marien.I have checked the errors you mentioned concerning

Q4 on the IF unit and 1/2 Q10 on the RF unit and effectively according to the schematic diagam they are in

the reverse position.What is amazing me is that I have checked the voltages according to the service manual

and the voltages are ok.Exactly like the manual.
I can't imagined that the voltages are OK and one of the fet's in the reverse position?
Could you light my light,if possible?
Thank you for your assistance.Yours truly.

Marien.VE2EA.

From: Anthony H Henderson [toyhen@yahoo.com]
Sent: segunda-feira, 22 de novembro de 2004 15:28
To: py1br@guisard.com
Subject: TS-940S Mods Questions

Ok,I was happy to get the information on the TS 940.
WEll my problem is that I have a receiver problem which I juse can seem
to correct and that is I don't get any signal from the antenna no out
putall I get is white noise...Can you sugest any thing that I can do to
correct the problem?I love my radio.(hi)

J73HA(Tony)

From: Anthony H Henderson [toyhen@yahoo.com]
Sent: segunda-feira, 22 de novembro de 2004 14:54
To: Eduardo Guisard
Subject: Re:TS-940S Mods Questions

Thank you for replying so quick,I will do like you say and get back to
you with the results.

Regards..
Tony(J73ha)

From: Jeff King [jaking@es.co.nz]
Sent: terça-feira, 23 de novembro de 2004 16:06
To: py1br@guisard.com
Subject: [Spam] TS-940S Mods Questions

Nelson,
Fascinating discovery. I have not had time to alter my TS-940 yet, but follow your site to see how others have
benfited from your research.
I have noticed that when compared with other radios that the 940 s meter does not respond until you get about

and s4 signal. That is the meter needle stays on the stop until the signal is S4, and then it jumps up.
Does this behaviour disappear after the mods, and does the meter fluctuate between s0 and s4 ?
The 2sk125 can be soured new at the following link.

http://www.donberg.ie/descript/2/2sk125.htm

I am astonished by Kenwood claiming your observation is not correct.
At the very least Kenwood should explained why.
Yours sincerely
Jeff King ZL4AI / DU7

From: IW2EN [IW2EN@HOTMAIL.COM]
Sent: domingo, 5 de dezembro de 2004 16:42
To: py1br@guisard.com
Subject: [Spam] TS-940S Mods Questions

hi

my name is john i write from italy
my call signal is IW2EN .

i have from some mouth a beautifull ts 940,it was of a om that have never used it.

i have look this thing.

when transmetting in fm or am and swecht the alc, the s meter go over fuul scale.
is normal this????????

in ssb mode no problem.
bye

regard gio

From: Luiz Alberto Leivas [py1pa@terra.com.br]
Sent: quinta-feira, 23 de dezembro de 2004 15:22
To: py1br@guisard.com
Subject: Dúvidas TS940S

ALO MEU CARO AMIGO NELSON,
PRIMEIRAMENTE GOSTARIA DE PEDIR DESCULPAS POR NÃO TER ME COMUNICADO

ANTERIORMENTE PARA AGRADECER A HOSPITALIDADE E DIZER DO PRAZER QUE TIVE

EM CONHECÊ-LO PESSOALMENTE.
COMO AS COISAS NÃO ACONTECEM “SEM SENTIDO” GOSTARIA DE INFORMAR AO AMIGO

QUE ACABEI DE COMPRAR UM TS-940 DO CLG PP9VR LEOPOLDO, E DEVE CHEGAR AMANHÃ.

LEMBREI-ME DO ARTIGO QUE VC PUBLICOU SOBRE ELE E ESTAVA LENDO MAIS ATENTAMENTE

PARA EXECUTAR ESTA MODIFICAÇÃO NO BICHO QUE ESTÁ POR CHEGAR.
MUITO GRATO POR TUDO E ESPERO RENOVAR O PRAZER DE REVER O AMIGO. RECEBA MEU

ABRAÇO E SINCEROS AGRADECIMENTOS PELA ATENÇÃO QUE VC ME DISPENSOU NAQUELE DIA.

DESEJO A VC UM FIM DE ANO MUITO BOM E PROMISSOR DE UM ANO NOVO CHEIO DE REALIZAÇÕES PESSOAIS.
73
LEIVAS
PY1PA

From: SLEDGEHAMMER5456@aol.com [SLEDGEHAMMER5456@aol.com]
Sent: domingo, 2 de janeiro de 2005 06:57
To: py1br@guisard.com
Subject: [Spam] TS-940S Mods Questions

i will like to know if all of the 940S have this problem, THANK YOU KB2QEI

From: SLEDGEHAMMER5456@aol.com [SLEDGEHAMMER5456@aol.com]
Sent: domingo, 2 de janeiro de 2005 16:01
To: eduardo@guisard.com
Subject: [Spam] Re: [Spam] TS-940S Mods Questions

my serial is 9020007 i was told that this problem was corrected on my serial number do you have any

more info on my serial number. thank you KB2OEI

From: Charles Kinsley [charliebrown@brightok.net]
Sent: domingo, 23 de janeiro de 2005 19:52
To: py1br@guisard.com
Subject: [Spam] TS-940S Mods Questions

Hey Guy
I read your artical about the 125's being backwards. Its hard to imagine something like that happening.
I changed mine. I have some other problems with my 940. The digital display will go off loose transmit
and recieve. The guy I bought it from had that happen to him too. He took it back to the factory.
I haven't seen anything in the upgrades that might solve this. It comes on some times and then goes off after

a little and then comes back on when it warms up. It usually stays on after it warms up. It will distort
receive and transmit untill it warms up. It started out doing this once in a while then quit for 5-6 months

then started again. It seems to be getting worse. I think it will quit for good before long.
Do you know any where to start on this problem. I sure could use a little help. I really like this radio.
I saved for a long time to buy this. I can't just dump it.
KB5RJM
Charles E Kinsley

From: n9bee [chash2@earthlink.net]
Sent: domingo, 13 de fevereiro de 2005 21:53
To: eduardo@guisard.com
Cc: chash2@earthlink.net
Subject: [Spam] TS-940S Factory Assembly Mistakes

I swaped the 2 fets and now everyone with a solid signal reads + 20 or better which confirms your corrections

-- I shall adjust the s-meter soon.... the audio quality also seems improved.
The rf agc setting may benefit with a touch up?
Thanks for the clarity and much improved rx on a rig with excellent tx which now boasts of equal rx It took

longer to r&r the screws and case than to swap the 2 fets.
Any other Thoughts on this rig???
Feel free to use this as a testimonial
Regards. N9BEE

From: solo22@sbcglobal.net [mailto:solo22@sbcglobal.net]
Sent: Saturday, April 30, 2005 12:21 PM
To: eduardo@guisard.com
Subject: TS-940S Mods Questions

Much thanks, Nelson, for sharing you interesting TS-940 mods. Since my '940 serial number is 20,500,098

(one of the last 940's made) it can be assumed ALL '940's have this flaw....mine did.
Looks like the "D" was printed on the circuit boards backwards, causing assembly techs to put the fet's in wrong

............nobody noticed until you came along 15 years after the type was discontinued.
I've been considering buying a new 756pro3 but now my '940's have a new lease on life. :-)
Thanks again, es 73, Ron K6ZL

From: ******* [mailto:christspi@hotmail.com]
Sent: Sunday, May 08, 2005 1:11 PM
To: Eduardo Guisard
Subject:

Bonjour Eduardo, je vous avis écrit il y a 6 mois environ lorsque mon ts 940 était tombé en pane.
Je suis Christian Spalvieri à Genève. Alors, j'en ai profité que l'appareil était démonté pour faire vos modifications.
Soit remettre en position normal les transistors. D'autre part, j'ai fait d'autre modification, comme celle de l'Alc changer

les condensateurs, et mis la puissance à 150 watts. Je peux vous dire que la réception est vraiment
extraordinaire. J'ai un autre poste, un icom 756 proIII. Le 940s est nettement plus agréable à écouter, c'est autre chose.

De plus c'est un appareil qui valait la peine d'être refait. En effet, il a très peu d'heure
d'utilisation. Lorsque je l'ai acheté à une femme radioamateur, il n'avait pas servi plus de 100 heures, il est comme neuf.

Dans tous les cas, je vous remercie de votre article, il m'a été très utile, et maintenant c'est un poste
au top niveau qui n'a rien à envier à un poste moderne. Je vous remercie encore Eduardo mes 73 très qro Chris

From: w0ebb [mailto:w0ebb@juno.com]
Sent: Thursday, May 12, 2005 2:23 PM
To: py1br@guisard.com
Subject: [Spam] TS-940S Mods Questions

I performed the same corrections to my Kenwood TS-940ST as noted in your article.
I found the same two transistors reversed on the circuit boards.
After reinstalling them correctly I also saw a 10 db of signal gain.

Thanks for the tip and finding such an obscure problem in an already great functioning radio.

Gary Auchard
Leavenworth Kansas
WB0MNA

From: Henry, Jim [mailto:jhenry@cbs.com]
Sent: Wednesday, June 15, 2005 1:37 PM
To: eduardo@guisard.com
Subject: [Spam] 940 fix

Thanks for the excellent info. I have two working 940’s and lots of spare parts. I checked all of
my boards and indeed, the 2sk’s are reversed on each and every board.
A question if I may, Does the 2sk device work properly after it is mounted correctly after many years of

being installed wrong? I believe that you imply that the 2sk works after it is mounted correctly.
Did you have to do a “realignment” to those stages after the reversal?
Thanks,
KF4IC

Jim Henry
Dir. Eng./I.T.
Infinity Orlando
WOMX / WJHM / WOCL
1800 Pembrook Dr. #400
Orlando, Florida 32810
407-919-1000

From: Bill Melody [mailto:bmelody@linkline.com]
Sent: Tuesday, July 19, 2005 12:33 PM
To: eduardo@guisard.com
Subject: Hello PY1BR

Hello Eduardo,

Thank you so much for all your work on the 940. I made the mods
to both Q4 and Q10 as you describe. My radio appears to be functioning
much better.I also had a bad relay in the attenuator and corrected that.
However after reading notes on another site:
http://homepages.ihug.co.nz/~jaking/TS-940_02.htm
it states Q10 was installed correctly from the factory and the schematic
is incorrect. Have you seen this statement from Kenwood?
I am totally confused about Q10.
Should I leave it as your mod shows or should
I out it back as the factory says?

I am also getting ready to do the VCO phase noise mod.
Have you done this mod yet? If so did you see any improvement?

Thanks ~Bill WA6YBD

From: RAULCREATIVE@aol.com
Sent: quinta-feira, 28 de julho de 2005 12:28
To: eduardo@guisard.com
Subject: Hello PY1BR

GRACIAS EDUARDO POR ESAS AYUDAS A LOS DEMAS COMO TECNICO LE FELICITO
AFICIONADOS COM USTED SON LOS REALES .

W2FR RAUL

From: py2yw
To: py1br@guisard.com
Sent: Wednesday, October 25, 2006 12:22 AM
Subject: Dúvidas TS940S

Caro Eduardo
A muitos anos que tenho um Kenwood TS 940S funciona perfeitamente e nunca tive problema a não ser a queima das lâmpadas do meter.
Tenho o manual de serviço com todos os "SERVICE BULLETIN" de modifications da Kenwood e meu radio não precisou modificar nada porque as modificações foram feita na própria kenwood de fabrica sendo o meu radio uns dos últimos de fato o numero de serie dele e:9060282.
Esta modificação, descoberta apos de quase 20 anos, me sta deixando com a barba branca.
Gostaria de saber se vale a pena inverter este dois FET? como mostra no site.
Apos esta modificação o que precisa mais para fazer as devida medição.
Sarei muito grato para este tipo de informação.
Muito obrigado
PY2YW Antonio

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