[Kenwood] RE:TS-940 What is the correct FET direction?

[Garey Barrell]

Jeff -

OK.....  Just in from Kenwood...

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Dear Kenwood Customer:

This information pertains to the TS-940S component location.

The circuit designer said the installation of Q10 in the actual TS-940S
transceiver is correct. 
The PCB view in the Service Manual is correct too. 
The schematic is the only section that is in error. The schematic
indicates the drain of one FET connected to the source of the second
FET. The correct installation is to have the source of one FET connected
to the source of the second FET. 
In addition, testing at Kenwood Communications in Long Beach, CA showed
poor results. Sensitivity can become unstable. 
The most important point about the Q10 pair is that both FET's must be
replaced at the same time (like a matched pair). Replacing only one FET
at a time can affect sensitivity.


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

Sincerely,

Kenwood Amateur Radio Customer Support 

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73, Garey - K4OAH
Atlanta

Drake C-Line Service Manual
<http://hr99.home.mindspring.com/R-4C_Servicez/>



Jeff King wrote:

>Rob,
>
>Thanks for your interest.
>The original FET posts are:
>
>www.guisard.com
>
>http://www.eham.net/articles/9261
>
>Read them in this order.
>
>My sketches of the drawn out board circuit are not good enough quality
>to post, and I do not have time to re-draw them right now.
>
>If you take the circuit diagram in the Service Manual and re-draw out
>you will see the FETs are indeed the reverse way around. 
>
>Yours sincerely
>Jeff King
>
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>
>  
>