[Kenwood] TS-430S problem

[Rob Stampfli]

On Wed, Jan 07, 2009 at 09:52:55PM -0500, Everett Swift wrote:
> Hello,
> I need help with my TS-430S.
> It receives fine but when I transmit the transmit power starts out at 
> 100 watts with a rapid fluctuation of a few watts, after a second or two 
> the wattage swing gets larger and the power slowly drops to nothing.
> The Final heat sink gets warm and the fan kicks on.
...
> I cant afford much money, I got my License a month ago and spent every 
> thing I could afford on this radio, tuner and power supply.
> 
> But If you know of anyone who can fix it and not charge $50 an hour let 
> me know.
> 
> Thanks,
> Everett Swift
> KD8JWJ

Everett,
This sounds like it might be what is a fairly common problem with early
TS-430S units.  If it is, the fix is fairly simple and essentially free
it you care to tackle it yourself.

On the finals board of units manufactured in the first year or so,
Kenwood used some pass-thru rivets that over time developed a resistance 
and caused power fluctuation problems.  They later soldered these rivets
to prevent this failure mode.  You can take out the board and do this
yourself -- and you'll have to if the transistors themselves have been
fried because of this problem -- but that is a pain and there is an
easier workaround if the drivers are still good.  Richard Measures, AG6K,
came up with an alternative fix that worked for me.  Go to:

http://www.somis.org/430.html

and search for "loss of power" for Measure's description and his solution.

Good luck,
Rob