[Kenwood] Re: TS-830 unstable ALC and burned R37

[James Barrie]

I'm posting this as a FYI for all  ....
   IT  W A S  THE RELAY  ON THE AF  BOARD
Ok so iI tried to get the cover off of this thing and I couldn't do it. 
SO, I  set the spray can of DeOxit to heavy, pulled back on the cover 
as much as I could with a dental probe, and sprayed the hell out it 
right at the edge of where the cover and the relay meet.
I turned it on and it worked. Nice and stable ALC drive, with the grid 
going from -43.55 to  PLUS 4.56!!!!
The car control is now set at 3.5 ... never been that low. And 
microphone is setting is just 4. Got a great report on MIDCARS . In 
fact they had me back off the mike gain even more. Mike is the MC-60 , 
set at 500 ohms and the pre-amp OFF.

SO ...
I think we were chasing two problems. The burned up R37  on the RF 
board was the result of   R11 on the rectifier board going high. As 
soon I replaced R11,  R37 has stayed in one piece.
The ALC issue had nothing to do with R37 and R36... but everything to 
do with the relay.  I'd sill would like to know what was going on with 
the solder marks  I found where the relay is soldered onto the AF board 
...  and why R36  - a 1 meg ohm  R36 , not a 100k - was tack soldered 
in to begin with.... oh well. Since i am not the original owner, and it 
was bought from R&L, who knows.   But it works great now ...

Oh, and by  "we",  I  don't mean the infamous  ham radio 'We".
  Thanks to Ken, K4EAA who first responded and gave me ideas and a hell 
of a good, readable schematic.
Russ, WB8ZCC for more advice. He'll never read this since he doesn't 
have any Kenwood, but thanks anyway, Russ
  AND FINALLY Gordon, N6WK who endured something like 46 or so emails 
and responses over the last 3 or 4 days.  His patience and direction  
was really got my 830 s back and up and running. He did this while sick 
with a cold.
THANKS GORDON for all the support. I'm not the best tech in the world, 
but I do try. Gordon was REALLY patient LOL

73
Jim
WA8SD
On Feb 7, 2007, at 1:19 PM, James Barrie wrote:

ok, this is a continuation of the unstable drive issue with my 830.
  thanks for the advice on how to get to the bottom of RF board.
  I replaced the burned up R37 and the high R36 and fired up the rig. 
The unstable drive
  continued and while in the tune position, R37 went up in smoke again.
  Checked all the voltages on the 12BY7A while on receive and transmit 
and found the
  following:
  screen is 234 on receive and 191 on transmit
  grid : - 44.3 - receive and -4.93 to - 7.63 transmit
  cathode: ZERO on receive and 1.6 to 1.7 on transmit

  also checked R34 (99.8K), R41 (69.7), R35 (112.3) and R27 (387.9).
  The 12BY7 was tested good on a tube tester, but that may not prove 
anything ....
  Still getting 125 watts output.
  Anyone have any suggestions as to why the grid is not going positive 
and the cathode is
  not getting to 4.6v? Or is there another reason for the unstable drive 
and large current
  through R37?

  thanks,
  Jim
  WA8SDF