[ARC5] Working on the AN/ARC-2

[David Stinson]

Having a problem with the Collins AN/ARC-2 transceiver.
On transmit, the PTO would drift up 1 KC+ over a few seconds.
First theory was that one or more caps on the various power 
busses
were leaking, dragging the buss down.

 Finally was able to get it on the bench last night and did find 
some.
The 260V buss that feeds the PTO is filtered by a large 5.5 uFd
oil-filled cap.  This tested "open" on my ZM-11, until I 
accidently
"popped" it with about 750V from the tester.   Now it tests Good
and I can't make it fail again, so I put it back in the circuit.
Anyone got a idea on that?

I also found two very familiar and very bad 5 uFd electrolytics
that were in the hash filter for the A+ buss into the dynamotor 
primary.
A bit surprised to see Collins using an A.R.C. Type-12 part:
http://home.netcom.com/~arc5/IMG_2904.JPG

All the other filter caps on the 260V buss check OK.
After "fixing" the 5.5 uFd, the PTO only drifts about 400 cycles
on key-down, so that was part of it.
Going to disable each stage on that buss one-by-one
until I find the "bad boy."

Working well enough now that I was able to work
W1AW/7 on 3885 KC AM with it last night.
And I beat-out a local friend in the pile-up
with his Ground-Pounder BC-610E... heh heh!

GL ES 73 DE Dave AB5S