It's fixed, a new day respite helps. Previously I noticed that the
component board had been removed at some time becasue I could see signs of
resoldered wires on the non-component side. (At that time I found a cold
solder joint on R231.) I thought perhaps a wire had come off or someone
transposed some. Being lazy I got the high intensity light out and thought
I could see if there was a problem without taking the board out, there's
only 4 screws! But before doing that I thought I'd recheck the 10K ohm Gm
bridge resistors, pot and as I was connecting my Fluke to the10K resistor
lead I could see it was wrapped around the post but not soldered, same for
all of them. Eureka and happiness, good light helps. I took a pix and posted
it at alt.binaries.pictures.radio. I soldered 4 ends and now it works like
a champ and checks a known good 12AX7 as good. No more meter slamming
backwards on Card 9 or power kick off and the Lo Gm pot works per spec.
After more careful inspection I could see where others have tried to repair
this one because I could see other signs of soldering and component
replacements, some not so good. Since it was like this from the factory,
it had to have been continually intermittent and became a waster of gravity.
Anyway I'll be it didn't get much use and I think the condition of the
switch matrix with all the waxy stuff was becasue it was sprayed trying to
solve the no solder problem. This one is Serial No. 703 so if you have one
near that you might want to check R 402, 403, 404, and 406 for no solder!
73
hank wd5jfr

"Henry Kolesnik" wrote in message
...
I've got one of my Hickok LS 15874 L2 Cardmatics going. I cleaned, lubed
and realigned the switch matrix as well as other switches and also found a
cold solder joint from a previous repair. About 100 of the switch matrix
pins had what looked like old paper capacitor wax on them, very sticky! I
took all the pins out, cleaned each one and the sockets. (An ultrasonic
cleaner would have been nice.) It took several attempts to get the
clearance correct, since the jam nut moved but I finally figured out a
system. Now it appears to test tubes just fine but it still has one
problem
that escapes me and wonder if anyone would have any ideas. It responds
per
the manual to all test cards except card 9, Gm, Low Ib. About half the
time
card 9 will kick power off and I'm guessing it's because the meter kicks
backwards below zero when button 2 is pressed When it doesn't I can
adjust
Low Ib per the manual and seems to work fine. However sometimes the
meter
needle doesn't go below zero enough to kick the power out but when this
happens the Ib control has no effect! Any ides or tips appreciated.

73
hank wd5jfr