[R-1051] 100CPS Synth

[John Schmitz]

Thought I'd give a quick update. Modification works........sorta.

I now have nice clean 100KHz injection to the translator with the 100CPS
Synth outputting a signal to the 100KHz Synth. Noise in the receiver dropped
right away, so I hooked up an antenna real quick and was getting AM'ers on
3880 very well. Problem is things are a little off Freq. 100CPS Synth should
be producing a 7.1000MHz or 7.1005MHz (corresponding to 000 and 500) to the
100KHz Synth. Signal I get there is several hundred hertz high and doesn't
change with 000 and 500 settings. Vernier works perfectly though. Further
sig tracing and signal checks is showing that I have both 1KHz signals into
IC1 phase detector on the 100CPS Osc Brd (A2) but TP1 just sits at +15v
(Vcc) no matter what the setting. I suspect I have a bad IC1 phase det on
the A2 board causing Q1 to sit cutoff all time and TP1 to sit at Vcc all
time. This is causing the varactors to sit max to one extreme all the time,
and the output to be sitting high all time.

Further supporting this assumption is that I discovered the non B chassis is
wired to supply +20v (when in Vernier) on line (J12 Pin 19). In the non B
version this doesn't go anywhere in the 500CPS Synth, but in the B 6-Pack
this is the loop control line that is only supposed to be at 4v. Basically
this put 20v on IC1 which is only supposed to have 4v applied. It's starting
to look like putting a B and beyond 6-Pack in a non B chassis could fry the
IC's in the 100CPS synth. I have no idea where I would find replacement
IC's, I'm sure they don't exist anymore. May just have to use it in Vernier
all time. Next I will try and rig test points to the circuit board and
actually check in/out signals and voltages right at the IC.

Al Parker, thanks for the schematic and servicing block, couldn't have got
this far without it.

John