[Heathkit] GC-1000 sure-fire repair

[Arthur Shulman]

I had the same problem with my 20+ yr old clock last year, and after
doing the repairs, it now works perfectly. I also has the symptom of
gradually reduced ability to update, with a final complete failure to
decode the WWV signals.

1)    Using a scope, check out the ripple on the low voltage power
supply lines, especially across the first large electrolytic cap. These
caps dry out and leak, eventually causing lockup failure in the PLL's.
Replace the 3 caps if a problem is found.

2)    Do a complete RF/IF alignment. The optimum IF freq might have
changed due to component drift. It was about 1 khz low in my unit for
best signal strength.

3)    Realign the 100 & 1000 hz PLL's with accurate audio tones & a good
low-level RF signal gen. The 2 pots should be set with the lowest level
RF sig that will provide lockup.

Since this was done, my clock is more sensitive & reliable than it ever
was when it was new!

Test equipment & the schematic are necessary to do the above. Off the
air signals are very frustrating to use if you try to do it that way!

Thanks to Don Peterson who helped me through the process.

Arthur Shulman VE3ZV