[time-nuts] Another HP 5370B project

[Marc LeFevre]

I'm new to the list and just acquired an HP 5370B time interval counter
from eBay.  This instrument is nostalgic for me as I had one on my bench
working for HP out of college in 1981.  The listing for the instrument said
that it powered on but they could not test it.
My experience is that it powers on, tests the LEDs in the display, shows
0.0 for 10 seconds, and then gets an Err 02.
Combing through the list I knew to check a few things.  I reseated all of
the PCBs and I checked the relay K1 on A1 and found it in good condition
and working when I apply 24v.  I find that when I put in signals to Start
and End, the trigger LEDs flash but once Err 02 is displayed, the machine
is unresponsive until I power cycle it.