[Test-Equipment] HP 8640B Counter Not Working Properly

[KA4INM]

   On 02/09/2015 12:46 PM, Barry N4BUQ wrote:

> The counter on my generator shows all zeros (both in INTernal mode and EXTernal mode when connected via the front panel BNC jack).  I fed the external time-base (rear BNC jack) to a counter and verified 5Mhz is present there.

> My first step will be to verify that a signal is indeed making it to the counter board.  If that is present (and I assume it probably is), then I'll have to investigate the counter board(s).

> Is it a valid method to trace out the signal path with a scope?  In other words, I think I should be able to verify there are ECL-level and/or TTL-level signals along the path and at least be able to see if there's a point where the signal stops.  At that point, then I would start looking for bad components, etc.

> Is that a viable approach?  I assume that tracing this out with a scope probe won't give me false readings due to loading, etc.  Is that correct?

> Thanks,

   In my opinion yes, all you ask about is correct.
-- 
   Ron  KA4INM - Youvan's corollary:
                 Every action results in unwanted side effects.