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

[Barry]

Thanks, Ron.  Mine is a 100Mhz scope so if the problem is before the first few dividers, I'm not sure my scope will pick up a decent signal (perhaps a fuzzy line will at least be some indication of a signal).  There's not too much circuitry before the dividers so that shouldn't be too difficult to debug if that's where the problem is.

Regards,
Barry - N4BUQ

----- Original Message -----
> From: "KA4INM" <ka4inm at gmail.com>
> To: "Discussion of Electronic Test Equipment" <test-equipment at mailman.qth.net>
> Sent: Monday, February 9, 2015 11:56:10 AM
> Subject: Re: [Test-Equipment] HP 8640B Counter Not Working Properly
> 
> 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.
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