[time-nuts] Re: 5370A repair

[Wilko Bulte]

Power rail shorts are typically shorted tantalum caps. The yellow cylindrical ones are the most notorious for that, but other form factor Ta caps can also cause it.

Wilko

> On 17 Jul 2025, at 22:18, Tom Verbeure via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> On Thu, Jul 17, 2025 at 10:00 AM paul swed <paulswedb at gmail.com> wrote:
> 
>> Tom check to see if the 10 MHz feeds the 100 MHz multiplier. I think that
>> ultimately drives the system.
>> Without the board I think the clocks are missing.
>> 
> 
> Of course! I should have thought about that.
> 
> Right now, I don't even have anything on the "INT" or on the "EXT" test
> points on the A8 reference frequency buffer board. At least that narrows
> the issue down to this board only for now.
> 
> I don't see anything obvious on the board where a failure would result in
> shorting the +15V, but one useful thing is that the +15V is only used when
> there's an EXT clock in play. So I could disconnect the +15V (e.g. by
> removing R16 in the ripple filter) and then check if the INT clock comes
> through.
> 
> Thanks!
> Tom
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