[time-nuts] Anyone familiar with SR-620 repair?

[J. Forster]

Not w/ that instrument, but try the following. I assume you have the book
w/ schematics.

Power the unit and with a DMM or VOM check the PS rails to see which is sick.

>From the book, locate all bypass caps on that rail.

Put your DMM across each in turn. The one with the lowest drop is likely
the culprit. If there is more than one w/ low voltage, it's likely the one
closest to the power supply.

You might try touching all the bypass caps to see if any are runni9ng hot.
This does not always work, because zero voltage or zero current dissipates
nothing.

-John

==============




> My SRS SR-620 counter died last weekend.  After superficial
> troubleshooting, it looks like there's probably a short on one of the
> power supply rails.  Symptom is that nothing lights up when power is
> turned on, but one or more of the three terminal regulators gets very,
> very hot (can't tell which one since they're all bolted to the side rail
> as heat sink).  The unit had been running continuously for several weeks
> when the failure occurred.
>
> I just learned from SRS that they charge a flat rate 25% of the current
> list price for repairs!  (To be fair, if you're the original purchaser,
> it's only 20%.)  The SR620 currently lists for about $5K, so we're
> talking about a mighty expensive shorted cap (if that's what it is)!
>
> Anyway, has anyone here troubleshot an SR-620 with a problem like this,
> or have any general insights about working on one of these beasts?
>
> Thanks,
>
> John
>
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