[time-nuts] Ancient OCXO in scope calibrator.

David C. Partridge david.partridge at dsl.pipex.com
Tue Sep 9 16:25:09 EDT 2008


I checked all the solder joints in the area (to the extent of remaking
them).  Maybe there's a high resistance joint inside the mess of oxidised
shellac etc inside the OCXO.

Nuvistor is NOS, and I subbed another from my reserves just to be sure
(still in sealed plastic bag with perforated tear off to open) with no
impact on behaviour.

A ceramic alignment tool doesn't cause the same behaviour, but a probe sure
does.

D.

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of John Miles
Sent: 09 September 2008 21:08
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.

You might have an intermittent solder joint or component lead that's being
flexed when you touch various points with the probe.  Does a plastic
alignment tool cause the same behavior?

Or, more likely, there's so much loss in the circuit due to aging/component
failure that it won't restart oscillating on its own without going through a
power-up cycle.

-- john, KE5FX




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