I had to "fix" a HP Cesium standard oscillator while on an SSBN.
The problem was a failed op amp in the control circuit for the crystal
oscillator.
Due to lack of parts, the "fix" was to run the standard open loop with
nothing controlling the crystal oscillator.
Using an oscilloscope to compare the good standard with the open loop
standard, I I was able to adjust the failed standard oscillator.
It took over two weeks of adjusting the failed standard oscillator to
keep the Lissajous pattern stable.
The oven was off for a total of less than an hour during troubleshooting.
Prior to failure the standard operated correctly for many months.
I was surprised as to the amount of time for the oscillator to settle down.
Glenn
On 11/2/2018 4:44 PM, Mark Sims wrote:
How long had the osc been powered up since taking it out of storage? It can
take an OCXO typically 4-6 weeks of constant power-on after long-term storage
before the drift settles down.
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--
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Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4...@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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