[time-nuts] hp 10544A and 10811A ovenized oscillators

Glenn Little WB4UIV glennmaillist at bellsouth.net
Sat Nov 3 19:10:17 EDT 2018


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            wb4uiv at 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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