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

Mike Feher mfeher at eozinc.com
Sat Nov 3 20:39:08 EDT 2018


Wow, I am surprised they allowed two weeks of playing around on an SSBN. I would have thought that on something like that the Navy would just replace it immediately. I was only in one once and I was real impressed by the professionalism of the crew. 73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115

-----Original Message-----
From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of Glenn Little WB4UIV
Sent: Saturday, November 3, 2018 7:10 PM
To: time-nuts at lists.febo.com
Subject: Re: [time-nuts] hp 10544A and 10811A ovenized oscillators

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





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