[time-nuts] Re: HP 5061A oscillator problem

[Bob Camp]

Hi

Worst case, there are ways to “kludge” a 10811 into the device. I suppose you also could go over
to one of the various 5 MHz OCXO’s that show up on eBay from time to time.

I’d pop open the 105 first ….

Bob

> On Sep 28, 2023, at 11:36 PM, vilgotch1--- via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> 
> H all,
> 
> I spoke too soon regarding the crystal oscillator in my 5061A. Disconnecting the fast warm-up heater only extended the time before it fails. There's obviously a temperature sensitive fault in there. I'll either have to try repairing it or find a replacement.
> 
> Morris
> 
> 
>> Hi all,
>> 
>> Since 2006 my in-house frequency standard has been a HP 5061A which still has a good physics package. I have retrofitted a Shera GPS system to it in the disused battery compartment and run it occasionally on the Cs to keep it nice.
>> 
>> Recently I turned off all lab power while I was away for a few weeks and when I turned it back on the 5061A wasn't working properly. It would start up and run for a few minutes and then the outputs would disappear. I have traced the problem to the 00105-6013 crystal oscillator unit and I think what is happening is that the rapid warm up thermostat is stuck on. When starting from cold it runs OK until the innards get too hot and then it fails. When I disconnected the AC feed to the rapid warm-up heater the oscillator runs properly and the osc heater meter starts at the extreme right end of the scale before slowly backing off over an hour or so and the oscillator unit feels warm.
>> 
>> What I want to know is:
>> 
>> 1. Is this a reasonable explanation and has anyone seen such a fault before?
>> 2. How long does the 00105-6013 take to get to operating temp using it's internal controller  without the rapid warm-up?
>> 3. Is the crystal oscillator unit repairable? I suspect a replacement thermostat would be unobtainable.
>> 4. Does anyone have a replacement 00105-06013 unit available? To my eternal regret I had a spare and sold it a couple of years ago. It just goes to show you should never throw anything out!
>> 
>> Thanks for your help and 73 to all,
>> 
>> Morris VK3DOC
>> Melbourne, Australia
>> 
>> 
>> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe send an email to time-nuts-leave at lists.febo.com