[time-nuts] HP10811 losing EFC

[Bruce Griffiths]

There's no internal bypassing of the EFC line in the 10811A at all.

Bruce

J. Forster wrote:
> Here's a guess: Is there an electrolytic capacitor that bypasses the EFC
> to GND? Maybe that's bad. I don't have a schematic.
>
> -John
>
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>> Hi,
>>
>> I have two HP10811 oscillators that do not respond to EFC voltage.
>> The latest to fail had been quite accurately set against a TBOLT,
>> one morning (after being on standby in a HP5328A) it was off frequency
>> and would not shift with EFC but would adjust with the coarse adjust.
>> I have bought in two Phillips varicap diodes, BBY40 and BB149A,
>> but before I did some damage fault finding in the HP10811s  I thought
>> it wise to ask for any advice that was available.
>> While I am playing with them I may try to readjust the temperature
>> setting
>> of the oven to get on top of the turnover. Can anyone point me to
>> that article?
>>
>> cheers, Neville Michie
>>
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>>      
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