[time-nuts] HP10811 losing EFC

[Bob Camp]

Hi

I sure would do some quick continuity checks on the EFC line before I started swapping varicaps out. A bum solder joint opening up is a lot more likely than the varicap going nuts in a fashion that still lets the oscillator run. 

Bob


On Jan 15, 2010, at 7:08 PM, Neville Michie wrote:

> 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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