[time-nuts] FTS 1000B instability problem.

[Angus]

Hi,

I have a problem with an old FTS 1000B from around 1993/4, and am
wondering if anyone here has any suggestions or can point me to any
info. 

The problem is just that it's much less stable than it should be - at
100s it's around 1E-11.
As well as general instability, it often drifts by 6 to 10 E-11 over
half an hour or so, often drifting back by the same amount a while
later. 
(At 1s it's worse than it should be, but not by very much, and long
term aging is ok)

The control/ref voltages on the buffer board are stable, as is the
oven temp. It's on a stable linear supply which has worked fine with
any other oscillator that I've tried on it, even if connected at the
same time as the 1000B - although each with its own filter.

I have a horrible feeling that it's just the crystal slowly dying, but
hopefully it's less terminal.


Thanks,
Angus.