[time-nuts] EIP545A 18GHz counter query

Chris Wilson chris at chriswilson.tv
Mon Dec 17 12:46:39 UTC 2012

> Me too.

> I have two 545A's, one of which works and the other of which has issues with
> Band 3, failing to read in a very interesting pattern suggesting a YIG
> filter issue, probably the control circuit.

> Just no time to chase it right now.

> Please post the resolution.

> Thanks.

> Joe

17/12/2012 12:31

Thanks to all who have assisted here, and in particular Paul Swed, who
via Skype helped me do the final de bugging, with expert knowldege and
good humour.. As requested the final resolution. The biassing of Q12
was critical and R54 had changed in value by some 25%. It should have
been 11k, but I only had a 10k, which got it counting correctly on
Band 2 again. I sourced the correct 11k resistors at 1% and also
changed R55 and the 10 ohm in the 12 volt feed. All seems well now,
although I have no means to check Band 3 above 1024 MHz, the limit of
my signal generator. Any ideas on getting a high frequency into the
thing? Hope this may help someone, the switching arrangement is a bit
odd at Q12, I think I know why, but won't cloud the water with
misinformation. Thanks everyone, have a good Christmas and a happy New

       Best Regards,
                   Chris Wilson.

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