[time-nuts] another Ebay mixup, 5370
didier at cox.net
Sat Jun 9 19:59:46 EDT 2007
One of my 5370A's had a severely distorted sine out, which Bruce helped me
trace to a bad solder joint on one of the cap that is part of the output
filter. After reflowing the solder joint, it all came to life with a pretty
good sinewave output.
Some of the caps on the amplifier board look different than most others. I
suspect they were maybe higher grade, but the leads must have been a
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Dr Bruce Griffiths
Sent: Saturday, June 09, 2007 4:55 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] another Ebay mixup, 5370
SAIDJACK at aol.com wrote:
> Hi Tom,
> this was the recommended setup (by HP) for checking the internal
> noise. Feed the 10MHz output back to the input using a short cable,
> and set the unit for "COMMON" input, setting 50 Ohm impedance etc.
> In the meantime I did some more tests, and found the following:
> 1) The sine-wave output is crappy. The sine wave has some sort of
> "Class-B" cross-over distortion, and it measures a whooping 200ps RMS
> jitter on my Wavecrest jitter analyzer (>400ps pk-pk). Compare that
> to 2.7ps RMS jitter I measure on our Fury 10MHz output. Definitely
> the crystal got damaged, or something else.
> The unit has about 2x better jitter performance (around 50ps RMS) if I
> feed a clean Fury 10MHz into it. I think the 10811 OCXO or the
> internal driver circuit may have gotten damaged.
Can you send an image of the rear panel sinewave output waveform?
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