[time-nuts] 5370A clock buffer board jitter/noise?

[Bob Stewart]

Thanks Magnus.  I see that parts for this board are only available from alternate sources.  So, I ordered an A8 board from ebay last night.  If it's no good, then I plan to replace U6, then U2, then U3 as soon as I can get the chips.  I feel like there's something wrong with the OXCO path, anyway, though it's also possible that the big spikes come from the 10811.

Bob
--------------------------------------------
On Wed, 3/23/16, Magnus Danielson <magnus at rubidium.dyndns.org> wrote:

 Subject: Re: [time-nuts] 5370A clock buffer board jitter/noise?
 To: time-nuts at febo.com
 Cc: magnus at rubidium.se
 Date: Wednesday, March 23, 2016, 1:09 AM
 
 Bob,
 
 While I don't think it may be the source of
 your 500 ps issue, if you 
 dig in the
 archive you can find a post where I disabled the signal 
 detect circuit which spews out 5 MHz spikes.
 It's a relative easy mod 
 and you can
 revert it, so that is at least one thing to test.
 
 Cheers,
 Magnus
 
 On
 03/23/2016 04:37 AM, Bob Stewart wrote:
 >
 I started getting noise spikes of up to 500ps on my 5370 the
 other day.  When I switch to external clock and use the
 PRS-45A, the noise goes away.  In fact, the noise issue is
 way better than with the 10811.  I swapped in a different
 10811, and the noise doesn't seem to have returned, but
 it was intermittent, so I may not have waited long enough. 
 However, even when the 500ps spikes aren't there, both
 10811s have too much noise, compared to the PRS.  So, is
 there some common cause for this on the clock buffer board
 that anyone's run into?
 >
 > Also, I did pop the bottom off the 10811
 from the 5370, and I noticed that the thermal fuse seems to
 have very thin wires compared to the socket holes it plugs
 into.  Could this be a source of additional noise?
 >
 > Bob - AE6RV
 >
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