Is lock channel tuning OK?
________________________________
> From: main_at_ammrl.groups.io on behalf of Beth Moscato via groups.io
> Sent: Thursday, May 22, 2025 11:35 AM
> To: main <main_at_ammrl.groups.io>
> Subject: EXT: [AMMRL] Avance I lock channel issues.
Hi
I’ve got an 400MHz AVANCE I console that is suddenly giving little / no lock
signal. I had very similar symptoms in April which I tracked down to a loose
2H_TR_J4 cable (jostled during other troubleshooting), but I am seeing identical
issues now which developed suddenly overnight (presumably without students
jostling the console).
Basically, when looking at the lock display, I see very little signal – when
I am unlocked and sweeping with my doped D2O sample, I am see maybe 4x S/N for
the sine waves even using the lock power settings for 90% H2O. Locking is of
course difficult or impossible under these circumstances.
The channel wobbs fine, and a pw90 on 2H yields 400us – slightly higher than
the desired 350, but not so high to explain the problem. Zg2h yields decent
signal.
I went and tightened all the cables on the LCB, R-TX, and L-TX boards. Several
are older and may be a bit frayed – I noticed that this was a problem earlier
this year.
All the lights on the LCB board are green, but the red “error” message
is also on. I can’t find the original AVANCE I LCB manual – I don’t
know what it means specifically.
Is there any chance there’s a repository of technical manuals for the AVANCE
series online somewhere, by the way? I’ve got a scope, but I don’t know
what power levels I should be expecting to detect.
Thanks for any advice,
Beth
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Received on Thu May 22 2025 - 10:14:36 MST