Based on experience with my AV-I vintage systems in the past, the problem
could be in equal part on 'transmit' or 'receive' side. In my case, it was
the HPPR 2H slice. As others in the group by now are thinking and
suggesting, it is a good idea to start with the L-TX output and see if you
have linear behavior of the amplitude. You can then move to the receiver
side of the picture. In the 'Locked' mode, the LCB sends a 2 kHz pulse
train (more like a Sine shaped pulses), it might be easy to see on the
scope with the Lock set to ON rather than in Sweep mode.
Best
Rajan
On Thu, May 22, 2025 at 9:52 AM Beth Moscato via groups.io wrote:
> 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
>
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#2363): https://urldefense.com/v3/__https://ammrl.groups=
.io/g/main/message/2363__;!!PvDODwlR4mBZyAb0!Q3_mlg2lGLV8B1GaKPsWyGEwjhy7aK=
lwN_1JFOd-jn83EK_k2YK5wJAOLq3MwBMl6NJ45UQ8WnLqR7cAYgdlArBE$
Mute This Topic: https://urldefense.com/v3/__https://groups.io/mt/113250817=
/7559972__;!!PvDODwlR4mBZyAb0!Q3_mlg2lGLV8B1GaKPsWyGEwjhy7aKlwN_1JFOd-jn83E=
K_k2YK5wJAOLq3MwBMl6NJ45UQ8WnLqR7cAYqLcRt0J$
Group Owner: main+owner_at_ammrl.groups.io
-=-=-=-=-=-=-=-=-=-=-=-
Received on Thu May 22 2025 - 13:01:31 MST