Re: [AMMRL] 400 MHz Avance I data acquisition issue

From: Michael Groves <m.groves_at_utah.edu>
Date: Mon, 15 May 2023 15:34:32 +0000

Hi David,

I second the “check the fans” suggestion below. Insufficient cooling can cause weird things. I have a couple other things I would check.

You might check the voltage at the wall that is being supplied to the instrument. And make sure the switches on the back of the AQS and BSMS racks are set accordingly. Sometimes voltages drop in the summer and this can cause weird effects. A picture of the “strange erratic spikes” in the lock signal might provide some indication of what’s going on.

One board that is common with the acquisition hardware and the lock is the REF-22 board (I think that’s the right one for an AVI). Maybe that is intermittently crapping out and causing some weird timing error in the acquisition hardware and causing the lock to drop out.

And one more thing that sometimes improves things but it’s kind of voodoo… On systems of that vintage there have been cases where the system was powered off, and the boards in the racks loosened, un-seated, and re-seated. And this has helped. I think the theory is that sometimes oxidation can build up on the contacts and re-seating the boards improves the electrical contact enough to solve the problem.

Cheers,
Mike

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From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> On Behalf Of Spin-Doc
Sent: Monday, May 15, 2023 2:23 AM
To: main_at_ammrl.groups.io
Subject: Re: [AMMRL] 400 MHz Avance I data acquisition issue

Dear David,

did you check the fans on top of the AQS rack already? Could be some boards are overheating from time to time…

Best regards
Bert


Am 15.05.2023 um 05:19 schrieb daveonofrei_at_msn.com<mailto:daveonofrei_at_msn.com>:

Hello all,

I'm really happy with the new home of this group since I think this makes it much simpler to ask questions and search for previous solutions to problems.

I'm having a recurring issue with my 400 MHz Bruker Av I which works wonderfully except for a recurring and sporadic issue that has been happening for a long time. Data acquisition (even on 1D spectra) only partially acquire and I get an error that is always some variation on "zg: rcuerror: Scan speed overrides accumulation Increasing DW or D1, decreasing TD or switching off the FID display may help fifo cycles: 191 done, 66 missed, Lock anomaly during acquisition". This usually means that the acquisition only collected part of the data, and then "something" prevented it from finishing.

The number of cycles finished/missed varies and sometimes this is accompanied by strange erratic spikes in the lock signal that persist even after acquisition has been manually stopped. I have replaced many boards on the AQS rack in pursuit of this white rabbit (specifically the TCU, RCU, GCU, and even one of the PSU units on the back) and while the frequency of the problems seems improved, it still happens randomly.

Overall, acquisition still works ok with fewer NS and a TD0 of 4 (writes NS to disk for 4 loop.) That way some of the data is saved and processed. Otherwise it loses all the data. But I'd like to get to the bottom of this. Does anyone have any insight about what I might do to fix this issue once and for all? 1H spectra look really good on this system when it works and it's the only instrument with an autosampler so it's used for high throughput and really a pain to have to keep dealing with this. I wanted to keep this short but if anyone needs more information about this specific issue let me know.

Best,
David O.


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Received on Mon May 15 2023 - 09:07:50 MST