Date: Mon, 8 Apr 2013 20:19:38 +0000
Dear AMMRLers,
Many thanks to Tim Claridge, Mike Engelhardt, Avik Mazumder, Tim Flood, Greg Heffron, Jerry Dallas, Sean Cahill, Jane Strouse, Martha Morton, Michael Goger, Thomas Dickinson, Bob Berno, W. Dale Treleaven, David VanderVelde, and Josh Kurutz (compilation of the answers below) for the suggestions of retrieving the lock signal lost upon switching fans on the AQS of our AV-300.
The original message posted on 2/27 was: "...I have a Bruker Avance II MicroBay 300-MHz whose systematic disruption of the communication between the console and host was traced back to overheating the CCU. I decided then to replace the fans of the AQS and, sure enough, three out of the eight fans were malfunctioning. My problem occurred in the subsequent re-positioning the AQS in the console's rack. After re-cabling the AQS the communication with the CCU was perfectly reestablished and is stable. However, I cannot obtain a lock signal. 1H and 13C are okay, I can even wobble the 2H channel. But the lock display does not provide the lock signal in the sweep mode. Has any of you experienced similar problem? Do you think soldering the connections of the fans on top of the AQS could somehow affect any of the boards, in particular, the 2H board? The system was working perfectly (with the exception of the communication) before their replacement. I am in touch daily with Bruker but, at this point, any comments or suggestions are more than welcome. The system runs Linux/TS 2.1.6."
After attempting most of all suggestions below, scoping various boards, and swapping three of them (2H preamp, 2H Control, and LCB), the problem was traced to a faulty TGPF0 connection at the back of the AQS rack on the Amplifier Control Board (ACB-S).
Thanks again and best regards to all,
Carlos
__________________________
Carlos Pacheco, Ph.D.
NMR Facility, Director
University of Connecticut / Department of Chemistry
55 North Eagleville Road, Unit 3060 - Room 002
Storrs, CT 06269-3060 USA
Phone:(860) 486-4069; Fax: (860) 486-2981
E-mail: carlos.pacheco_at_uconn.edu; Twitter: _at_UCONN_NMR
Webpage: http://www.biotech.uconn.edu/nmrf/
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We have seen the lock signal display disappear on various systems in the past- In all cases the solution was simply to disconnect the lock display output cable from the BSMS LCB board and reconnect (it is a serial cable connection). Starting TOPSPIN again then usually shows the lock sweep.
This may not be relevant in your case but could be the same problem so worth a try....
Good luck, Tim
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It's very unlikely that replacing the fans has an influence on the lock signal. The lock signal comes from the LCB or ELCB board via RS232 into the CCU and is routed back through Ethernet to the host computer. What may have happened is that one of the RS232 channels developed a problem, maybe due to overheating because of the defective fans. Have you tried to configure the lock on another RS232 channel?
Best wishes, Mike
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Loss of lock signal is a problem we faced in the past. The solution is as follows. After taking proper protection for static electricity we used to disconnect the lock cable from BSMS and re-connect it. We were able to get back the lock signal. Kindly consult your Bruker engineer before you try the same.
Best wishes, Avik
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We have had this problem twice in 4 years. Both times it was resolved by disconnecting the TTY lock cable from the BSMS/2 and then reconnecting it.
Tim Flood
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I am not implying that this is the case, but are you certain that the lock signal is not there? It is quite easy to miss this. Since I believe the lock boards are all in the BSMS and not in the AQS rack, it seems unlikely that an AQS issue would affect the lock. I would suggest that you verify that you see the lock pulse right before the probe. You can simply connect the cable that goes into the lock channel on the probe to a scope. This is low power, so no attenuator is needed. Turn the lock power up and look for the pulse. If you see it, it is very likely that you are not seeing it in the lockdisp because the field setting is wrong or the sweep amplitude is wrong or something like this. If you don't see the lock pulse, that is a different story. Because the wobb works, the receive side seems to be working.
This is what I would try. Good luck, Greg
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If you plug the lock cable into a scope you should see a low level square wave which is the deuteroum transmitter. I think the on/off rate is ~40khz. If you adjust lock power it should change amplitude. If you have no transmitter then you will not see a lock signal. Jerry
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Not sure if this relates to your system (we have an Avance DRX300 console): after cycling power to BSMS chassis and no LOCK SIGNAL was seen is LOCKDISP, we would have to disconnect/reconnect the AQX TTY03 cable (which controls the BSMS-Locksignal). Oddly enough, this would fix it every time!
HTH, Sean
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Assuming you didn't drop solder on some of the boards, replacing and soldering the fans should not have any effect on the correct functioning of the lock. I think you have just had an unfortunate coincidence of something deciding to go bad at the same time as your replacing the fans.
Jane
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Have you tried unscrewing all the wires on the L-TX and R-TX boards and reconnecting them. With the age of that console, I bet a wire is loose. Martha.
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I have experienced something similar on my AvanceI 500, fine lock signal before changing an SGU board, and then no lock signal after turning aqs rack back on.
We found the issue to be a loose connection on the TCU board, see attached pdf. On the TCU are three connections labeled A,B and C which are held in place a sort of thumb clip. In our case, for the A cable, the thumb clip is compromised and the A cable can be pulled out without holding the clip down, which we did not know until the above problem occurred.
What we found was that in our case this A cable was slightly dislodged, but small enough that could not be see visually. However, in desperation we checked all connections on the aqs rack and felt this cable re-seat and lock came back. We were able to repeat this observation several times. As best as we can figure that when we swapped the SGU board this cable must have been disturbed just enough to come loose.
Hope this is helpful. Good luck.
Best regards, Mike
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My experience here on our Bruker 700 is easily blown fuses. For some reason, Bruker consoles tend to blow fuses on power up. Check the PS LED's on the lower rack (LOCK control etc.) and make sure all the power LED's are lit properly. I've had to replace fuses in the rear of the lower card cage to get the lock working again. Good luck! Tom
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Try disconnecting and reconnecting the TTY serial cable assigned to the LockDisplay. It is often TTY03, but it could be any of them.
I have a much older AVANCE system where this communication problem with the Lock Display happens frequently. But because this system is usually solids, we don't worry about it.
Good luck. Bob.
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I am going to assume that you typed "BSMS" and (a) initialized the BSMS and (B) checked
the need to download any boards.My suspicion is that the tty port from which you detect your lock signal is either incorrect or
has "latched up". The first thing that I would do is type 'cf' to configure the console. Part
way through the process you will be presented with a window showing all of the tty
port assignments. First check to make certain that the lock cable does indeed go to the
port indicated on the screen. If the cable actually is connected to a different port than the
one shown on the screen, there is your problem. If the cable does indeed go to the tty port
shown on the screen, I would try moving it to an unused port, tty08, for example, making
sure to update the assignment on the computer screen and continue on.
I hope this solves your problem.
Cheers.
W. Dale Treleaven, Ph.D.
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Does the system have a lock switch, or a 2H TX board? Can you 2H gradient shim? It sounds like it's not getting the memo about switching between lock and 2H observe modes. Could any cables have been partially pulled off, not completely reset, or damaged during the maintenance? David VanderVelde
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As a matter of personal interest, could you please tell me whether you're able to view the status of the fans in the web interfaces that looks into the AQS? We did this sometimes on out Avance-III with TS 2.1.6, and it was helpful (at least it always assured the Bruker engineers who asked us to do it, though our fans weren't showing problems). I'm curious whether this interface works on an AV-II system.
If I recall correctly (and I don't have a console in front of me to check), the lock xmtr board has some kind of a channel selector dial that's used to match up the strength of the signal going out to the proper probe type (cryoprobes would need less power but use the same board). Could that have been misadjusted?
Thanks.
- Josh
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