Hi Qi Zhao,
I have also had a very similar for almost 2 years now. Unfortunately, it first appeared a month after parts warranty expired but within service warranty. Nosiy wobb signal, lights on preamp staying on after pressing stop and not going off until "ii". And the local Bruker reps seem unable to solve it.
Be alarmed because the problem will gradually get worse.
When the problem first starts, it manifests itself as a noisy wobb signal. The "actual frequency" in the little pink text window starts to jump around. At this stage we can still run spectra OK. However, in a matter of hours or days or weeks, the noise gets worse and worse until you cannot see the wobb V at all. At this stage, you cannot get a FID - just noise and the "actual frequency" now jumps around by a few MHz. The problem was originally always with H and heteronuclei.
We found that if you turn of the AQS rack and then turn it back on, the problem goes away. It seems that the longer you turn it off for, the longer the problem goes away. But it always comes back eventually.
Bruker has tried swapping most of the boards and front cable in the AQS rack and has even charged us for one, but the problem still persists. The problem is independent of the probe.
Bruker's only suggestion was that we send the whole AQS rack to their office in Sydney. Since this was our only spectrometer and we could still manage to run spectra, we were very very reluctant to do so until we installed our 2nd spectrometer.
Unfortunately, last week the problem became permanent. First, only with the 1H (which was unusual) and then (a couple of days later) also with the heteronuclei. Turning the AQS rack no longer helps.
By the way, lock is still ok.
If any body else has had similar problems or knows of a solution, I'm sure we'd both be most interested to hear from tem.
Regards,
Julie
PS Thanks to everyone regarding their recent advice on running XWIN on the service licence. I will summarise soon and post.
Dr. Julie Niere
Senior Lecturer (Chemistry)
School of Applied Sciences
RMIT University
Latrobe St,
Melbourne Australia
>>> "Qi Zhao" <qzhao_at_tulane.edu> 05/20/05 2:04 AM >>>
Hi Every nmr Friends,
I meet a problem in DSX300. When I type 'wobb', the tuning curve in the curve in acqu window has very big noise. Due to big noise, I can not get a good match. But I can acquire H1 spectrum of water. How to deal with this problem. In addition, when type 'stop' to stop the wobb window, it is OK from windows. But matching and tuning lights are still shown on in the preamplifier. I have to type 'ii' to close it. It is not normal. What is wrong?
Thanks.
Best regards,
Qi Zhao
qzhao_at_tulane.edu
2005-05-19
Received on Sat May 21 2005 - 15:13:32 MST