Date: Tue, 07 Oct 2025 06:51:43 -0700
Dear All,
Does anyone have a working spare Varian - Agilent MR400 Ref Gen Board (80 MHz)
Part Number 01919958?
We started seeing noise in the 1H tuning window in early May this year
(attached pictures). which led to noise in the baseline of nmr spectra. We
thought the console was overheating and we took the side panel of the console
out and cleaned the mesh filter in the console. We also installed two larger
fans below the ref gen and synth boards. This helped for a few hours (noise
reduced) but reappeared overnight. After asking Agilent about this
issue, they said it was the ref gen board going bad.
We got a replacement board from Agilent in June, which worked fine for a week
after which the noise appeared again. After a couple of weeks week or so in
the end of June, the tune noise worsened (pic attached).
In July, since Agilent did not have another working ref gen board in stock,
we were able to obtain another board from a third-party source. Upon installing
this board and starting up the console, we were unable to see a connection at
all with the spectrometer: could not tune, could not connect to the VT system.
At this point we measured the output from the ref gen board, but got no clock
output in the oscilloscope.
We then reinstalled the Agilent board again but got similar behavior (the system
was not connecting at all).
This is where we're at now, we have two non-working boards and Agilent told us
in order to figure out the original issue (tune/baseline noise) we would still
need a working ref gen board and clock output in order to continue testing
and troubleshooting.
Any advice would be appreciated!
Thanks,
Uddhav
Uddhav Kanbur, PhD
Chemical Instrumentation Facility
Iowa State University
2438 Pammel Drive, Hach Hall 1234
Ames, IA 50011-1079
uakanbur_at_iastate.edu
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(image/jpeg attachment: RefGenBoard.jpg)
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