Re: [AMMRL] Varian Ref Gen Board MR400

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 outputin order to continue testing and troubleshooting.

 

Any advice would be appreciated!

 

Thanks,

Uddhav

 

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