Dear fellow NMR gurus,
I would like to solicit your opinion and/or advice on the following. An
issue has come up on my 1995 genre Varian Inova 500 spectrometer, and I
need to decide whether or not to convert it to a 3-channel system (from
a 4-channel system) and if so, things to watch out for in the process.
In my efforts to identify a "power drain" in my system, with help from a
colleague, I found that the 4-channel N-channel attenuator (NCA) has one
of its components (a 1 or 2dB attenuator) stuck in the 'on' position.
Thus I ordered a replacement NCA thru a 3rd party vendor.
Inadvertently, a 3-channel NCA was sent to me, and I did not realize the
difference until I took my 4-channel NCA out of the system. I decided
to go ahead and install the 3-channel NCA, to see if it would resolve
the power drain, which indeed it did.
However, my system is configured for a 4-channel system. It has 4
frequency synthesizers, two PTS 620s and two PTS 320s, and 4
transmitters, etc. Granted that the 4th channel likely has never been
used, and is definitely not needed by any of the current users. It is a
bit curious why a '95 500MHz system would have 4 channels in the first
place, though likely back then this was cutting edge technology. Also,
one of the PTS 320s is not functioning properly and when I measure the
Voltage coming out, it is wildly oscillating.
So, shall I officially change this system into a 3-channel system? Get
rid of the PTS 320 that isn't functioning properly anyway? This would
simplify some of the electronics. Although some questions come into
mind, such as what to do with the 4-way splitter (terminate one out or
get a 3-way splitter), then also what to do with the PTS bus cable
connector?
Have any of you done this with your system and if so, is there any
advice you have? Another option would be to get the proper 4-channel
NCA and leave the system as is, because... "why fix something that ain't
broken".
Your 2 cents on this one would be appreciated.
Cheers,
Monika
--
Monika Ivancic, PhD
NMR Facility Manager (A-212)
Department of Chemistry
82 University Pl.
University of Vermont
Burlington, VT 05405
(802) 656-0285 office
(802) 656-0279 NMR lab
Monika.Ivancic_at_uvm.edu
Received on Wed Jul 09 2014 - 10:23:31 MST