Hello,
This is a summary for my most recent query.
Thanks for helping out: Andreas Kaerner, John Grimes, David Live, Ivan
Keresztes, Jeff Simpson, Jerry Hirschinger, Chris Rithner, Martha Morton,
Thomas Dickinson. (hope I did not miss anyone).
Most people suggest RF interference which is not dangerous to the
instrument.
However some people suggested checking cables on receiver and between the
console and remote display.
Turned out that it was solids people poltergeist - when instrument was
converted back to the liquids setup blinking disappeared
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I would unplug the wires to the Receiver and plug them in again. If your
lucky, it is a contact that has loosened over time.
Otherwise, its time to get out the scope or get your electronics guy in
there.
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Try lowering receiver gain by 6db. type su
I've seen this when the console is in an intermediate state ( not setup
properly with the current experiment, after an aa or after a power fail
etc.)
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I see this as well, Evgeny, on one of my three Inova consoles. I've never
tried to track it down and it doesn't seem to cause any problems.
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Could it be that gain is latched high for some reason after an experiment?
What happens when you "su"?
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... we had 2 labs next to each other with a pair of 400’s about 15 feet
apart, separated by a wall. They were parked pretty close in frequency (I
forget the exact numbers). One would have a blinking rcvr overflow light
when the other was pulsing away in the lab next door. I never noticed any
problems with experiments but they were also walkup instruments only used
for quick 1D’s.
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I would suspect a bad cable between the console and the remote display. An
intermittent problem in the cable or connections could cause your symptoms.
I would at least check the connectors at each end of the cable, clean them,
and then reconnect. You could try flexing the cable at stress points to see
if the light flashing correlates to the movement. If you have another
Inova, you could swap the remote displays and cables to see if the problem
moves.
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If you have just interrupted 2H gradient shimming, the forward lock power
can get into the receiver and cause this to happen. If you load 1H observe
and type su, the blinking should go away (if the problem is from 2H rf
getting into the receiver).
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As I recall the lock signal comes in to the ADC module when the instrument
is idle. This is used for the lock scan function. If the input signal for
the lock is too big it can cause the overflow light to come on.
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Bet you have another instrument that's running a carbon with proton
decoupling. Do an acquisition on the blinking instrument with the pw set to
zero. Then look at the fid.
Thanks again!
--
Evgeny Fadeev, Ph.D.
Director, BioMolecular Spectroscopy Facility
1212 Natural Sciences 1
University of California Irvine
Irvine, CA 92697
telephone: 949-824-5842
http://www.physics.uci.edu/~biomolenmr
http://nmrwiki.org - Share your magnetic science!
Received on Thu May 06 2010 - 11:53:05 MST