Hi all,
This week I started having serious 15N pulse problems on our Inova 600. The first thing I found was the bandpass filter attenuating signals by >60%; I currently have a borrowed filter and am looking for a replacement (Agilent has some in stock; Spectrum Microwave no longer manufactures the original part).
However, my pulse width is still all over the place. I've checked inputs and output, and compared to other channels. The transmitter and attenuator boards appear to be working as expected; although there is a leading edge spike on the scope and the signal height (Vpp) bounces up and down a bit, it does this on both channels 2 and 3, and 13C on channel 2 is normal as far as I can tell. As for amplifier output, earlier in the week the gain was normal, but now the output power is higher (it's been lower at times). The input is if anything slightly lower but within measurement error from earlier.
I suspect this 14+ year old amplifier is dying. It's an AMT 9000-1 low band (6-220 MHz). I have at least 2 AMT 9000-12 amplifiers from an old Unity console; they have the exact same low band channel (and are of a similar vintage) and worked when decommissioned. The high band channel is the wrong frequency but isn't needed.
The question, for any with more experience than I have: would it be ok to replace the dying amplifier with one of the dual band units and just ignore the high band channel? If not, can I instead swap the guts of the low band channel into the the bad unit, or is there something else you'd recommend that I do?
I realize I could send the current AMT off for repair, but we all know how the money situation is these days, so if I can do something for free or barter…
Thanks,
Andrew
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C. Andrew Fowler, Ph.D. | University of Iowa
Associate Director | B291 CBRB, 500 Newton Rd.
CCOM NMR Facility | Iowa City, IA 52242
319-384-2937 (office) | 319-335-7273 (fax)
andrew-fowler_at_uiowa.edu
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Received on Sat Sep 22 2012 - 04:25:38 MST