My ASX 300 has been exhibiting two (possibly related) problems. Bruker
has been very helpful, but I have run out of ideas and am looking for
new suggestions.
Problem 1: wobble is non-functional on both proton and X channels. On
occasion, the RG goes down and down, and after reaching 1, the error
message "signal too strong put in an attenuator" appears. Most of the
time there is no error message- instead the display shows a line with no
dip and very jagged, sawtooth noise. This occurs on both channels and
does not chage with wobble sweepwidth. It also occurs regardless of if
the cable is attached to a (known to be tuned probe) or a 50 ohm
terminator.
Problem 2: The proton spectrum has huge spikes. They occur at +/- 120
Hz (and multiples). They are bigger than a signal from a 5 mm tube full
of water (not D2O), about 1,000,000 absolute Bruker units. At this
point (see below) they are "only" 20,000 unit high- still too large to
accept. They are only on the proton side. The appear even if
everything (amplifier out, preamplifier in, cable to probe) is teminated
at 50 ohm. They do not change size with RG. They do not go away with
signal averaging.
PTS output looks good: .7-1.4 V f1 and f2 and the 10 MHz is 1 V at 10
MHz.
"tuning in" into preamp is 200 mV (same as measured a year ago)
syh and syx inputs to SE451 are 1-1.5V (didn't measure frequency)
Main power supply looks OK- voltages are about right and they have
100-200 mV of ripple.
The power supply in the Aspect 3001 has maybe 100 mV of ripple.
2 boards in the SE451 were swapped out
the entire SE451 was swapped out
the top section of the preamp was changed
all of the boards in the Aspect 3001 (except the "M") were swapped out
(before swapping boards in the Aspect, I replaced the two cooling fans-
the old were not working well)
End result: wobble is still "broken" as before
Proton spikes are smaller but still unacceptable.
At least one of the swapped boards in the Aspect 3001 is the wrong ecl.
I get an error:
"acqerrer: problems during MCI initialization channel3 bit 0
load/rewrite failed program stopped" This may or may not affect actual
running- but it didn't make ths spikes go away.
So,,,,, anyone have any great (or not-so-great) ideas?
Reply directly to me, please.
thanks,
kas
-- Karen Ann Smith karenann@unm.edu Manager, NMR Facility Adj. Asst. Prof. Dept. of Chemistry Clark Hall University of New Mexico Albuquerque, NM 87131 505.277.4031 url: http://www.unm.edu/~karenann An out of this world screensaver: http://setiathome.ssl.berkeley.edu/ "If you give someone a program, you can frustrate them for a day. If you teach someone to program, you can frustrate them for a lifetime."
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