dear you all,
there is a strange lock fault in
our drx500 spectrometer:
in lock mode the lock signal is unstable
with some little drop-downs and unregular
drift-ups and drift-downs but only with moderate noise.
(haha, very interisting. could be everything on earth)
but:
in no-sweep mode (lock off / sweep off) there is
an about 0.25 hz oscillation visible (frequency is considerably
lower than the sweep wiggles) with an irregular amplitude of
about a quarter of the lock display grid.
disconnecting the transmitter wire between bsms and hppr or
between hppr and probehead makes the the lock baseline jump
(like a change of lock dc) and makes the oscillation diappear.
there is an over or undershoot when disconnecting these wires
with additional wiggles.
replacing these wires or the deuterium rec connection
between hppr and lock didnt change anything but the lock dc.
the unstable lock makes proton spectra look like sh..
but not very specific: bad linewidth and -shape,
sometimes dispersion artifacts and so on.
what we have already changed without succsess is:
- all three shim boards (shim current logic/amplifiers/stabilization)
- shomandl (crystal oven/frequency reference/synthesizers)
- one lock board
*** what may be the reason, have you seen that before? ***
*** have you any idea how to spot the fault? ***
*** can we check somethin while deuterium wobbling? ***
cheers,
rob.
(i will tell you about any success)
Robert Meinecke
Research Group of Prof. Dr. B. Meyer
Institute of Organic Chemistry
University of Hamburg
Martin-Luther-King-Platz 6
20146 Hamburg / Germany
Phone +49(0)40-42838-4361 or -4309
FAX +49(0)40-42838-2878
Email: robert.meinecke_at_sgi1.chemie.uni-hamburg.de
http://sgi1.chemie.uni-hamburg.de
Received on Wed May 21 2003 - 14:52:24 MST