MDM Trouble Report for 2010 May 22

Telescope: 2.4m
Observer(s): Statler, Hawkins (Ohio Univ.)
Instrument: Direct/Echelle

Problem(s) Encountered:
Evening bias frames were fine, but at first twilight flat, images
were filled with a non-repeating pattern looking like a cross between a
bad plaid and a Navajo rug. This may be the same thing Thorstenson
saw earlier this month. (We had seen it on single frames occasionally
on the last 2 nights.) This persisted and we could get no
uncorrupted data. Tried hitting the reset button on the Echelle
electronics box but that didn't work. Called Bob, who recommended
after some troubleshooting that we cycle the power briefly. Did this
twice but with no good results. Bob then recommended shutting the
power off and leaving it for half an hour. This cured the problem.
When bringing the camera back up we saw that the electronics board
temperature was increasing. Scrolling back through CCDCOM output
we saw that it had previously been above +30 degrees. We kept
a watch on it during the night but it did not go above +25
degrees. No other problems during the night but I doubt that
this was a genuine fix for the root cause.

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Submitted on 2010 May 23 [5:20:07]