MDM Trouble Report for 2007 Apr 22 Telescope: 2.4m Observer(s): Sharma & Statler (Ohio Univ) Instrument: 8k CCD Camera Problem(s) Encountered: Some difficulties with the 8k dewar continued. At 4:30PM we noticed that the pressure had risen to 2.7 mTorr-- that is, about 10.5 hours after the last liquid nitrogen fill. We refilled the dewar right away and the pressure came down to proper values. Filled again around 6:30, and this time made absolutely certain that it really was full and that we know how to tell the difference between full and not quite full. Made plans to refill midway through the night just in case. Around 1:30 we got errors from detcom during a readout, beginning as follows: Unsolicited garbage from 2nd Stray data from controller during exposure. Trying to salvage exposure. Hit abort if you want to start over. No data in 25000 msec Done writing file `HCG67v07.fits' Done writing `HCG67v07-B8.fits', linked to `~/current-B8.fits' 1st timing board passed data link test. 1st utility board passed data link test. 2nd timing board TDL failed (no response) 2nd utility board TDL failed (no response) We referred to the documentation on failing exposures. We tried but could not get a 'pof' to work: > pof High voltages disabled for 1st. no response from 2nd utility board (lub1 POF) `cmd lub1 POF' failed voltage rdmem failed for 2nd Failed to disable high voltages for 2nd. > 1st timing board passed data link test. 1st utility board passed data link test. 2nd timing board TDL failed (no response) 2nd utility board TDL failed (no response) > pof 1st utility board returned `ERR' `cmd lub0 POF' failed 1st controller target= 34.61+/-3.60 pon= 35.04 current= 0.03 1st controller target= 16.47+/-1.43 pon= 16.66 current= 0.02 1st controller target=-16.47+/-1.43 pon=-16.60 current= 0.03 1st controller target= 5.00+/-0.20 pon= -0.00 current= 0.01 Failed to disable high voltages for 1st. no response from 2nd utility board (lub1 POF) `cmd lub1 POF' failed voltage rdmem failed for 2nd Failed to disable high voltages for 2nd. Unsolicited garbage from 2nd: 2*words 0xFA8000 0xFFE400 ( ... ... ) We went through the recommended procedures in order and had success after version 3, in which we hit the two reset buttons on the back of Vesuvius. The startup messages from detcom were: source[1]: Now executing commands from `/home/vesuvius/obs24m/.director/startup ' starting agent `detcom /home/ccd/dsp/mdm8kltbmaster.lod /home/ccd/dsp/detcomlubACE.lod /home/ccd/dsp/mdm8kltbslave.lod /home/ccd/dsp/detcomlub.lod' CFHT Detector Host Command Interface, DetCom-MDM8K v.3.214 (Aug 30 2005) Copyright 1998-2001 Canada-France-Hawaii Telescope, Detected a GEN2 SDSU controller. 1st timing board TDL failed (wrong response) 1st utility board TDL failed (not all patterns worked) 2nd timing board TDL failed (wrong response) 2nd utility board TDL failed Unable to verify master/slave ID bits from ACE 7 retries needed while downloading to 1st timing board Engineering/safe mode. Use `power on' to enable high voltages. Filter is in position V (slot 2) New `observer' header will be `Sharma' New `object' header will be `HCG67' New `comment' header will be `April 22' Saving a single FITS file for each exposure. Following which operation returned to normal. At this point we also refilled the dewar, which took several (5?) minutes. Fortunately, the Dewar had stayed stable, and the pressure was at the nominal value of 0.0. The 8k continues to produce bad patterned noise which shows up prominently in the biases and in all data at low light levels, as we described in a previous trouble report. Later in the night (3:00-ish?) there was a 1-second interruption in regular electrical power. All vital equipment on UPSs kept working without trouble. ------------------------------ Submitted on 2007 Apr 23 [5:52:56]