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LFC Troubleshooting Report. G. Rahmer 2008-12-02. The problem. LFC Focal Plane. CCD#2 reported as failing intermittently in August '08 Bad images become more common in October. CCD#5 is also reported as having problems, although not as severe. Camera is brought to campus in November 4th.
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LFC Troubleshooting Report G. Rahmer 2008-12-02
The problem LFC Focal Plane • CCD#2 reported as failing intermittently in August '08 • Bad images become more common in October. CCD#5 is also reported as having problems, although not as severe. • Camera is brought to campus in November 4th.
Bad clock signal found Parallel clock P1A (CLK#4-p1 ->P0-p59) (low level floating) Normal parallel clock (not acquired at the same time)
Actions • Replaced faulty clock board (SN269) by spare board from lab stock (SN336). • Replacement board required an adjust in the gain of volt ref op-amp to match original LFC board: changed R70 from 10 Kohm to 4.99 Kohm. • Will send faulty board for repair to Leach (if possible).
CCD#2 Before and After (warm) Bias - November 20 (ccd.001.2.fits) Bias - November 28 (ccd.001.2.fits)
CCD#2 Before and After (cold) Bias - October 26 (ccd.109.2.fits) Bias - November 28 (ccd.027.2.fits)
New issue: regularly-spaced spikes in CCD#2 and CCD#5 (not seen in others) CCD#2 CCD#5 • Spikes spaced at app. 60 lines (2x2 binning) • Time-invariant (same positions for different images)
Spikes in 1x1 binning are spaced at 30 lines CCD#2 CCD#5 • Spikes spaced at app. 30 lines !! • Expected 120 lines (as it is 60 pixels for 2x2 binning)
LFC cold, 0s, 2x2 (before, on Palomar) CCD2 CCD1 CCD5 CCD4 CCD3 CCD0 /scr1/20081026/ccd.063.n
LFC cold, 0s, 2x2 (after, in Lab) CCD2 CCD1 CCD5 CCD4 CCD3 CCD0 /scr1/20081026/ccd.063.n
LFC cold, 300s, 1x1 (Lab) CCD2 CCD1 CCD5 CCD4 CCD3 CCD0 /scr1/20081201/ccd.012.n
LFC cold, CCD3 (Lab)amplifier glow 300s, 2x2 0s, 2x2 0s, 1x1 300s, 1x1 /scr1/20081201/ccd.005-7-9-12.3
CCD3, 0s, 2x2 (before and after) October 26 (Palomar) December 01 (Campus Lab) /scr1/20081201/ccd.007.3 /scr1/20081026/ccd.063.3
CCD3, 300s, 2x2 (before and after) October 26 (Palomar) December 01 (Campus Lab) /scr1/20081201/ccd.005.3 /scr1/20081026/ccd.079.3
CCD3 (Palomar, October 26) /scr1/20081026/ccd.079.3
LFC cold, CCD3 (Lab, amplifier glow) /scr1/20081201/ccd.005.3