LFC Troubleshooting Report G. Rahmer

2 The problem 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. LFC Focal Plane

3 Bad clock signal found Parallel clock P1A (CLK#4-p1 ->P0-p59) (low level floating) Normal parallel clock (not acquired at the same time)

4 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).

5 CCD#2 Before and After (warm) Bias - November 20 (ccd fits) Bias - November 28 (ccd fits)

6 CCD#2 Before and After (cold) Bias - October 26 (ccd fits) Bias - November 28 (ccd fits)

7 New issue: regularly-spaced spikes in CCD#2 and CCD#5 (not seen in others) CCD#5 CCD#2 Spikes spaced at app. 60 lines (2x2 binning) Time-invariant (same positions for different images)

8 Spikes in 1x1 binning are spaced at 30 lines CCD#5 CCD#2 Spikes spaced at app. 30 lines !! Expected 120 lines (as it is 60 pixels for 2x2 binning)

9 LFC cold, 0s, 2x2 (before, on Palomar) /scr1/ /ccd.063.n CCD5 CCD2CCD1 CCD3CCD0 CCD4

10 LFC cold, 0s, 2x2 (after, in Lab) /scr1/ /ccd.063.n CCD5 CCD2CCD1 CCD3CCD0 CCD4

11 LFC cold, 300s, 1x1 (Lab) /scr1/ /ccd.012.n CCD5 CCD2CCD1 CCD3CCD0 CCD4

12 LFC cold, CCD3 (Lab) amplifier glow /scr1/ /ccd s, 2x20s, 2x20s, 1x1300s, 1x1

13 CCD3, 0s, 2x2 (before and after) /scr1/ /ccd /scr1/ /ccd October 26 (Palomar)December 01 (Campus Lab)

14 CCD3, 300s, 2x2 (before and after) /scr1/ /ccd /scr1/ /ccd October 26 (Palomar)December 01 (Campus Lab)

15 CCD3 (Palomar, October 26) /scr1/ /ccd.079.3

16 LFC cold, CCD3 (Lab, amplifier glow) /scr1/ /ccd.005.3