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Intermittent CCD Failures and Clock Signal Issues in LFC Camera - Troubleshooting Report

This report details the troubleshooting of LFC camera issues, specifically the intermittent failure of CCD#2 and recurring problems with CCD#5. Notable problems became more evident in October 2008, including bad images and a faulty parallel clock signal identified during inspection. Key actions taken included replacing the faulty clock board and adjusting gain settings for optimal performance. New issues emerged with regular spikes in image data for both CCDs, prompting further diagnostics and analysis to resolve the recurring anomalies.

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Intermittent CCD Failures and Clock Signal Issues in LFC Camera - Troubleshooting Report

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  1. LFC Troubleshooting Report G. Rahmer 2008-12-02

  2. 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.

  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.001.2.fits) Bias - November 28 (ccd.001.2.fits)

  6. CCD#2 Before and After (cold) Bias - October 26 (ccd.109.2.fits) Bias - November 28 (ccd.027.2.fits)

  7. 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)

  8. 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)

  9. LFC cold, 0s, 2x2 (before, on Palomar) CCD2 CCD1 CCD5 CCD4 CCD3 CCD0 /scr1/20081026/ccd.063.n

  10. LFC cold, 0s, 2x2 (after, in Lab) CCD2 CCD1 CCD5 CCD4 CCD3 CCD0 /scr1/20081026/ccd.063.n

  11. LFC cold, 300s, 1x1 (Lab) CCD2 CCD1 CCD5 CCD4 CCD3 CCD0 /scr1/20081201/ccd.012.n

  12. LFC cold, CCD3 (Lab)amplifier glow 300s, 2x2 0s, 2x2 0s, 1x1 300s, 1x1 /scr1/20081201/ccd.005-7-9-12.3

  13. CCD3, 0s, 2x2 (before and after) October 26 (Palomar) December 01 (Campus Lab) /scr1/20081201/ccd.007.3 /scr1/20081026/ccd.063.3

  14. CCD3, 300s, 2x2 (before and after) October 26 (Palomar) December 01 (Campus Lab) /scr1/20081201/ccd.005.3 /scr1/20081026/ccd.079.3

  15. CCD3 (Palomar, October 26) /scr1/20081026/ccd.079.3

  16. LFC cold, CCD3 (Lab, amplifier glow) /scr1/20081201/ccd.005.3

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