LFC Troubleshooting Report

1
LFC Troubleshooting Report

• G. Rahmer
• 2008-12-02

2
The problem
LFC Focal Plane

• CCD2 reported as failing intermittently in
  August '08
• Bad images become more common in October. CCD5
  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 (CLK4-p1 -gtP0-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
CCD2 Before and After (warm)
Bias - November 20 (ccd.001.2.fits)
Bias - November 28 (ccd.001.2.fits)
6
CCD2 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 CCD2 and
CCD5 (not seen in others)
CCD2
CCD5

• 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
CCD2
CCD5

• 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