| DATE |
MAINTENANCE |
| 8 Jul 2004 |
displacers baked out, stage3 seal replaced at Hat Creek by Gary |
| 13 Jul 2006 |
dewar removed from C14 because Idrain=0 for WBA13
(problem actually caused by wiring error in dewar control box) dewar opened, checked, turbopumped, installed on C13 |
| 08 Nov 2006 |
dewar removed from C13 because 3mm SIS bias shorts out at elevations > 45 degrees |
| 29 Nov 2006 |
installed thermal stabilization plates on stage3 and mixer blocks shorted bias caused by wire rubbing against sharp edge of ground strap on mixer block vacuum baked displacers, replaced 1st, 2nd, 3rd stage seals replaced Scotch yoke Kap-Seal, but not the carbon bearings |
| 14 Jul 2008 |
opened refrig, replaced carbon bushings, Kap-Seal installed new dowel pins in valve clothespins vacuum baked displacers, replaced 1st, 2nd, 3rd stage seals - although seals were in good shape measured stage3 displacer: SS is 0.4956 dia, Envex is 0.4987 for most, 0.4978 at tip removed old 3mm mixer and HEMT, installed HIA-173 with WBA13 #169D |
| 17 Jul 2008 |
installed on C10 |
| 01 Jun 2010 |
removed from C10 dirty but not excessively so; stage3 seal looks good, but replaced; 2nd stage seal measures 0.053 to 0.063" thick, not replaced; stage1 seal not replaced; today I measure stage3 displacer diameters as, SS 0.4960, Envex 0.4990; |