| DATE |
MAINTENANCE |
| 29 Jul 2005 |
installed dewar10 on C8 |
| 8 Oct 2005 |
cold head ratcheting, on slow
or fast speed; motor blows fuses on compressor box; later, Mark
changed motors |
| 6 Feb 2006 |
replaced motor with another spare motor from Curt; decided that displacer was not able to center itself properly, which put too much force on the motor; cleaned displacers and cylinder but did not replace seals; polished displacer linkage sleeve to encourage displacer to center itself in the cylinder |
| 24 Feb 2006 |
lab tests after rotating 3mm pol; 1mm mixer bias shorted out |
| 06 Mar 2006 |
installed dewar10 on C12 |
| 05 Feb 2007 |
removed dewar10 fron C12; WBA13 gate bias seemed to be shorted; refrig running a bit warm (stage3 ~ 4K) |
| 15 Feb 2007 |
ultrasonically cleaned displacers in isopropyl alcohol, then vacuum baked 3rd stage displacer badly scuffed by seal; brass section also scraped near tip; polished most of the scratches off with sandpaper in the lathe; Bal-Seal jacket completely worn through on one side, spring wire worn - explaining scratches in displacer! replaced 1st, 2nd, 3rd stage seals, but did not touch scotch yoke bushings or valves |
| 03 Mar 2008 |
installed on C14 at Cedar Flat |
| 28 Apr 2010 |
removed from C14 at Cedar Flat |
| 24 May 2010 |
cleaned displacers and cylinder, replaced stage3 seal - worn through
to the spring in 2 areas; did not change stage1 or stage2 seals, or replace bushings or Kap-Seal;
2nd stage seal thickness is 0.057; measurements of stage3 displacer: SS seal rubbing area, 0.4961;
plastic, 0.4980-0.4990; brass tip, 0.4955-0.4975 |