J. Oberling, F. Mera
This morning we swapped the failing laser in the ITMx OpLev with a spare. The first attached picture shows the OpLev signals before the laser swap, the 2nd is after. As can be seen there was no change in alignment, but the SUM counts are now back around 7000. I'll keep an eye on this new laser over the next couple of days.
- Old laser SN: 191-1
- New laser SN: 119-2
This completes WP 11454.
J. Oberling, R. Short
Checking on the laser after a few hours of warm up, I found the cooler to be very warm, and the box housing the DC-DC converter that powers the laser (steps ~11 VDC down to 5 VDC) was extremely warm. Also, the SUM counts had dropped from the ~7k we started at to ~1.1k. Seeing as how we just installed a new laser, my suspicion was that the DC-DC converter was failing. Checking the OpLev power supply in the CER it was providing 3A to the LVEA OpLev lasers; this should only be just over 1A, which is further indication something is up. Ryan and I replaced the DC-DC converter with a spare. Upon powering up with the new converter the current delivered by the power supply was still ~3A, so we swapped the laser with another spare. With the new laser the delivered current was down to just over 1A, as it should be. The laser power was set so the SUM counts are still at ~7k, and we will keep an eye on this OpLev over the coming hours/days. Both lasers SN 191-1 and SN 119-2 will be tested in the lab; my suspicion is that the dying DC-DC converter damaged both lasers and they will have to be repaired by the vendor, will see what the lab testing says. New laser SN is 199-1.
Noticing as the night progresses, the sum counts are slowly going up, starting from ~6200 and now ~7100. Odd.
ITMX OPLEV sum counts are at about 7500 this morning.
Sum counts around 7700 this morning, they're still creeping up
