In an effort to get more power out of the PMC, with the ISS OFF I tweaked the beam alignment into the PMC. Unfortunately I was unable to get any more power out of the PMC. Since the alignment tweak didn't help, I adjusted the operating currents and temperatures of the pump diodes for the 35W FE and the 70W amp (with the ISS still OFF). The thinking here is that since the power drop out of the PMC is not due to alignment, it's likely due to changes in mode content caused by the normal deterioration of the pump diodes. The changes are summarized in the below table.
| 35W FE | 70W Amp | |||||||
| Current (A) | Temperature (°C) | Current (A) | Temperature (°C) | |||||
| Old | New | Old | New | Old | New | Old | New | |
| D1 | 47.5 | 47.7 | 26.3 | 26.3 | 43.2 | 43.3 | 28.0 | 28.0 |
| D2 | 47.5 | 47.7 | 22.3 | 22.3 | 43.2 | 43.3 | 21.8 | 22.0 |
| D3 | 44.5 | 44.7 | 26.8 | 26.5 | 38.5 | 38.7 | 21.8 | 22.0 |
| D4 | 44.5 | 44.7 | 26.8 | 26.5 | 38.5 | 38.7 | 21.8 | 21.7 |
I've attached screenshots of the relevant PSL Beckhoff screen for future reference. After the above changes the 35W FE is outputting 32.4 W (was outputting 32.0 W before I started) and the 70W amp is outputting 68.0 W (was outputting 67.1 W before I started). I should mention that the 70W amp power is as read by the old HPO power monitor PD (H1:PSL-PWR_HPL_DC_LP_OUTPUT). I'm using this PD as I think something isn't quite right with the 70W amp power monitor PD; it did not register any changes in output power as I adjusted the 70W amp pump diodes (I'll look into this next time I'm able to go into the enclosure).
This adjustment increased both the transmitted and reflected PMC powers, but increased the transmitted more than the reflected (so moving in the right direction). I re-tweaked the alignment to try to lower the reflected power to no avail. At this point I think I will need to go into the enclosure to tweak the PMC up in order to impove the reflected power. All things said and done, with the ISS ON we now have 53.8 W transmitted through the PMC and 10.8 W reflected (when I started it was 52.9 W transmitted and 10.6 W reflected). So all in all, not too bad. Managed to get almost 1 W back in transmitted power and only increased the reflected power by 0.2 W. Because of this change in PMC output power I had to adjust the ISS RefSignal from -2.02 V to -2.04 V, which now has the ISS diffraction % at ~2.1%; this change was accepted in both the safe.snap and OBSERVE.snap SDF files.
In addtion, I reset both PSL power watchdogs at 17:52 UTC (10:52 PDT), thereby completing FAMIS 10727.
