Jason, Camilla, Fil, TJ

Last week Daniel found that the RF signal generator was outputting less dBm than it should, and swapping a cable from the N-type output to the BNC brought it almost back up (alog65171). Today we turned on the CO2Y laser to see if that helped bring our power closer to it's nominal value, but it only output ~10W not the expected 40-50W. We checked CO2X and it had approxiamtely the same power as before, 34W. This led us to think that perhaps there was an issue after the D1000124 RF distribution amplifiler where the signal is split to the X and Y lasers. We then checked along the path (block diagram) from the D1000124 all the way to the laser's distribution box. Both X and Y had the same values along this path and the same power going into them:

In mech room RF output 9.49dBm

In LVEA the input to D1000124 distubusion box is 5.3dBm: 8.3dBm with 3dBm attenuator 

So a drop of ~1dBm over the cable. 

Gives outputs of 9.8 - 9.9dBm on each output.

Removed 3dBm attenuator for 11.3dBm 8.3dBm into the D1000124 distrubusion box. 

11.8dBm out of each RF disrubunion box output channels. 

CO2X laser output  ~ 34W same as prev 1 month ago

10.6 dBm measured into sine to TTL generator

13.4 into CO2X on laser table  distubusion box 

CO2Y laser output ~ 20W slow at warming up

13.5 into CO2X on laser table  distubusion box 

While we were doing these checks, we noticed that the CO2Y power had "warmed up" to 20W over the last hour. This is unusual to warm up 10W, and trending the power output showed a varying output that we've seen with other lasers that are at the end of their lifetime. Many clues that all seem to point to an old, dying laser. Tomorrow we will swap in our spare unit, but we will need to start figuring out what we will replace these with in the long term.