Ibrahim, Oli, Betsy, Thomas

Today, we had a call with Thomas to diagnose LHO's QOSEM shorting issues - found in alog 90864, alog 90838, alog 90834. 

LHO broken QOSEMs:

S2600013 - Pins 23 and 10 grounded to chamber:

S2600025 S2600010 - Shorted (likely)

Tom's Suggestions On dead OSEMs

• Measure across anode -> cathode (two pins on end of flexi) and if it's working it'll be 1.6-1.7 V

On Sat Amp

• Grab multimeter, in current mode, connect to +/- and should see 35mA
• Plug any LED into satamp and check that they turn on

After the qosem broke, we swapped our last spare, requested more from LLO and carefully centered the QOSEM such that it's on the PD and roughly centered. Now, all our QOSEMs are working and are roughly (very roughly) centered.

Next:

We'll wait until the spare QOSEMs arrive to continue centering (now with a renewed meticulousness about shorting). Then, we can send the 3x broken LHO QOSEMs and 1x broken LLO QOSEM to CIT to Ali to resolder the LEDs and return them as viable spares.