J. Warner, R. Schofield, (J. Kissel remotely)

Jim called me this morning around 10a PT informing me that the ETMX ESD was unresponsive, preventing any lock re-acquisition. We eventually found that one leg of the HV power supply to the HV ESD driver at EX was off; unknown as to why. I reminded Jim how to restart it, then the ESD driver came back to live as normal after hitting the ON/OFF button on the HV ESD driver itself (no need to disconnect/reconnect any cables this time).

Diagnosis timeline:
I logged in an found that the HV monitor channels were all zeroes in the bottom right corner of the SUS ETMX overview, even though the digital request was the usual large bias and linearization voltages on the signal quadrants. I also noticed that because these monitor channels were reading zeros, the ISC_LOCK guardian -- which was in the DOWN state -- was hammering the remote ON/OFF button (I thought we fixed this??). After requesting that the ISC_LOCK just CHILL (i.e. pausing the guardian node), I waited a bit to let the HV ESD driver's internal mirco-processor relax then tried to remotely restarted it again. 
No dice. 
I advised Jim to head down to EX so we could debug together there (he'd gone with Robert). He went immediately to the VEA to try the ol' plug-un-plug cable trick, and found that the physical ON/OFF button did nothing, and that some indicator lights had shown that a leg of the 430 V input was red / dark. So, "we" went out to the entry foyer where the two HV power supplies live, and he found one off. We turned it back on --
 - Flip the rocker switch up to ON (wait for boot cycle to complete)
 - On the keypad, type
    - VSET > 430 ([V] for the amount of output voltage) > Enter
    - ISET > 80 ([mA] for the internal current limit) > Enter
    - Output ON/OFF
and then Jim went back out of the floor, the ESD HV driver looked much more lively, so he hit the button and the box came to live and I saw the voltage monitor channels go to their usual values. 

The only thing I can think of that trips the HV power supplies for the ESDs is the vacuum system (and when it does, it usually trips both), so I did a cursory vacuum system check on the EX overview screen, and didn't see anything crazy (i.e. I saw a bunch of green lights, and both vacuum Pirani gauges were sitting happily at ~1e-9 Torr. We'll debug more on Monday when I don't have to use the fragile remote connection to CDS.