These are examples of previously seen problems

Sudden and unexpected current draw seen on a feedthrough

As of 09/23/15 the known current draw on the feedthroughs in micro-Amps are (This is at +230 V / - 110 V nominal wire bias):

FT1 FT2 FT3 FT4 FT5 FT6 FT7 FT8 FT9 FT10
Positive Bias Current n/a 0 0 312 2 0 0 0 0 20
Negative Bias Current 0 0 0 0 0 0 181 320 98 1

If any of these channels were to change their state by greater than 6 microAmps the channel would go into alarm. This will not necessarily cause the channel to turn off (depending on the amount of increase in the current draw) but should give an alarm.

The alarm will appear with a given channel for the TPC bias current with red box as shown below

If this occurs, follow the instructions on the TPC guide and contact a TPC expert