(Travis S., Gerardo M.)
Late entry.
Last Tuesday Travis and I troubleshooted the lost signal from HAM2 annulus ion pump.  Upon getting to HAM1/HAM2 the controllers for both AIPs were noted good, see photos, meaning that they both had a couple of LEDs on, this is good, then the connection for the signal cable on the back of the controller for HAM2 AIP was verified.  Voltage read zero when measured at the rack in the mechanical room, then the signal was measured at the controller but on the front panel, we got some sensible voltage ~1.4 VDC, so based on the results we replaced the controller, however that did not fix the issue with the lost signal.
After a brief break (went to X-End to install a fan motor on aftercooler for purge air system) and with a laptop on hand, the signal cable from the controller for HAM2 AIP was removed, I then noticed that the signal for HAM1 AIP went red, reconnected the cable for HAM2 AIP and signal for HAM1 AIP was back.  Long story short the signal cables never got switched, and with this new information I reseated the signal cable for HAM1 AIP, then the signal for HAM2 AIP was good, this was the loose connection, we still don't know why it lost connection, perhaps someone was up on top of HAM1 or in the vicinity shaking things around.

A FRS ticket is open to switch the signal cables at the rack 30026, since this is the easy way to fix this.