Yesterday we suspected a large air leak at EY when pressure wouldn't drop below e-4 Torr with main turbo. Before pump down, we had valved in the new IP11+baffle and new HV NEG+housing into main volume in order to pump them out without needing separate pump carts. Valved IP+baffle out last night and the main volume pressure fell fast to normal levels in e-6 Torr range.
Today we found a large air leak in the chevron baffle nipple/housing measuring 5e-1 mbar-L/s, after finally bagging it. We also found a gappy mini conflat flange on one of the HV feedthrus that appeared to be the culprit until bag test on nipple. I was able to tighten the mini conflat metal to metal. It may have a small leak but with the other large leak it's too hard to tell until we separate them.
On Monday we will remove the IP and baffle and investigate. Hoping the baffle nipple leak is from a gasket and not a cracked weld. The new IP isolation valve allows us to vent one side up to air without interfering with main volume pump down.
Before leak checking, I assumed the gate of all-metal 1-1/2" right angle valve on top of IP was leaking because it seemed bottomed out (seals via knife edge) and the other side was up to air and closed off with a KF40. I replaced it with a new "easy to close" all-metal valve.
Note that I tested the newly rebuilt IP11 prior to installation next to beam tube. It shipped under vacuum with pinch tube and 16.5" blank, so I connected HV cables and turned ON without supplemental pumping. It behaved normal. If the mini conflat on feedthru leaks, it is likely small, but we will remeasure since I torqued the gappy flange.