As promised, I received my replacement H744 +5V regulator in the mail last Tuesday. I haven't tested it yet, but it looks brand new. Other than that I don't have any more progress to report on the PDP-11, but a big project at work is just winding down, and I'm taking several days off next week. That will give me some time to really start tackling the power supply. I'll post pictures and updates here as I work on it.