Should be a separate power circuit for the boards.
There are indeed two different circuits and this is so confusing to most people, they see the LEDs turn on and they think it's a confirmation that the PSU is in perfect shape which sadly isn't really the case.
I have another, a T17 that lost one (occasionly one more), but controler detects the faulty board, some data as voltage is shown
If I understood you correctly, you have another working T17 PSU (APW9) that is powering a single hash board, and sometimes two, and we know you "most likely" have a dead PSU and 3 working hash boards, wouldn't it be wise to take the working PSU and instal it on the "potentially" working 3 hash boards?
ill disassemble the psu to check if theres any visual damage, dont know anything about testpoints or so, would appreciate any suggestions for where to search.
We milked this topic quite a bit, but long story short these PSUs were not really meant to be fixed, it's not that it's impossible to fix them, but once you open it you will get the point, to me, anything except for a simple fan change on those PSU isn't working looking into, and I doubt you will find many resources regarding the subject, so if you are not an expert in this field, chances are you should be looking for a PSU replacement.
Now i changed the PSU took it from a working T17+. Same problem persists . Inotice this message in Awesom miner