Very good information, and spot on! The old guy here at work went digging through some old text books and found a couple articles on them including the SG series devices like the blown one, Surge-Gaurd circuit protection devices, NTC Thermistors just like you said. I already had checked the rectifier and it's a pretty beefy SOB and checked out fine, ie removed, meter tested, then hooked up elsewhere and load tested. I didn't check the filter caps though, hadn't thought much about them since again pretty beefy but for sure I'll look into those since it'll be a couple days for my FETs anyway. I understand there is a chance this PS might be a complete writeoff, it's for work though and I work for a power company so money isn't a huge deal and they've already ordered a new replacement PS to the tune of over $1K I believe... so this is kindof a play thing for me, if I can get it fixed/tested/working we'll throw it into stores in case of an extreme emergency we can use it. We use these power supplies for our data acquisition system at one of the plants, so really they would much rather replace with new then a reconditioned old unit... but again extreme cases have happened where a working rebuilt might be needed so it's a good thing to try and at least get it repaired