It turned out my friend was wrong. The power transformer is most likely ok. But one of the main choppers were short circuited (yes, it is a switcher, again to little info from my friend).
Anyway. The chopper transistors were TI made in 1978 but marked T484. Probably some IBM marking which no one has the cross for. I replaced them with nice high voltage high current TO3 transistors The only thing i could get from the original transistors except for the physical appearance was the polarity. With a 5.6 ohm resistor on the 5V i fired up the PSU with a 60W lamp in series with one of the mains leads. Nothing happened on the bases of the switchers until I got to around 190 VAC input. At that point the base went high and stayed there. Really strange. Of course I have no schematics for this IBM thingie. Does anyone have a schematic for the IBM 5110 PSU? I think I really need it to understand what is going on. Tracing it out is an option but then all those square metal canned IBM ICs... /Mattis
