On 04/28/2016 02:45 AM, Alberto Rubinelli - Fondazione Museo del
I'm working at the power supply of a 990/5
minicomputer. The chassis
is a 6 slot version, with 20A power supply. After a few minutes of
working, the fuse blow and I found a transistor on the main power
supply board with collector in short circuit with emitter. The
transistor has TRW logo and is market with Texas part number
996070-003, in addiction with the date code.
I don't have a magic key to translate the house part number to something
real, but if I were to guess, based on the location of the transistor, I
suspect it's an NPN high frequency device. A good guess would be that a
"universal" TV horizontal output transistor might be a good candidate.
I've done that myself to old PSUs and it's worked well.
Try, say, an NTE238 or 2SC1308K or similar.