On 04/28/2016 02:45 AM, Alberto Rubinelli - Fondazione Museo del Computer wrote: > 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. --Chuck