Replacement for QP1008 (HP9816 PSU)

Err, no.... This PSU [1] has 2 transistors on the primary side. The chopper, component reference Q2, is a TO3 can marked 'QP1008'. There's also a current-sense transistor, Q1, a 2N2222 The latter is not a problem to replace. The 2N2222 is trivial to find, and it's not _that__ critical anyway. But the chopper transistor is almost certainly selected for some parameter, but I have no idea what (so that, for example, taking the chopper out of a good 9816 PSU board and sticking it on a curver tracer won't help, you don't know what you're looking for) [1] A Power/Mate EVD-6S-300S IIRC. And before someody suggests replacing the complete PSU, I should point out hat this thing has strange outputs. +5V (normal), +15V and -15V (or +14.4V, -14.4V?). The latter 2 are regulated down by linear regulator circuits on the monitor PCB to give +/-12V. [An aside for those who don't know the HP9816. It's a 68K computer with uilt-in monitor, although no built-in drives (those connect via an HPIB port). There are 6 PCBs in the case, and 2 expansion slots for HP DIO boards. Flat in the bottom of the case is the processor board, which contains the CPU, RAM (normally 256K bytes, it's possible to get 1M on there), boot ROMs, HPIB port, RS232 port, keyboard port, etc. THis plugs into a little backplane which carries the DIO slots On top of that, also plugging into the backplane is the monitor PCB, which contaisn the CRT drive circuitry and the +/-12V regulators) Plugged into that are 2 more boards of mostly digital ICs. The larger one is the text video circuitry, the smaller one the graphics video. And finally there's a metal box down one side of hte mchine (LHS seen connectes by 2 camels (mains in, DC out) to connectors on the monitor PCB] There are no HP part numbers on the PSU board components. -tony