hp proprietary uP history (9825 uP?)

I think I may well have that. On the left of my machine is a board with one of the HP hybrids on it. I assume it's a proccessor -- it looks very like the thing in my 9825 and 9831. On the right there's a set of 3 boards, only one of which goes into the main backplane. There's a little backplane on top that interconnects these 3 boards. One of them contains 4 2901 chips (4 bit bit-slice ALUs). Anohter contains what look to be microcode PROMs. I assume the former is the PPU, the latter the LPU. I would certainly describe my LPU as a bit-slice board -- do you know if the standard LPU was an HP hybrid chip, a board of bit-slice chips or what? I know little of the history of my 9845, other than when I got it it came with 2 8" drives, a few 16 bit parallel interfaces, 3 HPIB interfaces (!) a real time clock at least one RS232 interface and the rather hard-to-find 9878 expansion chassis. I know the 9825 hardware fairly well... -tony