The first thing to be aware of is that the 9845A and the later 9845s (9845B abd 9845C) are _very_ different inside. All have 2 processors, and bus aritration logic to access the various ROM and RAM boards. In the 9845A there is, apparently, one PCB containing the 2 processor hybrid modules and a second PCB contianing the bus swithcing. In the 9845B and 9845C, there are 2 processor boards, each containing one hybrid circuit nad half the us switching logic. I therefore suspect yuor board with 2 hybrids on it is the processor board from a 9845A I've only been inside one 9845. That was a 9845B with the high speed language processor. In that machine, the PPU is a hyrid circuit on a PCB at the left side of the machione. The LPU is a set of 3 boards (basically bus interface, data path, control) with their only little interconnect 'backplane' at the top. One of the boards has edge fingers on the bottom edge, these plug into the main backplane, I believe in place of a single PCB containing a hybrid module for the LPU. There's some information on the 9845B on http://www.hpmuseum.net . There's an HP 'boardwapper guide' which might be useful, and some unofficial schematics of the 9845B and enhanced mono monitor (be warned it's _not_ a simple machine, I think there's a total of over 1000 ICs in that configuration) -tony