HP9845 service toolkit

[Eric Smith]

Tony replied to my comments about the HP BPC processor in the 9845:
> I haev one of those. I don't think it's the same device -- exactly -- as
> in a 9825, it appears to have more connections for a start. It is almost
> certainly the same architecture, though.

The full processor is a three-chip hybrid.  But in some cases they
use only the main processor chip.  That's what's in the 9872, and IIRC
the I/O processor of the 9845.

Although the 9825 and 9835 use the three-chip hybrid, it may be a
different version than the one that serves as the system CPU in the
non-bitslice version of the 9845.

Regarding my comments on the bit-slice processor:
> I have that. It's 3 PCBs with a little backplane on top to link them

Knowing how thorough you normally are with these things, I don't need
to make any special requests about your reverse-engineering effort.
But if at all possible, could you please dump the PROMs of that
processor assembly?

Best regards,
Eric