Years ago I was given a broken LBP8-A1 -- the
formatter board had a dead
PAL on it. As I think I mentioned before, I removed the formatter board
and converted it into a CX-VDO printer (no intenral formatter, the
interface connector goes straight to the print engine) for my PERQ. I
still have the ROMs from the formatter board if you're crazy enough to
want to covnert an HP Laserjet (origianl version) into an LBP8-A1.
Tony, did you wrote something about that in a site before? Got the
adress on hand?
I am almost sure I mentioned it on this list in the last year. I would
guess serrchingthe archives for 'PERQ' would find it.
I am not sure what you want to know. I can talk you through taking the CX
engine apart, and what the 'DC contorller board' -- the print engine
cotnroller with a 7811 microcontroller and a gate array that controls the
laser intensity does. And how the various PSUs, laser scanner, etc work.
When I was doing this conversion, you seem I had the printer totally
apart. And I mean 'totally' I completely stripped down the optical parts
and had a pile of mirrors and cylindrical lenses at one point (yes, I did
get it all aligned again)
As regards the actual conversion, the important bit is trivial. A CX-VDO
has a DC37-S interface connector. It's a straight-through ribbon cable
from that to the first 32 pins of the 34 pin header on
the DC controller
board. The last 2 pins on that connector go to an earth tag on
I didn't bother with (and never found out the ocnnections of) the
mini-DIN connectoer for some kind of exeternal paper feed. The PERQ never
supported that, I don't have one, etc.
There's a 6 pin header on the DC controller board that's unused in the
LBP8. It carres the status LED signals (ready, paper out, etc). I
dismantled the original control panel from the LBP8 (and added a 7
segment display, switches, etc to the junk box), and used 5 of its LEDs
and the associated resistors on the origianl PCB. I made a new trim panel
for it (not the right layout for an CX-VDO, since I used the old PCB and
plastic housing from the LBP8, but that doesn't matter) and soldred a
length of ribbon cable to the PCB which ends in a sockt to fit said header.
Let me know what you're trying to do and I can probably help.