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Need LaserWriter II-NTX connector pinouts and "fake out" advice


I recently bought a LaserWriter II-NTX logic board (Apple P/N 630-0158 with 8-out-of-12 SIMMs populated)
My crazy plan is to bring it up without the rest of the printer, so I can chat with the PostScript interpreter.
The LaserWriter II Repair Manual spends almost no time on the logic board.
(On the outside are "the usual connectors:" Serial, SCSI, LocalTalk, and the DIP switches)
On the inside, there is exactly one connector
(J18 - a grey 16x2 shrouded male header, in the photo indicated by my needle-nose pliers).
Every internal I/O signal goes to this connector plus power.
The $6,400 questions (roughly the original retail price of this printer) are
a) What are the pin-outs for this connector?
b) Will the board still respond to the serial port if it fails the self-test? (e.g. when the rest of the printer is like totally not there)
c) Anyone out there know how I can "fake it out" into believing that the rest of the printer is there and functioning?


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Well-known member
I can sort of answer B. With my IIg, I know that if it failed a self test, in my case the fuser blew, it sent an error to the Mac that said temperature error. That was using the built in Ethernet, which is really just ethertalk. An NTX with serial should act about the same.


An UPDATE: One our members kindly sent me the schematics and it shows all the signals that connect to J18.
He mentions kinda what I suspected, that if this logic board can't talk to the print controller, it reboots.
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