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NEC PC-8801A Manual/Printer Port

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kalinchuk

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Hello,

I'm not sure if this is the right category for this but has anyone come across an English manual for the NEC PC-8801A computer? I would like more information about the printer port as I'm not able to print anything from it. When I connect it to a printer, pin 13 (selected/online) is always LOW and it seems to be driven by the NEC computer as that pin switches from LOW to HIGH when the printer "online" button is toggled (without it being connected to the computer). With the pin being LOW, it does not print anything since it thinks the printer is offline but why the LOW signal from the NEC!?

Anyway, enough with the rant. I would appreciate it if anyone has the English version of the manual for this computer.

Thanks!
Artem
 
I've never seen an English manual, but I am happy to help with getting the information you need out of the Japanese manuals and books.

Seems to me what you really need for this is the circuit diagram (回路図) for the PC-8801, which I've not been able to find. (But they may have been published in I/O magazine at some point; if you can figure out which issue, it's probably on archive.org; if not I can probably get a paper copy and scan it.)

Possibly the PC-8001 (see page 4, "ROM & I/O" will be close enough), though that doesn't include pin numbers, so I'm just doing my best comparing the names with the Centronics spec.

I don't see any obvious select input, though it may be "P/S" ("Printer/Select"?), which is pulled up to +5V, on this model. I wonder if they pull it to ground on the PC-8801; you could trace it with a multimeter to check it out. But it looks unused, in which case you can probably just ignore it, unless your printer is accepting that as an external "select" signal that's disabling it.
 
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@zu2 Nice find! Those Shuwa System Trading Co. "kaiseki" manuals are invariably awesome, though it had never occurred to me that a manual reverse-engineering BASIC would also include a schematic. BTW, the main item page for that book is PC‐ 8801 N 88‐ BASIC解析マニュアル 川村清.

I found it rather odd that the schematic appears to show the printer port as having only a BUSY line and the data lines, but looking at the connector diagram, that does indeed seem to be the case, and line 13 is not "selected/online" but not to be used. (Though presumably connected to ground, rather than N.C. as the diagram says. That's easily verified with a continuity tester.) So that solves the OP's problem, I guess.
 
After some debugging, it turns out that my issue was actually with pins 10 & 11 (ack and busy). I had them reversed. I had to create my own cable for the printer as it's almost impossible to find a 36 pin to 14 pin CT cable. Thanks for the help.
 
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