PCjr monitor schematic found at Computer Reset

Hardware questions and modifications

PCjr monitor schematic found at Computer Reset

Postby DoctorOctal » Fri Nov 06, 2020 7:13 am

Recently someone found manila folders containing PCjr technical notes at Computer Reset. I’ll scan and upload the full contents in time, but for now I want to post something of particular interest: the schematic diagram for the PCjr monitor.

The monitor schematic in the PCjr technical reference manual is for the IBM 5153 Color Display, and this is the first time I’ve seen a copy of the schematic for the 4863.

Unfortunately the image quality is not good. It’s an 11" x 17" photocopy of a photocopy, and somewhere along the line there was a reduction in size from the original. The diagram lost details, and many of the hand-written labels are unreadable.

I made several scans on an 8.5" x 11" scanning bed and stitched them together in Photoshop. I’ve attached a 300 DPI, highly-compressed JPEG version just to get it posted relatively quickly but will upload a better version later. The 600 DPI PNG version isn’t going to make it any more readable, however. I left several pixels of margin on the perimeter, so what you see is complete. I didn’t cut off the handwritten copyright notice at the top, for example.

Maybe a better copy will turn up at CR, but I’m not holding my breath: there was another, enlarged copy of the schematic in the same folder, and it was simply a photocopy enlargement of the other one. Someone went to the trouble to make partial enlargements and tape them together into one large sheet, and I presume he would have started from a better example if he had known of one.

I’ve also attached scans of the two sides of the back, where someone made troubleshooting notes.

Does anyone know of another copy of this schematic?
Back right page.jpeg
(972.57 KiB) Not downloaded yet
Back left page.jpeg
(942.52 KiB) Not downloaded yet
IBM PCjr Monitor 4863 schematic 300 DPI.jpeg
(964.28 KiB) Not downloaded yet
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Re: PCjr monitor schematic found at Computer Reset

Postby Trixter » Fri Nov 06, 2020 1:52 pm

Thanks very much for attempting to rescue this!
You're all insane and trying to steal my magic bag!
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