NEC PC-100 Color Video Pinout

NEC PC-100 is a personal computer based on 8086 (more pictures are here). Submodel PC-10030 is equipped with a color framebuffer board. Even with the color framebuffer board, CRT still connects to the connector on the motherboard. PC-10030 is usually used with a proprietary display PC-KD651, which supports pivoting (changing display orientation). This information is preliminary as we only figured out the protocols of video signals so far (we assume pivoting is just a switch though).

D-sub DE-9M connector on the motherboard:

 -------------
 \ 1 2 3 4 5 /
  \ 6 7 8 9 /
   \_______/
#Description
1Red
2Green
3Blue
4Hsync
5Vsync
6GND
7GND
8GND
9Pivot

Signal levels are VGA compatible, but the synchronization frequency is out of range of VGA signalling. Some displays support this freqency however.

Currently my PC-100 is working but the MS-DOS system disk is broken. If anybody can privide me with those diskettes, please send me an email.