18 Jan
2016
18 Jan
'16
1:07 p.m.
indeed this machine has a 98204B video board (intended
to work with a 35721 monitor,
which I don't have). I have not yet found the specs for its composite signal.
It is normal composite video voltage levels with faster-than-normal horizontal scan rate.
If you have a frequency counter (or something that can be used as one, then put the
98204B
text board in the topmost position of the 9817, leaving out the graphics board (the
machine
will run without it) and take the top casing off the 9817. Take care to avoid the live
mains and
worse on the PSU board, power it up, and check the HS and VS pins of the 6845 (the only 40
pin IC on the board)
Most, if not all, cheap composite video converters assume US or European TV rates and are
not going to lock to this thing. If anybody knows of an interface that will work, I'd
be
interested to know about it too (I have a 9817 with the 98204B card, fortunately I do
have the right montor for it).
-tony