8 Jan
2017
8 Jan
'17
9:21 a.m.
I photographed both sides of the board and merged the
pictures together to
make a front/back composite. The trace for the cathodes of the 3 diodes
links together on the back of the board and doesn't go anywhere else. The
front trace from V302 cathode goes straight to R312. The anodes DO link with
the monitor driver board through the connection marked MON though.
OK, probably some kind of luminance signal. Was there ever a monochrome
version of this unit?
One of the reasons I'm asking these questions is
I'm trying to see if
there's another source of composite sync given that the MR9735 itself
doesn't do it, even though it should.
I doubt it.... Why would there be?
Is the MR9735 doing anything? Is it accessing memory, for example?
I still wonder if it has to be initialised (say to vewdata rather than teletext
mode) and if this is not occuring.
-tony