Adapting digital RGBI monitor to accept analog RGB

Eric Christopherson echristopherson at
Tue Jun 14 11:02:38 CDT 2016

I am in possession of two Magnavox (North American Philips) CM8562
monitors. Out of the box they handle composite and digital RGBI (CGA)
input. What I'd like to do is get one to handle analog RGB (like arcade
boards, Amiga, Atari ST, and Apple IIGS put out). I wouldn't think this was
possible, but I seem to have a certain memory that I saw mention of doing
just that *somewhere* on the web a few years ago, even though I can't find
that mention now.

According to the rather unwieldy chart at
, the service manual and schematic for the Commodore-branded 1084 and
1084S-P is "also good for Magnavox ... CM8562". I assume this means the
monitors are basically the same underneath. Both of those Commodore
monitors support analog RGB. However, when I look at the service manuals
provided for those, they specifically state in several places that parts of
the manual referring to analog RGB do not apply to the CM8562.

Also, according to
, there are two chassis designations, which both confusingly include the
string "CM8562": CM8505/CM8562/CM8705/CM8762, 8CM505/8CM515/8CM542/8CM643
on the one hand; and 8CM542/CM8562/CM8762 on the other. The latter is noted
as only accepting digital RGBI.

Physically, both monitors I have have an 8-pin DIN input for the digital
RGBI, and a circular area with the legend "lin RGB" underneath. One one
monitor, that circular area is perforated; on the other one, it's just a
circle but with no indication that it can be easily knocked out. I have not
yet opened either one.

So... does anyone know if these monitors can in fact be made to accept
analog RGB? Or have a way I could tell after opening them up? And, of
course, I'd like instructions on just how to do it, if it is possible.

        Eric Christopherson

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