[Coco] Help with RGB cable

[Torsten Dittel]

Marcus Vinicius Garrett Chiado schrieb:

> Thank you very much, Rob. I recently bought a *real* 1084S (a D-II
> model) and will try to use my actual cable with it for it has
> composite sync already. As soon as I pick the monitor up, I will let
> you know.

Marcus,
the pinout on coco3.com is correct. I don't know this Apple monitor, but 
like the 1084S it seems to need R, G, B signals plus a signal called 
"Composite Sync". The CoCo3 already outputs R, G, B. For the missing 
"Composite Sync" there are two choices now: You mix it from H & V 
(horizontal and vertical sync) with the circuit described in an earlier 
posting. Or: you use a so called "Sync Stripper" to generate it from the 
CoCo's Composite *Video* out (another one-IC circuit). Disadvantage of 
both solutions: You need a 5V power e.g. from another port of the CoCo 
(joystick). Now the good news concerning at least the 1084S (no idea 
about the Apple): The Composite *Sync* input already seems to have a 
Sync Stripper circuit (which filters out the video information from the 
signal). That means with a special Y-cable (1084S: D-SUB9, CoCo3: Cinch 
and 9-pin header connector) you can use the 1084S in its RGB mode. Of 
course you could just use its Composite Video mode (with just one Cinch 
Coax video cable) but then the picture (and color!) quality is 
significantly worse. Any questions: feel free to ask.

Regards,
Torsten