[comp.sys.atari.8bit] Chroma Output

wrd@tekigm2.UUCP (Bill Dippert) (11/29/86)

On the 1200XL, there is no connection made to pin 5 -- which should be the
composite chroma pin.  A similar situation exists on the 800XL which the
Chicagoland Atari Users Group has provided a solution.  Does anyone know if a
similar solutions exists for the 1200XL?  Presumably, somewhere on the main
board is a place where a 75/200 ohm resistor could be attached and run over to
pin 5.  I have wondered about the lack of anything going to pin 5 on my
1200XL's for sometime, but it was not until this week that I tried them out on
a monitor that will accept either composite or separated video.  The 1200XL
works fine on composite video, but when connecting it for separated video, you
get a black and white screen only, no color (chroma)!  I hesitate to merely
connect pin 4 to pin 5 as I believe that this would merely give one composite
video again.  I am using a C.Itoh CM1000 monitor for my testing, altho a
Commodore 1702 would probably show the same results.  Am using  a 5 pin DIN
connector with four RCA outlets plugs on it for connecting between the monitor
and the monitor jacks on the computers.  

Note to John Sangster:  the 200 ohm resistor works fine on the C.Itoh monitor,
apparently there is some difference between it and the way the Commodore 1702
is wired for separated video.  May try later to reduce the 200 ohm to 75 ohm,
but am not sure about the remainder of your suggestions.  

Has anyone access to schematics, etc. that they could look up and see if there
is a point analogous to the R67/R68 point on the 800XL -- on the 1200XL.  If
there is then the same solution could be installed.  Has anyone else out there
tried to use separated video on a color monitor with a 1200XL and if so, what
happened?  Did you in fact get b & w or color?  If color, how did you or where
did you get the chroma signal?

Thanks in advance,
--Bill Dippert--
tektronix!tekigm2!wrd