wrd@tekigm2.UUCP (Bill Dippert) (11/20/86)
There have been several requests recently on how to get chroma out on the 800XL and on what the pinouts are, so the following is a modified previous response that hopefully addresses the current concerns. ------------------------------------------------------------------------------ Subject: XL/XE Monitor Output Jack Mods, Etc. Has anyone tried the solution for the lack of chroma in the 800XL that was published in the February ANTIC (1985?) i/o board column? Essentially it says that the chroma output is at the emitter of Q5. You need to connect a 200 ohm resistor from the junction of R67 and R68 to pin 5 on the monitor connection. Credit for this goes to the Chicagoland Atari Users Group. R67 R68 _____ __.__ _____ ^^^^^ | ^^^^^ | | > > 200 ohm > > | | | pin 5 Note: resistors R67 and R68 actually are next to each other and not back to back as this diagram would indicate. I have intalled this on my 800XL and the picture I get on my C*******e 1702 monitor is nearly identical to that of my 130XE. (I would suggest to install this on the bottom side of the board. It is easier to get outside of the shield that way and also it is easier to solder.) The diagram for the 130XE shows -- pin 1 composite luminance pin 2 ground pin 3 audio output pin 4 composite video pin 5 composite chroma I find it hard to imagine that the 130XE requires five pins connected and that the 800XL and 1200XL only require four pins connected. And not the same four to boot!!! Also, the picture seems to be dimmer when I use the 800XL vs the 130XE. I suspect that maybe the 200 ohm resistor should be a different value? (Have deleted several similar questions, never have had any satisfactory answers.) SUBJECT: PIN CONFIGURATON: By the way the pin configuration (per the 130XE manual, as looking at the connector on the computer is: |_| 3 . . 1 5 . . 4 . 2 This pin numbering scheme is a German VDE standard and is common to all of the Atari 8 bit machines, however, not all utilize or have all five pins wired. --Bill-- tektronix!tekigm2!wrd