wrd@tekigm2.UUCP (Bill Dippert) (01/08/87)
The attached is a slightly modifed version of an article I sent out on the net some time ago. ------------------------------------------------------------------------------ Subject: XL/XE Monitor Output Jack Mods, Etc. Here is the solution for the lack of chroma in the 800XL that was published in the February ANTIC 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. Two questions: is the 200 ohm value correct (recently someone mentioned 220 ohms) and what is the proper value/connection point for the 1200XL which has a similar problem. In fact the 1200XL will not give color if connected to a separated video monitor in the same fashion as an 800XL. 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 Commodore 1702 monitor is nearly identical to that from 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.) Question: 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 -- the 800XL still has one pin not used (I think pin 4), what does this mean? Should this remaining pin be connected? If so, to what? Then on the 1200XL, I find that pin 5 is not connected to anything, but pin 4 is. Is pin 4 composite video on the 1200XL and if so, should I connect pin 5 to pin 4 or to something else (on the 1200XL) -- see 1200XL question above? 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