Atari 1200XL ClearPic Modification

Another wonderful 1200XL modification by Bob Woolley of SLCC, Atari Classics Magazine.

                           Got a 1200XL with bad video? With a few simple changes under the
                          hood, you can get rid of that tearing, fuzzy screen and add separate
                          CHROMA operation.

                           Unlike the movies, the sequel to the CLRPIC modification is much
                          "better" than the original. If you were disappointed that the CLRPIC
                          mod did not allow for a COMPOSITE output, or felt intimidated by the
                          lengthy list of changes in the original upgrade, then you are at the right
                          place. This version only requires you to remove 10 components and
                          add 4 wires and 4 components! IT IS STILL A GOOD IDEA TO HAVE
                          SOME ELECTRONICS SOLDERING SKILLS. Also, these changes
                          were developed empirically, which means I just diddled with the values
                          until they worked. The output is very good - better than an 800XL and,
                          depending on your preference for overdriven characters, better than a
                          130XE or 800 in separate CHROMA or COMPOSITE video.

                           On with the changes. As in the original CLRPIC article, I will list the
                          existing component in the left column and what to put in it's place in
                          the right column. A "--" indicates that nothing is to be connected and
                          "wire" calls for a jumper, shorting out the part.

                          REMOVE:                  REPLACE WITH:

                          C115      10uf                wire
                          C60       100pf               --
                          R187      1meg                2.2K
                          L15       820uh               wire
                          R188      750                 680
                          CR19      1N4148              --
                          C119      3.9pf               --
                          C62       10pf                wire
                          R24       180                 47
                          R23       180                 47

                           Add a wire from R44 (either side) to pin 5 of J2.