Author Topic: Displaying 80-column Text on a Composite Monitor  (Read 1364 times)

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Offline Blacklord

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Displaying 80-column Text on a Composite Monitor
« on: December 09, 2007, 09:50 AM »
The C-128's 80-column RGB video output can be viewed on a low-cost monochrome
composite monitor that conforms to NTSC specifications.  By using a monochrome composite
monitor, you avoid purchasing an expensive RGB monitor to view 80-column text.
 (I'm assuming that a color composite monitor will work as well, though I havn't tried it D.K.)
     A special adapter cable must be constructed to connect the C-128's RGB output to the
monitor.  You will need the following components, all availabe at any electronics store:

   * A shielded video cable with an RCA-style plug (also known as a "phono" plug) at one
      one end.  A good quality audio patch cord will work equally well.

   * A 9-pin, D-style subminiature connector that will mate with the C-128's RGB video
               output plug.  (It will resemble the joystick port connectors on the C-128.)

   * A matching hood with two screws for the D connector.  (Screws normally come with
               the hood.)

   * A "pencil" soldering iron and 60-40 rosin core solder.

   * A small screwdriver that fits the hood screws.

     Strip enough insulation off the outside of the cable so that 3/8 inch of copper is visible.
Carefully unravel it and twist it into one conductor.  Then strip 1/4 inch of the center
insulation away so that the center conductor is visible.  Solder the "braid" (the braided
copper shield that surrounds the center conductor's insulation) to pin 1 or 2 (or both for that
matter) of the new D connector.  Then carefully solder the center conductor of the cable to
pin 7 of the connector.  Make sure no solder "bridges' exist between pins; only pin 1 (or 2,
or 1 and 2) and pin 7 should have anything connected to them.  Put the plastic cover over
the D connector, being careful not to short the two wires together or to move the wires so
that they accidentally touch other terminals.  Attach the D connector to its mate on the C-128
and use the mounting screws to secure it to the C-128 connector.
     Connect the other end of the cable (the end with the RCA/phono plug) to the round video in
connector on the back of your composite monitor.  After powering up the C-128 with the
80-column display active, adjust the brightness and contrast controls for the best image.
You will probably find that the 80-column output requires different setting for these controls
than does the VIC-II (40-column) output.