Video Banding Modification

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  Video Banding Modification: Many (most?) A4000s show some faint vertical
  bands on the display. There is a modification to prevent this, but, like
  anything else, it has advantages and disadvantages.

  Advantages
    Removes vertical bands from display.
    Simple modification.
    Relatively easy to disable.

  Disadvantages
    Interferes with operation of attached genlocks and deinterlacer
    boards like the Amber A2320 board (see Boards/A2320 'Amber' Reference).

  The modification involves connecting pin 15 of the video port connector
  through a 100 ohm, 1/4 watt resistor to ground. This can be done inside the
  A4000, but it's safer and more versatile if the modification is performed
  on the DB23-to-HDD15 adapter that was included with the A4000. That way the
  adapter can be unplugged from the machine if a genlock or Amber board is to
  be used.

  There are two grounds on the adapter PC board: shield ground and video
  ground (pins 16-20). Since all the other components on the board use the
  video ground, it seems reasonable to use it for this modification, rather
  than the more-easily-reached shield ground. The resistor fits nicely on the
  bottom of the adapter PC board, running from pin 15 to pin 18 of the
  connector's soldered pins.