Re: VECTOR: Aseroids tech question

Hey all.  My Asteroids has developed a horizontal line across the screen over which the objects "jump."  This also shows up on the test screen as "stretching" in the cross-hatch pattern.  I read on an Asteroids troubleshooting site that this may be related to a D/A converter.  Is this an easy fix?  Are the parts readily available?  Thanks in advance for any help.  
  It could be a bad DAC, or a bad counter driving it, or a bad op-amp following the DAC.  The DAC is by far the most expensive chip, and the hardest to get replacements for.  If you're soldering-savvy, you can isolate the problem by desoldering both DACs and swap them.  If this "invisible line" changes axes (from X to Y), then you've nailed it.  Swapping the op-amp chips works this way, too.