(I say that and, looking at my CGA card in graphics
mode, there are single-bit
errors twitching on and off -- RAM tests okay so I guess the ramdac has blown a
gasket somewhere)
RAMDAC? On a CGA card? Surely you jest...
More seriously, this could be a timing problem in one of the latches,
etc, between the RAM and the video output connector. I don't have the
schematic in front of me, but I can look it up if you're interested.
No, correct that. You have the card. You have a multimeter. Stop stealing
my time and trace the circuit yourself (well, that's what you told me to
do about writing programs).
capacitor in
parallel with the head significantly reduced it.
You wrote "fix" earlier... "reduce" makes more sense.
It reduces the amplitude of the glitch to such a level that it no longer
damages the tape. In that sense it fixes the problem (of damaged tapes
when the recorder is stopped in play mode).
-tony