More Battlezone Problems

Hey All,

        While we're at it with Battlezone Problems, I've got a bizarre
one.

        My Z output is stuck on, so all of the retrace lines get drawn
(just as bright as all the "normal" lines) It's not a brightness/contrast
problem -- If I screw around with the brightness, all the vectors
(including the retrace vectors) change brightness uniformly.

        All deflection is OK. This problem happens on a tested good
19V2000 and a tested good G05, so I'm positive this is on the board
somewhere.

        I'm not sure what the Z output is supposed to look like (The G05
manual shows some bizarre waveform) but I socketed and replaced the
comparators which control ZBLANK and got no change. BUT, when I remove
the comparator on the X channel, things get a bit better (The picture
looks like it has the brightness turned up too much -- the retrace
lines are a lot dimmer than the normal lines -- but other wierd stuff
happens, most likely because that comparator is gone)

        Any ideas? Any ideas of what to look for on the Z output with a
scope/meter/whatever?

Thanks,

Joe
Received on Wed Jan 14 18:44:16 1998