XREF on Tempest?

G'day,

Replaced all four opamps (TL082's) with no change. The bottom half of
the Tempest picture still isn't being displayed? As I've said before,
I've plugged this board set into another Tempest to verify that this is
not a monitor problem.

Can anyone explain what XREF and YREF does in the vector generator
section of the non-Star Wars Atari color XY's? If these serve as
references in the vector generator section of the PCB, could it be
possible that these are voltages at a fixed value that XOUT and YOUT use
as a baseline? If so, maybe my problem is that XREF is too high or too
low and why everything on the bottom half of the screen is scrunched
into a couple line? I should say that I can see "details" in those
couple lines showing me playing games....but, oh, is it hard to see the
bad guys coming up that half of the tube! 8^) 8^) 8^)

I sure wish I had an oscilliscope to debug this....

                Steven S Ozdemir
                sso@dsc.com
Received on Mon Dec 1 11:58:15 1997