wrote in message
oups.com...
I've got a rare old vector arcade monitor from a "Warrior" arcade game
that came out in 1979. Everything works except that the picture is way
off center. To the point that about half of it is off-screen. I've
adjusted the horizontal and vertical controls as far as they go. So
I'm thinking I need to adjust the yoke. But I've never done that
before. I tried loosening the screw and I can rotate it which rotates
the picture. But I don't know how to move it to a different angle to
get the picture back in the middle. It's an old b&w monitor so I don't
have to worry about color convergience or anything like that. Can
someone give a novice a clue on how to go about this? Thanks!

John

John: There may be, as with old B&W TV sets a couple of usually black
cardboard looking circular pieces with tabs often mounted on and comprising
part of the back of the yoke. Those could be rotated (gosh how rusty I am on
this!) to magnetically centre the whole raster (picture)? Try that? I guess
the 'black things' were somehow magnetic and steered the electron beam?
There used to also be an 'Ion trap' that had to also adjusted; if it was way
off the picture would show on the screen at all! IIRC the trap was to steer
the electron beam/s back towards the screen to avoid ion burn? because the
tube gun was manufactured not exactly pointing at the screen. The ion trap
looked like a springy open metal clip around the tube neck and contained a
small magnet about half the size of postage stamp. Maybe that's missing? If
so try a smallish magnet to see if affects the problem.
But stand to be corrected on any of this by those more knowledgeable. Terry