Tempest pcb help

HI im new to the list. My name is Charles Tweedy, im a network manager for a
City in Va. Im a electronics tech as a hobby, and I collect video games. My
interest
is in vector related games. I own 2 extra Tempest boards I want to fix as
spares.
In my painful exploration of the pcb, im stumped and thought it wise to get
more
opinions from more skilled persons. each board is different in problem.

BOARD ONE: This one jitters very badly, even the colors jumped out of
convergence.
the game plays and sounds fine. I have tried replacing the pots and touching
up
the solder joints on the molex plugs. The aux board on both boards are fine
and
tested on a known good main pcb. Is this a chip problem? Dac maybe?

BOARD TWO: Well this one is kinda dead. Spot killer stays on in play mode.
In test mode I can get a Picture, without the line around the screen. I have
checked
the x and y outputs, they are around +/- 6 or 8 volts, but does not swing. In
thinking
there is no x or y deflection happening I replaced DE12 and 13 with no luck.
The
connector to the good aux is ok also. The cable is good also. Can a cap do
this?
I replaced DE11 also. Im really stumped on this one. Should be easy. Any chip
I could swap with the other board to get 1 working?

Thank you to all that can help. I appreciate your time.
Received on Tue Aug 24 12:03:42 1999