Tech: G05 802 XY monitor - darn lines and no contrast

[OTTOgd]

The monitor on my Asteroids was actually fine and playable aside from occasional jitters/jaggies before I installed a cap kit. At first power on it seemed to blaze too brightly with 'spider legs' but then I turned it off and back on and now it is dim with 'spider legs' with brightness set to full and the contrast pot doesn't seem to do anything? Maybe just a new contrast pot?

Any other ideas?

Thanks for looking.

[qrz]

the few i've seen were plauged with cold solder joints .
inspect and resolder anything questionable .
test - still no go ,
then check the following :
r518 470k
r515 3.3k
r513 220
q503,504  MPSU03
q502 2N3906
also verify the 90 volt souce  P500 pin 1

schematic here: http://technical-department.servegame.com/monitor_schematic_diagrams/electrohome/G05-802.pdf

[OTTOgd]

Thanks a lot for the great info, qrz! I'll post an update when I'm up and running.