Flashing K4600

[infariot25]

I just bought an old converted galaxian cabinet with a k4600 (no game board).  to my surprise the monitor actually worked, but it hadn't been turned on since being converted to a taito big event golf(i did get a trackball out of the deal). 

ANYWAY I turned it on and let it warm up for a while.  I had noticed earlier that the power wire that connects to the neck board sparked blue(spark at the neckboard connector), but the monitor continued to work correctly.
Eventually i had it working with advancemame.  Then one day i turned it on and it started flashing bright white.  This happened when there was no signal connected to it as well as with a signal.

When i connected a signal to it,  i could see the picture but the flashing was there.  When i say flashing i mean intense flashing.  Unplayable epilectic flashing.  The flashing pattern reminded me of a bright copy machine movement but much, much faster.

I jiggled the power wire connector on the neckboard while the monitor was on and I was shocked(scared the piss out of me)!! hahahha.  this may be the problem? bad power to neckboard?

Anyway I'm sure this needs a cap kit. but it was working before so does anyone have a clue what this problem is?

thanks in advance for your help!