1958 RCA 14" Deluxe 14-PD-8057D

[Electronic M]

Dave makes a good point. Definitely make sure the aquadag is properly grounded to the chassis. Have you cleaned the area around and including the HV connector on the CRT? And if not are you familiar with the proper procedure to discharge the HV? If the answer to the first is no then discharge the HV and use windex and or rubbing alcohol to clean the bare glass between the edge of the aquadag and HV connector...Also disconnect the HV lead and clean the CRT HV connector, HV connector on the lead and a few inches of the lead it's self. That and grounding the dag should kill the arcing and reduce interference. If the HV connector has developed sharp edges that promote arcing/corona no matter how clean you make it then one option is to find a junk ~90's era CRT set and pirate the HV lead and suction cup HV connector out of it to use as a replacement for the HV lead and connector in your set.

If your set has AGC then you may want to adjust it for best synch stability. Your set was not designed to work better with bad caps, but if resistors drifted outside of rated tolerance (ie. went bad) in a way that compensated for the bad caps then installing good caps could throw that balance off...The solution is to look for out of tolerance resistors and replace them to restore vertical synch stability.