Shortasswattsy

Hi all, Would welcome some help if I'm posting in the right place. I purchased a vectrex from eBay with no picture but had sound. I'm not really tech savvy but tested the voltages across the on/off switch and realised one line had no continuity, so I used some circuit cleaner to clean the switch and now I have a picture when I turn it on with sound. It can take several attempts of turning on and off before I get that humming sound and a picture appears, I presume it needs to warm up? If I do get a picture it rarely stys on and flashes off with what looks like a streak of lightning across the screen. If it does stay on it gets to the player select screen and then flashes and resets once I hit a controller button. I have some experience with soldering and recapping in game gears and other consoles but no experience on such a dated system. Any help, advice or a point in the right direction would be greatly appreciated as I havnt been able to come across this specific problem in my research. Thanks all! VID_20210306_123227.mp4 VID_20210306_124041.mp4 VID_20210306_124449.mp4