N64 powers on, screen briefly flickers, then nothing (no audio either)

Hi everyone. I’ve seen some people have success asking on here for help so thought I’d give it a try. To cut a very long story short, I’ve been trying to fix my (well my dads) N64 for the last 3 - 4 months and have so far had no success at all. I originally asked the N64 community over on reddit for help but had no luck there.

(If you’d like to read that for additional information, here’s the link: https://www.reddit.com/r/n64/comments/g4... )

So basically, when I turn the N64 on the red light comes on like normal. The TV (which is an LCD TV and it used to work on it for years) will briefly display some white static and bars/lines, for about a second, and then nothing. It just goes completely blank. There’s no audio either. So far I’ve:

• Cleaned literally everything I possible can with isopropyl alcohol (pins, contacts, plugs, connectors, cartridge slots, motherboard, everything!)
• Gotten a new AV cable and tested both the new and old one repeatedly
• Gotten a new expansion pack, also tested new and old one repeatedly
• Tried at least 5 different games
• Tested all the controller ports
• Tried running it through an old AV 3 input/1 output switch (it used to be run through it years ago and it worked fine), same results as when not using it.
• Tried 3 different TVs, each with varying ages (from old LCDs to modern a HDTV), didn’t work on HDTV but same result on both LCDs.
• Tested all the AV inputs on all the TVs I tried.

I’m seriously out of ideas now. If anyone has any ideas of how to fix it I would love to know.