Ok so my 72 pin connector is not the greatest, so as I was trying to get a game to finally boot up while mostly getting gray screens (I have my 10NES chip disabled) it booted up with garbled graphics, powered off temporarily, then powered back on with the game now running just fine. Can anyone explain this symptom to me? Is there something going bad in my NES? I'm using a Sega Genesis Model 1 power supply with 9V, 1.2a

It almost seems to me like a short or something. I was using a Famicom to NES adapter, I've never seen it do this with a regular NES cart, at least not yet. Does anyone recognise why it does this sometimes? It only started doing this when I moved my NES to another room that has a high wattage oil heater that's on the same power strip (it's a heavy duty power strip from Home Depot designed for power tools).

Bad capacitors?

I've seen several original NES power supplies that were bad and caused problems exactly like a bad cartridge connector. An old Genesis power cord could have the same kind of problem.

A little over one year ago is when I first confirmed flakiness caused by a bad NES power supply. I hooked up my coworker with an NES flea market deal. I couldn't figure out why he had so much trouble. He just couldn't get it to boot. Every time I took it back home, it booted fine for me. Then I took it to my brother's apartment and had the horrible problems where it just wouldn't start reliably. Tried another power cord and it worked every time. The bad power cord works fine at my apartment, but not at my brother's apartment nor my coworker's house.

It reminded me of a computer I worked on over 10 years ago. The internal PSU was apparently bad. It worked fine at my apartment, but it just wouldn't boot whenever I brought it back to the owner's house. Then we discovered that it would boot fine at his house when we moved it to a different room. It blew my mind. The test was 100% repeatable without any inconsistency. In one room, the fan would only twitch every time. In another room, it would boot fine every time. New power supply unit fixed it right up. It was a very new house that had been built a year or two earlier.

Have you tried testing the system using an official NES adapter? I found for many systems some can be incredible picky when it comes to adapters.

Could just be a dirty / poor contact on the CIC chip. I have a Game Genie in very bad shape, and it randomly resets my game, just like you described. And bad contacts can also garble graphics.

EDIT, I see you disabled the chip. Points still valid on garbled graphics.

If the graphics are garbled, it's most likely related to the contacts. However, if you at any point are getting solid color screens that eventually switch to game screens, then you probably have failing capacitors.

Ok thanks for the responses. No I haven't tried the official AC adapter from Nintendo, only DC power adapters for the Genesis Model 1