5 
1 Power switch only works sometimes
I have a Sega Genesis (model 1) that has some issues with the power switch only turning on sometimes. It takes a few tries of turning it on and off again before the on light even comes on at all, but even then it doesn’t come on in the on position, only when I’m halfway through turning it off again. With enough back and forth it does come on properly, but it’s been taking progressively more time for it to do this (was fine when I pulled it out of storage ~5 months ago).
I’ve also noticed it’s got some other issues. The video kind of flashes brighter and darker on some scenes, mostly on menus. My other tv shows wavy lines that get worse the longer you play. Probably just the tv, but it’s annoying nonetheless.
I’m currently using an adapter I got at Goodwill, not meant for the system but it’s the right voltage, amps, and I’ve switched it so the polarity is right. I’ve had the entire system apart and made sure the outside part of the switch was lined up with the inside. Everything looked fine inside, nothing damaged. I’ve cleaned the adapter in port in case that was corroded. I’ve tried moving the wires around in case of there being a loose connection, same thing with the tip of the adapter. I’ve tried the adapter from my Sega CD (it seems to fit better). It could be something just inside the console because once I accidently touched the adapter tip while it was on and it rebooted, but I really don’t know. Any ideas?
Edit: Circuit board
crwdns2934109:0crwdne2934109:0
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I'm not exactly in the same boat but I can definitely concur with most of this. I ordered a Genesis fairly recently off eBay and it's in practically perfect condition except for 3 things of note:
1. Controller Port 1 has been replaced, this isn't an issue but it is worth noting for the sake that the console needed the port replaced to begin with
2. The Power Switch on mine also is finicky, if I don't turn it on properly the power LED will flash like it's trying to turn on, but immediately unsuccessful, some times I'll get it first try and others it will take several attempts before the console powers on properly.
3. The Reset button can also have a small error where it'll shut off any game running, but not reboot it, leaving it on a black screen. This is easily resolved by pressing it again obviously, but I don't think it's supposed to happen. (I theorize this could be connected to the power switch issue too but I don't have any real evidence to back that up)
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