Originally Posted by
Niku-Sama
so while you were away I got a SNES with a similar problem, it was in pretty bad shape on the outside but the innards seemd ok, no corrosion or damage of any sort to the PCB.
some logos, megaman X did the Capcom logo and then nothing, other games did similar if they had a logo of that sort. gradius III had a bar pattern but it usually does when it boots any way.
I searched and searched, if it were the PPU I would imagine the problem would be consistent, any thing graphical wouldn't work or would all be garbled but at least go into the game.
after some searching I found some one with a similar problem as ours and said the 7805 wasn't quite putting out enough for the board. so I tried replacing the one on mine and it flickered on and immediately right back off like it had blown the fuse except theres still continuity across the fuse, its still good. I jumped it to be sure and still no life.
so it seems to me that mine was a combination, the 7805 was putting out barely enough voltage but I didn't test for amps. I have a feeling that my known good 7805 was more than some of the components, most likely caps, could handle any more due to age and that's why it seems like the fuse has popped.
shortly after that I had a similar thing happen with a master system. replaced a VRM and it popped a cap, replaced the cap and the system booted. come to find out though that master system has more problems still but that's for another thread