baceman007 Posted June 19, 2018 Share Posted June 19, 2018 Hello everyone. I have a Sega Genesis Model 2 (more specifically an mk-1631). It was having problems loading known good games past the Sega Logo. These games load on two other Genesis systems that I have. So: 1. I tried to re-tension the slot. That didn't work, and the carts were still loose, so. 2. I soldered in a new cartridge slot, did a continuity test on all of the pins (it passed) so I tried again. Still, wouldn't pass the Sega screen. 3. I soldered in a new reset button at this point for good measure. The old one had a worn out rubber cap. That works correctly now. 4. So, I tested the capacitors, some were bad, so I re-capped the board. All new capacitors passed a capacitance test and the new connections passed a continuity test. So I tried again. Same issue. Won't pass the Sega screen on known good cartridges. My question is, what do I do now since, in theory, there isn't a problem with the cartridges, cartridge slot, or capacitors? Quote Link to comment Share on other sites More sharing options...
Taijigamer Posted June 19, 2018 Share Posted June 19, 2018 Do you have access to an O-scope? Maybe it's a problem with the 7805 regulator or a bad RAM chip. 1 Quote Link to comment Share on other sites More sharing options...
Jeremy Popp Posted June 19, 2018 Share Posted June 19, 2018 Hello everyone. I have a Sega Genesis Model 2 (more specifically an mk-1631). It was having problems loading known good games past the Sega Logo. These games load on two other Genesis systems that I have. So: 1. I tried to re-tension the slot. That didn't work, and the carts were still loose, so. 2. I soldered in a new cartridge slot, did a continuity test on all of the pins (it passed) so I tried again. Still, wouldn't pass the Sega screen. 3. I soldered in a new reset button at this point for good measure. The old one had a worn out rubber cap. That works correctly now. 4. So, I tested the capacitors, some were bad, so I re-capped the board. All new capacitors passed a capacitance test and the new connections passed a continuity test. So I tried again. Same issue. Won't pass the Sega screen on known good cartridges. My question is, what do I do now since, in theory, there isn't a problem with the cartridges, cartridge slot, or capacitors? Man, that's a lot of effort for a Genesis - for your sake, I hope you get it working. I've actually repaired 2 model 2 genesis consoles with this issue, and both times it was a bad trace on the motherboard that went to the cartridge slot. Sounds like you may have already looked that area over, but on both of mine I could see visual proof of some sort of corrosion on the board, and lo and behold one of the traces was bad. Good luck. Quote Link to comment Share on other sites More sharing options...
baceman007 Posted June 21, 2018 Author Share Posted June 21, 2018 Thanks for your reply guys. Very helpful.Taijigamer, I can get my hands on an O-Scope if need be. It's also on my Christmas list for my new electronics workbench! Yeah!Jeremy Popp, I took a much closer look at the board and although everything around the slot checks out ok, I found some goop and some black stuff around the SRAM (KM6264BL-10). Alcohol did not work, so I might try Brasso next unless you have any other suggestions. I am hoping the black parts are not breaks in the traces and can be cleaned up. Otherwise, I guess I'm soldering in some SRAM and trying to redo the traces in that area. Here is a pic. The damage I'm talking about is closest to the rest button. Quote Link to comment Share on other sites More sharing options...
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