chilicheesefried Posted January 10, 2015 Share Posted January 10, 2015 (edited) I was not paying attention and tried my NES power supply on this untested Genesis 1 model since they were both 9v. The output is 9V AC from the original NES power supply and the genesis takes 9v DC. The red light illiuminate with the NES power supply, however when I put a 9v DC power supply on the Genesis the power LED does not come on. I do have 9v DC on the multimeter where the red and white wires meet the mainboard. Thanks for any help. Edited January 10, 2015 by chilicheesefried Quote Link to comment Share on other sites More sharing options...
+xucaen Posted January 10, 2015 Share Posted January 10, 2015 You need to match the voltage and polarity on a power supply in order for it to work. If the polarity is opposite between the NES and genesis, you may have fried the genesis circuits. Here's an image of the Sega power supply. Notice the polarity is the marking like this: (-) ---C---- (+) 1 Quote Link to comment Share on other sites More sharing options...
chilicheesefried Posted January 10, 2015 Author Share Posted January 10, 2015 I checked the NES power supply and it doesn't have that information. Quote Link to comment Share on other sites More sharing options...
mickcris Posted January 11, 2015 Share Posted January 11, 2015 (edited) Since the NES power supply is AC it will not have that info as the polarity will cycle positive and negative. You probably blew the 7805 voltage regulator when you plugged in the wrong power supply. Edited January 11, 2015 by mickcris Quote Link to comment Share on other sites More sharing options...
chilicheesefried Posted January 11, 2015 Author Share Posted January 11, 2015 (edited) Thanks for the input. My confusion is that I do not have voltage going into these two regulators. Edited January 11, 2015 by chilicheesefried Quote Link to comment Share on other sites More sharing options...
mickcris Posted January 12, 2015 Share Posted January 12, 2015 there may be a filter cap in between the where the power comes in and the voltage regulator then. Trace the power to see where it stops. 1 Quote Link to comment Share on other sites More sharing options...
Rick Dangerous Posted January 12, 2015 Share Posted January 12, 2015 A local electronics repair shop should be able to fix that for you, definitely don't chuck your NES!! Good luck Quote Link to comment Share on other sites More sharing options...
Xot Posted January 14, 2015 Share Posted January 14, 2015 I would have sworn that the Genny PS worked on the NES, but not vice versa. I know I tried it Your decades ago without frying any consoles. Your mileage my vary, especially on now-20+ year old consoles. Quote Link to comment Share on other sites More sharing options...
+xucaen Posted January 14, 2015 Share Posted January 14, 2015 From what I've gathered on the internet, the Genesis power supply will work in the NES because the NES can somehow magically handle the reversed polarity. And from what I've gathered on the internet, using a NES power supply on a Genesis will fry the Genesis. If u plugged a NES power supply into your Genesis then your Genesis is fried. Quote Link to comment Share on other sites More sharing options...
chilicheesefried Posted January 14, 2015 Author Share Posted January 14, 2015 From what I've gathered on the internet, the Genesis power supply will work in the NES because the NES can somehow magically handle the reversed polarity. And from what I've gathered on the internet, using a NES power supply on a Genesis will fry the Genesis. If u plugged a NES power supply into your Genesis then your Genesis is fried. This is what I have gathered as well, but the question is what particular component on the board "fried?" If the regulators I would think they would at least have some input voltage, but they do not. There must be something before the regulator and after the input source. This is what I will be looking for next time I take it apart. 1 Quote Link to comment Share on other sites More sharing options...
+xucaen Posted January 14, 2015 Share Posted January 14, 2015 This is what I have gathered as well, but the question is what particular component on the board "fried?" If the regulators I would think they would at least have some input voltage, but they do not. There must be something before the regulator and after the input source. This is what I will be looking for next time I take it apart. My humblest apologies, I misunderstood. Quote Link to comment Share on other sites More sharing options...
chilicheesefried Posted January 14, 2015 Author Share Posted January 14, 2015 No prob....we are on the same page. Quote Link to comment Share on other sites More sharing options...
mickcris Posted January 14, 2015 Share Posted January 14, 2015 From what I've gathered on the internet, the Genesis power supply will work in the NES because the NES can somehow magically handle the reversed polarity. And from what I've gathered on the internet, using a NES power supply on a Genesis will fry the Genesis. If u plugged a NES power supply into your Genesis then your Genesis is fried. The NES has a bridge rectifier directly after the AC input that converts it to DC. Since the Genesis power supply is already DC, the output is the same as it would have been if the NES AC adapter was used. Quote Link to comment Share on other sites More sharing options...
chilicheesefried Posted March 14, 2015 Author Share Posted March 14, 2015 (edited) Replaced the voltage regulators using a 9v 1.2a power supply (positive on center pen) and it is still dead... Total bummer... Edited March 14, 2015 by chilicheesefried Quote Link to comment Share on other sites More sharing options...
chilicheesefried Posted April 19, 2017 Author Share Posted April 19, 2017 (edited) I decided to break this out again. It appears pins 4 (ground) and 13 (Vcc) on the CXA1034P (power amplifier) are shorted. Cheapest source for the power amplifier is $7, which is twice what I paid for the console itself. Anyone know a cheaper place to get a power amp IC? Edited April 19, 2017 by chilicheesefried Quote Link to comment Share on other sites More sharing options...
chilicheesefried Posted April 20, 2017 Author Share Posted April 20, 2017 (edited) IT LIVES!! Apparently polarity of the power supplies changed over the years. Negative is center on this older model. Edited April 20, 2017 by chilicheesefried Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted April 20, 2017 Share Posted April 20, 2017 Yes...the original SMS and Genesis HDG units have center tip negative on the polarity. They changed it starting with the model 2 I believe. Quote Link to comment Share on other sites More sharing options...
atarilovesyou Posted April 21, 2017 Share Posted April 21, 2017 Thanks for bringing this up, as I had the same thing happen about two or so years ago with my Model 1 Genesis. I completely accidentally plugged my NES power supply into it. I got a weird looking screen, investigated, found out my error, and shook my head in dismay. I ended up getting a new motherboard from a member here, so I have one that works but I kept the old board in hopes that it may be resurrected. The thing is that it's not fried as such, it will usually load up a game. It's just that after a period of time, the game will freeze....randomly, at will. Or it will glitch. In any case, it was a shame. The back of the board looked like the solder joints were dull...not shiny like my replacement. So I tried to reflow the cart port solder, but that didn't really work or do anything. I sanded down the slot pins very gently, just to see if that was an issue...in retrospect, I probably shouldn't have gone that far. Probably didn't help. I'm still at a loss for what happened to it. I kept the exterior because it's in really great shape, but I lucked out finding a "high res graphics" model board as they're kinda getting to be a bit pricey these days. I still have to clean out the cart port properly but if you have any suggestions (or anybody here) as to what may be wrong with my old board, please chime in. It's now missing it's original LED leads (donated to the replacement board which was missing it), but if someone can suggest what could be replaced to get it more stable, that'd be cool. To be clear, it wasn't powered on very long with the NES power supply....few seconds at best. It was just one of those mistakes. Quote Link to comment Share on other sites More sharing options...
atarilovesyou Posted April 21, 2017 Share Posted April 21, 2017 Yes...the original SMS and Genesis HDG units have center tip negative on the polarity. They changed it starting with the model 2 I believe. ...wait: so using a model 2 Genesis power supply on a model 1 Genesis will reverse polarity? Won't that fry a board too? Wow...if so, I've dodged a bullet because I thought you could use either supply for either system. Can somebody confirm? Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted April 21, 2017 Share Posted April 21, 2017 The Genesis model 2 adapter won't even physically fit into a model 1. The plug on the model 2 has smaller diameter and the center opening on the power supply plug is too small as well. Likely done on purpose just because of the polarity change. Quote Link to comment Share on other sites More sharing options...
atarilovesyou Posted April 22, 2017 Share Posted April 22, 2017 I'm kinda confused...how does finding out the polarity is switched on different power supplies help save a system that had DC voltage pulse through it? Doesn't make sense. Maybe the OP can explain a bit more. Quote Link to comment Share on other sites More sharing options...
chilicheesefried Posted April 22, 2017 Author Share Posted April 22, 2017 (edited) These systems run off DC (Direct Current). It is likely the system survived due to a diode blocking current when it was applied with reversed polarity. This is a very common safety feature in complex PCBs (printed circuit board). DC voltage does not "pulse" as you said, it would best be said as "flowing" and is measured in amps. I think you are trying to compare your board to my board to understand what is wrong with your board. If this is the case, I don't think the problems are comparable. Start another thread and we can try to work out what is wrong with your board in there. Be glad to try and help there. Edited April 22, 2017 by chilicheesefried Quote Link to comment Share on other sites More sharing options...
atarilovesyou Posted April 24, 2017 Share Posted April 24, 2017 My thread was started a couple years back when this happened. There wasn't much in the way of info. Since our boards are the same, and we did the same thing (NES supply into the Genesis) I was hoping that perhaps the damage would also be similar...in which case I was hoping to glean some of what you did to get your board working again. But of course, you never know what's going to fry out when something like this happens. What confused me was when you mentioned the polarity of the power supply, and that it 'lived again' because of it...or was it your power amp that blew, you replaced it, and all was good after that? Just hoping to get lucky with my board, but since I'm really not a tech I can't troubleshoot the thing...safely, that is. There was a technical thing on youtube I found where a tech was troubleshooting the more common things that go wrong with the system, but that seemed more angled to shops that were renting the systems back in the day. Quote Link to comment Share on other sites More sharing options...
chilicheesefried Posted April 25, 2017 Author Share Posted April 25, 2017 (edited) was it your power amp that blew, you replaced it, and all was good after that? Link me to your thread, I would like to read. 7805 is a voltage regulator which reduces voltage. I did not bench test the 7805 removed, I simply replaced and tossed the old one. They are inexpensive. All was not well after that...had polarity wrong on the power supply that I made for the console after the NES/AC 9v did not work. As mentioned, Sega switched polarity. The one in the image above is wrong for our earlier models because they show reversed polarity...be careful what you read/believe on the internet. Edited April 25, 2017 by chilicheesefried Quote Link to comment Share on other sites More sharing options...
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