Administrators Arcade King Posted September 30, 2011 Administrators Share Posted September 30, 2011 Symptoms : Dead Fix: PSU/AMP board has copped some corrosion damage due to a pair of leaking 100uf 6.3 v caps at C25 and C25. Here a pic of the effected areas, L1 was also damage but I managed to save it. Corrosion is a prick to work on and a lot of the times what looks minor can turn out to be quiet bad. Replaced C24(100uf 6.3v), C25 (100uf 6.3v), C27(100uf 10v) and C26(100uf 16v) all with 100uf 25v. C24 and C25 both leaked and caused track damage. Replaced UPC2405 with new 7805 5v 1 amp regulator and fixed damaged tracks. Not very good pics. PSU uses a PNP Darlington Transistor (2SB963) to switch on the power supply when the Megadrive is switched on. So you can work on the PSU on the bench you need to short the Emitter and Collector to power it up without the Megadrive. I simply removed the Transistor all together and shorted the pads. Once powered on I could see no current was flowing to the input of the regulator, I noticed power was rising VERY slowly at the TR4 transistor. There was a broken track from the positive side of cap C27 to the input of the regulator. When powered on the voltage would drop right down to .8 volts :rolleyes Problem turned out to be another bad track from the negative side of the 10v DC plug to ground. A simple jump and she fired right up with a nice strong 5V . :) Being a Jap Mega CD this is the screen you get when hooking up to a pal console. I went looking for a PAL bios to program but found this instead and sounded like its worth a shot. http://www.assemblergames.com/forums/showthread.php?t=27562 Anybody else tried this ? anyhoo I've burt the eu_mcd1_921027_regionfree_byteswap.bin and... :D Don't have any games so tried one of my daughters Audio CDs and it worked ok :D Just burnt myself a copy of Sonic CD so off to try a game, I'll then try a USA game to see if the region free bios does its job. Link to comment Share on other sites More sharing options...
OzTron Posted September 30, 2011 Share Posted September 30, 2011 Do you have another CD1 ?? Been after one for ages, even a dead one will do :D Link to comment Share on other sites More sharing options...
Krumm Posted September 30, 2011 Share Posted September 30, 2011 Nice work and good writeup, should be a great little machine for you. Do you have another CD1 ?? Been after one for ages, even a dead one will do :D They look alot better then the MegaCD2 dont they. I think its a brilliant looking machine and just needs a 32x whacked on top for the best tower of power gaming machine, well tallest anywho :) Link to comment Share on other sites More sharing options...
OzTron Posted September 30, 2011 Share Posted September 30, 2011 They look alot better then the MegaCD2 dont they. I think its a brilliant looking machine and just needs a 32x whacked on top for the best tower of power gaming machine, well tallest anywho :) Yes, dead sexy the CD1 was ;) I had a Sega CD years ago, man I wish I still had one :cry I'd even swap my PC Engine 'Super Grafx' for one Link to comment Share on other sites More sharing options...
Hollo Posted September 30, 2011 Share Posted September 30, 2011 Holy crap, and here I was thinking it was only a fuse! Looks like you might have saved it in the knick of time AK. Very cool you have switched the Bios as well. :cool: Link to comment Share on other sites More sharing options...
Frank_fjs Posted September 30, 2011 Share Posted September 30, 2011 Awesome! :D Thanks for taking the time to post this repair log, I was keen to find out what the problem was when you bought it and am glad you managed to repair it. Funny about the region screen, I have a Mega CD II which boots up just fine when docked to a PAL Mega Drive II console. Link to comment Share on other sites More sharing options...
Pash Posted September 30, 2011 Share Posted September 30, 2011 Thanks for taking the time to explain what you did to repair the mega cd Travis. I've got a feeling the one I've got may have the same problem, will have to open it up oneday and take a look. Link to comment Share on other sites More sharing options...
MangledLeg Posted September 30, 2011 Share Posted September 30, 2011 AK, great thread and writeup. Nice job on the BIOS too! @Frank: Yeah, you have some crazy Mega CD 2 that's not fussy about region controls ;) My Mega CD 2 is just as picky as AK's original machine, but a few switches on the SMD fixes all the region issues :) Link to comment Share on other sites More sharing options...
Frank_fjs Posted September 30, 2011 Share Posted September 30, 2011 @ ML, I don't think my MCD2 is special, I think it's the MD2 console. I got it from Thailand, and it is PAL and came with a 240V SEGA power supply, but maybe it has an Asian region setting? It plays PAL games just fine though. Link to comment Share on other sites More sharing options...
Administrators Arcade King Posted October 1, 2011 Author Administrators Share Posted October 1, 2011 Was going to do a follow up last night but ran head on into a brick wall with this thing :realmad: Went to play Sonic CD but the thing kept on opening and closing opening and closing. After an hour of scratching my head I found the tray's motor was spinning but the rubber band wasn't gripping so when the door closed it wasn't brining the CD spindle up to the CD and locking in. Couldn't find anything around the house that was a small enough replacement. I try to avoid using normal rubber bands because of their stretchyness. Solution. $2 hair bands from Crazy Clark's :lol They are thinner so I wrapped 3 around the pullys. Old Rubber band New and exciting solution. Results speak for themselves :) Now to try a game from another region and see if that region free bios works. Link to comment Share on other sites More sharing options...
Frank_fjs Posted October 1, 2011 Share Posted October 1, 2011 Haha nicely done, MacGyver would be proud. :) Link to comment Share on other sites More sharing options...
Administrators Arcade King Posted October 1, 2011 Author Administrators Share Posted October 1, 2011 Just tried snatcher CD USA and it worked :D all I need now is the 50/60 htz mod Link to comment Share on other sites More sharing options...
narf_ Posted October 1, 2011 Share Posted October 1, 2011 Very nice. Just got my self a hori fighting stick for the md i can see my self buying one in the future Link to comment Share on other sites More sharing options...
Hollo Posted October 1, 2011 Share Posted October 1, 2011 The poor thing must have breathed its last breathe when I first put it on... Great to now see a full resuscitation!! That's the reason I love getting stuff back to you guys - I know it'll get looked after, and it'll be in good hands if something does go wrong. That is really weird about that door opening and closing though. There was nothing to indicate there were issues like at all when I was using it. Man, I hope you get that broken NeoGeo running as well Trav! Although the issues on that (in my obviously way out opinion) looked pretty bad. Link to comment Share on other sites More sharing options...
Administrators Arcade King Posted October 1, 2011 Author Administrators Share Posted October 1, 2011 Yeah the tray worked first time for me to but clapped out. What was the issue with the other NeoCD? Dead? Link to comment Share on other sites More sharing options...
Hollo Posted October 1, 2011 Share Posted October 1, 2011 The non-working NeoNeo wasn't getting anything displayed on screen at all, and the drive made a horrid noise at least one of the times I tried to power it on. It doesn't look like it was mistreated, but I reckon it'd have to be a few issues that are pretty serious. The only reason I say 'serious' though is because it was like that when I got it. The MCD was working and then nothing at all, so at least I knew the CD drive was fine. Really hope you can get that NGCD working as well though AK. Would be cool to get two classic machines back from the dead and in Aussie! Link to comment Share on other sites More sharing options...
Administrators Arcade King Posted October 3, 2011 Author Administrators Share Posted October 3, 2011 Yeah once I get a 240v PSU or step down I'll have a look at it. :) Link to comment Share on other sites More sharing options...
Dr.Wily Posted October 20, 2016 Share Posted October 20, 2016 Bump this old thread ! I have the very first shot of a japanese Mega-CD 1. But one day without any reason it stop working. After long search, I did not find where is the failure. When I powering up the Genesis I have a blank screen, however the tray start to close (when it's open). No BIOS screen, no sound. - All fuses are OK - power\sound board works (I tested it on another MCD) - the BIOS works to. The issue may come from the interface board between Genesis and Mega-CD. It use a cable plug directly on a crystal oscillator on the MCD motherboard. But I can't test the motherboard on another MCD because interface board for this model is specific. I took some pics for understanding : The motherboard parts side The motherboard solder side MB Memory chips crystal oscillator sub board sub board connector interface board part side interface board solder side closer view of interface board's chips closer view of solder side + grey cable closer view of solder side + black cable It would be nice if someone can save this first release of this Mega-CD. Plus, his BIOS is not zoned. It works on both 50Hz and 60Hz Genesis. Link to comment Share on other sites More sharing options...
NEO-GEO Man Posted April 20, 2017 Share Posted April 20, 2017 Bump this old thread ! I have the very first shot of a japanese Mega-CD 1. But one day without any reason it stop working. After long search, I did not find where is the failure. When I powering up the Genesis I have a blank screen, however the tray start to close (when it's open). No BIOS screen, no sound. - All fuses are OK - power\sound board works (I tested it on another MCD) - the BIOS works to. The issue may come from the interface board between Genesis and Mega-CD. It use a cable plug directly on a crystal oscillator on the MCD motherboard. But I can't test the motherboard on another MCD because interface board for this model is specific. I took some pics for understanding : The motherboard parts side The motherboard solder side MB Memory chips crystal oscillator sub board sub board connector interface board part side interface board solder side closer view of interface board's chips closer view of solder side + grey cable closer view of solder side + black cable It would be nice if someone can save this first release of this Mega-CD. Plus, his BIOS is not zoned. It works on both 50Hz and 60Hz Genesis. The capacitors on the main board fail and cause this. Link to comment Share on other sites More sharing options...
NEO-GEO Man Posted April 20, 2017 Share Posted April 20, 2017 Symptoms : Dead Fix: PSU/AMP board has copped some corrosion damage due to a pair of leaking 100uf 6.3 v caps at C25 and C25. Here a pic of the effected areas, L1 was also damage but I managed to save it. [ATTACH=CONFIG]28506[/ATTACH] [ATTACH=CONFIG]28507[/ATTACH] [ATTACH=CONFIG]28508[/ATTACH] [ATTACH=CONFIG]28509[/ATTACH] Corrosion is a prick to work on and a lot of the times what looks minor can turn out to be quiet bad. Replaced C24(100uf 6.3v), C25 (100uf 6.3v), C27(100uf 10v) and C26(100uf 16v) all with 100uf 25v. C24 and C25 both leaked and caused track damage. Replaced UPC2405 with new 7805 5v 1 amp regulator and fixed damaged tracks. Not very good pics. [ATTACH=CONFIG]28511[/ATTACH] [ATTACH=CONFIG]28512[/ATTACH] [ATTACH=CONFIG]28513[/ATTACH] PSU uses a PNP Darlington Transistor (2SB963) to switch on the power supply when the Megadrive is switched on. So you can work on the PSU on the bench you need to short the Emitter and Collector to power it up without the Megadrive. I simply removed the Transistor all together and shorted the pads. Once powered on I could see no current was flowing to the input of the regulator, I noticed power was rising VERY slowly at the TR4 transistor. There was a broken track from the positive side of cap C27 to the input of the regulator. When powered on the voltage would drop right down to .8 volts :rolleyes Problem turned out to be another bad track from the negative side of the 10v DC plug to ground. A simple jump and she fired right up with a nice strong 5V . :) [ATTACH=CONFIG]28514[/ATTACH] Being a Jap Mega CD this is the screen you get when hooking up to a pal console. [ATTACH=CONFIG]28515[/ATTACH] I went looking for a PAL bios to program but found this instead and sounded like its worth a shot. http://www.assemblergames.com/forums/showthread.php?t=27562 Anybody else tried this ? anyhoo I've burt the eu_mcd1_921027_regionfree_byteswap.bin and... [ATTACH=CONFIG]28516[/ATTACH] :D Don't have any games so tried one of my daughters Audio CDs and it worked ok :D [ATTACH=CONFIG]28517[/ATTACH] Just burnt myself a copy of Sonic CD so off to try a game, I'll then try a USA game to see if the region free bios does its job. I have the region free BIOS in a few Mega CD systems, works well. The Mega CD i have is a very early model and has a socketted BIOS chip, which made it nice and easy for testing. I added a socket to my Mega CD 2 and threw one in there as well, which worked great. Link to comment Share on other sites More sharing options...
Administrators Arcade King Posted April 20, 2017 Author Administrators Share Posted April 20, 2017 Yeah been years since I've turned mine on but the Bios worked great. I downloaded a newer version awhile back, I'll have to update it however the one I installed ran very game I threw at it. Link to comment Share on other sites More sharing options...
NEO-GEO Man Posted April 20, 2017 Share Posted April 20, 2017 Yeah been years since I've turned mine on but the Bios worked great. I downloaded a newer version awhile back, I'll have to update it however the one I installed ran very game I threw at it. I only did all this last year so mine is probably a pretty late version. I dont play much Mega CD, there is a couple great games on it though. Link to comment Share on other sites More sharing options...
layo Posted February 21, 2020 Share Posted February 21, 2020 Hi, I don't know if it's the right place to explain my problem. If not perhaps I can create an new thread about my issue. I bought an Mega CD 1 japanese. I replaced all capacitors of the main board (twelve smd 10uf and two 100uf) and two 10uf and one 47uf located on the connection board (connection between MD and MCD). On the power board, I replaced all 100uf capacitors (three capacitors around heatsink and one on middle of the board). I have also clean all ribbons used to connect boards After all this work, I have a freeze during boot. I see background image (a white cloud because my bios is an japanese one) and the bios version number. But nothing else. No flashing leds. If I push on the reset button I get an black screen. I don't know what to check to solve my problem. I look at the main board but I didn't see broken trace. Link to comment Share on other sites More sharing options...
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