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Thread: Various Hardware Problems With Mega Drive 1

  1. #16
    WCPO Agent CrossBow's Avatar
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    Okay...so I'm going to ask a few things?

    Are your Alien Soldier and MW4 carts repros?

    And the graphics glitches you show on Sonic 3 is incredibly similar to what I was getting on mine when the CPU wasn't making good contact through the socket I had installed. Try this for grins on Sonic 3...

    Pop in Sonic 2 or even Sonic 1 in first and play a few minutes. Then pop in Sonic 3 and see what it looks like?

    Also my Sonic 3 when it did this would still always lock up while playing...usually within about 10min in a game of it. Even though graphically it would appear fine on the main game screens. Only the title screen would give me the glitching.

  2. #17
    Wildside Expert Retropolis Zone's Avatar
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    I'm actually using a Mega EverDrive X3 for Alien Soldier and MW4. I initially thought the MED X3 was causing problems, but it runs flawlessly on another console I have. Sonic 3 got those graphical glitches on both original carts and the MED X3.

    I've also just tested Sonic 3 & Knuckles and it's not crashed after 30 minutes of playing.
    Last edited by Retropolis Zone; 05-01-2017 at 01:43 PM.

  3. #18
    WCPO Agent CrossBow's Avatar
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    Well..if you are sure the CPU seems okay, and it sounds like it is, then the other other thing I can think of is something flaky with one of the video ram chips? I believe they are the two near the VDP, SIPP package type chips.

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    A Light In The Building. Master of Shinobi
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    Quote Originally Posted by Retropolis Zone View Post
    So I think it's a pretty good bet that either the CPU itself or the VDP is the culprit for this stuff? I've used the RAM diagnostic tool and the RAM was all fine.
    Considering that resoldering the CPU changed the symptoms, I'd swap out the 68000 with a known good one for testing.

  5. #20
    Wildside Expert Retropolis Zone's Avatar
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    Quote Originally Posted by chessage View Post
    Considering that resoldering the CPU changed the symptoms, I'd swap out the 68000 with a known good one for testing.
    I'd try this if I had the tools/experience to desolder ICs safely. I've always found it difficult to fully get all solder out of the vias with solder wick and a desolder pump. If it's really gonna come down to replacing the CPU then I think my journey for fixing this particular console ends here - for now at least.

  6. #21
    Hedgehog-in-Training Hedgehog-in-Training L2000's Avatar
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    Sorry for thread hijack , I cannot post thread of my own yet but wanted to get some information from more knowledgeable members here for a problem I'm experiencing I have a V1 MD with language and region mod , the PAL colour fix mod and C-Sync pulled directly from CX C-Sync out , all worked well until last night during testing I started getting a noticeable buzzing sound through Din connector but not through stereo jack , after that the picture would randomly glitch to purple then back again to colour , strangely this only happens during bass heavy sounds .The audio buzz gets worse as the system warms up , there is no buzz or graphical glitches for about five minutes after system has been completely unplugged for a while then after that everything just goes to hell. I have checked the board for shorts , or anything that could be causing a grounding issue , could this problem be caused by failing caps and if so which ones would be the regular ones to check first . Any help with this would be appreciated.

  7. #22
    Hedgehog-in-Training Hedgehog-in-Training 3edd's Avatar
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    Have sort of an issue mentioned above. My Jap VA4 MD1 shows black screen only with any game inserted. Tried to reflow cart slot, CPU, SRAM and other ICs, checked traces between slot and ICs, all seems to be ok. Then i noticed that 68k CPU becomes very hot fast after powering on, no matter if a cartridge is inserted. Swapped m68k to a new one, same things there. Don`t know which IC may cause the problem now.

  8. #23
    Hedgehog-in-Training Hedgehog-in-TrainingSports Talker Madness Hero's Avatar
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    Any rusty or corroded traces on the board, did it take a long time to reflow any points uve soldered perhaps resulting in chip damage via heat? Also a multi meter with continuity beeper is a handy gadget to trouble shoot with especially if it reads ohms too because both continuity and resistance change when itroduce to heat for example u if u have a smal crack on a trace or solder point when your machine heats up your board could potentially expand the crack creating either resistance or a circuit gap. Another thing that might help is buy a cheap ir thermometer run your system for a minute and check the board for any areas of excessive heat. Wish i had a more definitive answer for you but trouble shooting tips is the best i can give you i hope it helps!
    "Keep your friends close but get your enemies toaster."

  9. #24
    Hedgehog-in-Training Hedgehog-in-Training 3edd's Avatar
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    Thanks for advice, man! Now I really think it`s a connection problem between cart slot and board logic somwhere altough I can`t see anything. Received a MegaCD Model 2 unit yesterday, put this "dead" board in it and it works! CDs run fine, thats good. Will try to check all slot traces again.

  10. #25
    Hedgehog-in-Training Hedgehog-in-Training 3edd's Avatar
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    Can anyone explain a bit how MegaCD works with console main unit? Does it use MegaDrive`s m68k and system RAM or it uses VDP only?

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