Sega Mega CD Capacitor replacement and repair

Mega-CD-1-reassembling

Replacing all the capacitors of the Sega Mega CD (v1). Installing new capacitors. reassembling and testing. surface mount capacitor leak. replacing with radial caps.

Mega CD Recap

I was recently sent an original Sega Mega CD by a customer. It was having an intermittent problem and displaying corrupted graphics on the side of the screen during boot and game play.

Typically for me it was being well behaved and showed no such problems. I went ahead and opened the unit to investigate more.

The Mega CD is a very sturdy bit of kit, well put together. When I got the metal shield off the main board, I could see some problems that might be causing the issues the customer mentioned. It looks like Sega choose to use a mix of surface mount (smd) and radial caps on the main CPU board. Just like NEC consoles of the time, the smd caps are leaking. Although its not as bad as I’m accustom to seeing in PC Engine DUO consoles, its nonetheless something that needs fixing asap.

It looks like the two worse affected caps are providing power stabilisation to the VRAM chips.

I removed the caps and cleaned the board with PCB cleaner. The solder from the original caps was very hard to remove because it was quite compromised from the electrolytic fluids. I needed to repeatedly flux the area used desoldering braid. Once all the old solder was removed I was relived to see the pads are still in good condition. I then applied new solder to the pads ready for new caps.

The original radial caps were still good, but we decided to replace all of them on both boards anyway. This is optional, but the smd caps must be replaced.

Testing

After reassembling everything I tested the Mega CD with and Mega Drive 1 and 2. Everything seems to be working as expected.

Returned to customer.

If you have a Mega CD that needs new capacitors, please get in touch here.

Neil – 8bitplus – 2018

13 Responses

  1. Bradley says:

    So I have a sega cd that powers on sometimes an sometimes it won’t but lights flicker when it does power on it won’t stay on what do u think it would b I’m waiting for my caps to come in to do a recap

  2. René de Kok says:

    Hello,

    I have a sega cd console that freezes at the bios screen.I tried recapping but to no avail.
    Do you know any other methode to fix this?

    With kind regards
    René.

    • Душан says:

      the big chip called “SEGA 315-5632” have damaged traces to the upper left corner near the one of leaked capacitors, I already fixed 2 units by patching those traces , they are very delicate, so be very careful!Clean very well than check the traces with multiplier, then proceed with soldering .
      In this area some pins are under the big IC so I can list you where they are going I already traced them so:

      from the big IC to the CPU
      pin 148 pin 64
      pin 149 pin 63
      pin 150 pin 62
      pin 151 pin 61
      pin 152 pin 60

      And this pin 156 goes to the IC Sanyo LC89515 or to the next IC on the left HM514270AJ8

      pin 156 pin 72 (sanyo) or pin 16 (HM)

      good luck !

  3. Adam says:

    Hi! I recapped my model 1 sege cd but now when the rf shielding is over the main motherboard, it shorts out and doesn’t turn on when powered on. When the rf shielding is removed from the main motherboard in the sega cd, or when the metal heat-shield from under the sega genesis is removed, it works. I would not want to destroy any chips or anything if there is an electrical issue arching something. Any help would be appreciated, thanks!

  4. miguel teixeira says:

    hello .
    my sega cd no video and no power.
    The lights and drive motor will Flickr sometimes.
    problem?

  5. Nick says:

    Hello,

    I have a japanese mega-cd mark 1, it has a problem with f1 fuse so I changed it.
    Great, it powers up now… but sadly it gets freeze on the bios background image.

    CD Drive is not powered up at all, and access led stay off.

    I don’t know what to do.
    Do you think a recap will do ?
    Where can I find those caps ? Wich one to change ?

    I really want my very own megacd back to life !

    Thank you for any help
    Nick.

    • 8bitplus says:

      Hi there. Frozen bios screen usually means either a faulty drive controller, or a problem with the cpu, ram or bios lines. A recap is always needed on MK1s and may help, but the problem could me more than that. If you need help send me an email and we can talk further. Neil – 8bitplus

  6. Stephen says:

    Would this be something you could repair as I wouldn’t know where to start?

  7. Stephen says:

    Hi,

    I have a mega cd 1 and it powers up but doesn’t read discs. I believe it’s an issue with the cd lens. Is this fixable or will it need a new lens and is it still possible to even get these replacement parts?

    • 8bitplus says:

      I’m sure it’s fixable. You’ll have to open the console to find out if it has a sony or JVS laser unit. You will also need the capacitors changing on the processor board if it’s not been done yet

      • I have a Mega CD that when I turn it on it reads the music from the game CD, now if I open the tray and put the same game back in it no longer identifies the music tracks. I couldn’t make it run games, only music disc. What can it be?

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