Sega Mega CD 2 PAL no disc spinning.

umrotzer · Feb 28, 2021

Hey guys,

hopefully someone here has an idea.

1. I checked many repair videos and also threads I could find, but non of that fixed it.

OK here is what ive already done.

- replaced power fuse with a new 1,5 A fuse
- replaced the laser unit with a new KSS-210 A laser
- tweaked all potis to test (laser poti between 650 - 850 ohm)
- rearrgend the disc holder so it is close enough over the laser but can still spin free
- cleaned the board
- checked all disc drive to motherboard cables for continuity (all good)
- tested the spinning motor with 5v and also good and spins up.
- all caps look clean and good and should also have nothing to do with the disc spinning / reading

So i know the Sega CD only spins up if it see the disc in initial scan, so their must/should be the fault. But I have no more ideas and I hope someone has more ideas.

Edit//
The only thing that comes in my mind is the power supply. I know many use a 9v 1,2 a and higher ps, but if I look at my Sega CD (backside) it shows 10v 1,2 a and I only have have hooked up a 9v 4a power supply. So this 1v difference could be the issue?

I know that if I use a 9v power supply on my mega drive 2 it wont boot up, so could this be the reason or is the 1v difference in the Sega CD unnecessary?

umrotzer · Mar 7, 2021

Update//

Got my orginale power supply but same problem. Doesn't read disc of tries to spin up.

So anyone any suggestions?

JaapDaniels · Mar 7, 2021

umrotzer said:
Update//

Got my orginale power supply but same problem. Doesn't read disc of tries to spin up.

So anyone any suggestions?

is the sega megadrive underneath same region? Sega did a double region lock.
check the direct current diode bridge in the console, could be it missing one diode, wich will give a somesort of dc, just half the juice.
there should be a trigger to detect lid or tray is closed, it could be just a push switch.
is this detected like it should?

umrotzer · Mar 7, 2021

JaapDaniels said:
is the sega megadrive underneath same region? Sega did a double region lock.
check the direct current diode bridge in the console, could be it missing one diode, wich will give a somesort of dc, just half the juice.
there should be a trigger to detect lid or tray is closed, it could be just a push switch.
is this detected like it should?

It's a PAL system and the BIOS should be untouched, where is (Or should be) the bridge location u are talking about.

The trigger is OK if i press it together without top cover on it acts like it should. To tested it I have put the laser all way to the end and if I close the trigger by hand the laser moves all the way in, tries to focus (Lens up/down) but no spinning. The same process also happens with cover on I can hear laser moving aso, so the switch should be good.

JaapDaniels · Mar 7, 2021

umrotzer said:
It's a PAL system and the BIOS should be untouched, where is (Or should be) the bridge location u are talking about.

The trigger is OK if i press it together without top cover on it acts like it should. To tested it I have put the laser all way to the end and if I close the trigger by hand the laser moves all the way in, tries to focus (Lens up/down) but no spinning. The same process also happens with cover on I can hear laser moving aso, so the switch should be good.

i see i'm mistaken there, since it's around the time of my snes i thought sega did the wiring most likely the same, but sega used a DC powersupply, where nintendo used a AC one.
Most common isseu seems to be the laser no seeing the disc at all.
are you sure the new laser is not only moving correct but als scratch free, no obstickles and angled right?
try a music CD to test..

umrotzer · Mar 7, 2021

JaapDaniels said:
i see i'm mistaken there, since it's around the time of my snes i thought sega did the wiring most likely the same, but sega used a DC powersupply, where nintendo used a AC one.
Most common isseu seems to be the laser no seeing the disc at all.
are you sure the new laser is not only moving correct but als scratch free, no obstickles and angled right?
try a music CD to test..

Ive put in an audio CD but same like with a game, I also barley closed the lid so it things it closed but no disc spinning at all, not even a try. And I checked if the cd can spin freely and is not to close to the laser

JaapDaniels · Mar 7, 2021

umrotzer said:
Ive put in an audio CD but same like with a game, I also barley closed the lid so it things it closed but no disc spinning at all, not even a try. And I checked if the cd can spin freely and is not to close to the laser

this video is the most complete info i could vind.

i never had a sega megadrive, nor any console that ever worked with CD's, so i can only help you this far.
i'm a mechanic in electronics for working, but just never ever had to repair a CD-drive.

umrotzer · Mar 7, 2021

JaapDaniels said:
this video is the most complete info i could vind.

i never had a sega megadrive, nor any console that ever worked with CD's, so i can only help you this far.
i'm a mechanic in electronics for working, but just never ever had to repair a CD-drive.

I've already watch that xd. But thx.

I've uploaded some pictures maybe that is more helpful

JaapDaniels · Mar 7, 2021

umrotzer said:
I've already watch that xd. But thx.

I've uploaded some pictures maybe that is more helpful

Not to me, sorry, but there's got to be someone on this forum with more knowledge of your device.

umrotzer · Mar 7, 2021

All good, thx for your help and maybe someone else has an idea

Joosh13 · Mar 8, 2021

As not fun as it sounds, you may wanna start checking traces with a multimeter. Just do a current check, make sure things that are supposed to be connected actually are connected. Worst case you can repair a broken trace. Next would be the actual ICs somehow, though I would assume the MDCD somehow has a check it does to see if theres anything in the drive, which is what I assume would be faulty considering when you give the motor and other stuff power it works (ie the motor/band/gears arent bad)

It isn't something I am super familiar with but I do know CD drives a little and def know early 90s consoles somewhat (not an expert just an enthusiast/techhead lol)

umrotzer · Mar 8, 2021

So let's go to the "fun" part xd

umrotzer · Mar 10, 2021

OK so final update, after found a new repair video on YouTube, I finally got it to work. And this guy was the first person I've seen that has mentioned it when replacing the laser.

I never knew that u need to remove a little solder bridge that soldered for transport reasons. So after I removed the bridge all was totally fine. Except that on the button of the screen are some graphic glitches, so maybe I need to do a recap.

Anyway thanks for all your help guys

Sega Mega CD 2 PAL no disc spinning.

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