Sega Mega CD Model 2 not reading disk

I just got my old Sega Mega CD out and fixed the infamous "fuse blown" issue the Model 2s are known for. My issue is that it now won't read my disks. The system powers up and goes to the CD splash screen but nothing more. I get a "Press Start" notice then go to the music player screen. I opened it up to see what's going on and here's the rundown. It is a second revision model 2 with the Sony CD drive connected by a single ribbon cable. The laser lens is moving trying to focus and if the laser cart is moved toward the outer edge of the read area, it will go back toward the spindle so both those work. It just won't make any attempt to even try spinning my CD at all. Before anyone says anything about running it open with the disk lid switch being open, I bypassed it with a little jumper. The CD assembly has this part number on it: KSM2401AAN Any one have any ideas about this? If it's fried, anyone got a replacement for it? I found a brand spanking new Sony CD drive assembly on eBay with same part number for like $12 but there's no picture with it.

 

Replace the capacitors.

90% of the time that repairs the unit completely...

 

Thought I'd give a little more info on my problem. Here's a picture of the CD drive. I'm not sure but it looks like the disk spindle might be spaced up a little too far and that might cause it to not spin at all. Any one know about the disk height for the model 2 second revision Sony CD drive equipped MCD? Thought I'd share this before I go replacing all the caps. I counted 35 10 uF 16 volt models along with a few other bigger ones. I hope I have that many caps lying around...



Sorry for picture quality. Crappy cellphone camera...

 

That does indeed look wrong. The right height is approximately 2mm from the top of the plastic shield that protects the top of the optical pickup.

 

Thought so. I'll try to see if I can get it back down before I go solder frenzy with the caps. The unit came like this off eBay with seller claiming it to be in working order. (thanks a lot idiot.) :mad-new:

 

Well I got the spindle back down to where it belongs. A little under 2 mm clearance to laser and still nothing.



Time for some new caps. Ones rated for 50 volts should work right? It's mainly the uF rating that counts, correct? Found a site selling 10 uF 50 volt electrolytic barrel caps for $.05 each. (SCORE!) Here: http://www.twistywristarcade.com/capacitors/234-10uf50v.html These and the few other sized ones and I'll have all the caps I need.

 

Did you see my post in the repair/restoration thread? It seems with mine there is an issue with the laser sled. When I got it the 4 pots on the board had been played with and getting it sorted will be a bitch/expensive. At least I got 1 working unit out of 2 I suppose....

 

No didn't see. I'm waiting on new capacitors for that one. Got another one. The first revision model 2 I believe. It's the one with 3 cables from CD drive to main PCB where the laser pots are. Same issue. It boots, goes to BIOS screen and nothing. The access LED is blinking on it non-stop. I opened it up and started checking things. The laser is working as I can see it using my phone's camera. Very bright on the screen. It tries to focus on the disk. The sled works too. I checked voltage and it shows almost 4 when the sled moves to the park position. The Disk motor shows no voltage what-so-ever. Could this be more bad capacitors or does the drive not move until the laser detects disk? If so, then what gives? Not all capacitors could be bad since the laser and sled seem to be working correctly.

 

Did you get a red light from the laser?

 

Hmmmm not sure what that could be. I was lucky, I just trolled ebay until I found someone with a Sega CD2 for sale that had the black CD spindle (rev 4102-A). It was sold as a "faulty" lot, so got it from the USA (to Australia) for cheap.

I had another 2 early revision Sega CD2's and these had the Samsung laser, have you had a good look at the 3 looms? Did you accidently swap 2 of the looms over? Is one of the wires broken? On one of mine a single wire was broken, I just repaired it so I don't know what issue's it would have caused before hand.

 

Yep, laser light was red. Barely able to see it with naked eye. It showed up as purple on camera like infrared does. Interesting thing though is that it looked like a bunch of brighter spots of light in a dim red circle of light. Don't know what that means. Here's some photos.

Here's the lens. Sorry for blurriness. Camera seems to be affected by the slightest of movement.


This is the photo of the laser lit up. The room I took this in is very bright and this is even brighter.

I left the 3 looms where they go. Here's a picture bellow. No busted wires. I'm giving up on these 2 CD drives since bart_simpson has made an offer to me for a swap.

The left wire goes to the laser, center one goes to the laser lens adjustment. Last one goes to the sled and spindle motors. This is how they were when I got it.


Finally, this model has this little PCB on it. Not sure if this was stock or some sort of region mod done by last owner.

A top down view of the whole PCB. The little circuit in question is clearly visible in tan-ish color.


Close up.


The numbers on the chips are: HD74HC04P 3D25 for top one and HD74HC74P 3B16 for bottom one. PCB has these numbers on it: BE2200F01003 1251V

Let me know on this one if anyone could.

 

Yep those boards are stock, mine had them too.

 

That's surprising. Must've been a glitch in this revision and it was fixed with this little circuit. Sure looks a lot like some sort of region mod chip don't it?

 

Only to the untrained eye as I once made the same mistake too.

I have a SegaCD 2 that I fried who has the same type of laser. I don't know if it works but if it did I'd need to rewire one of the connectors that I rewired for an X'EYE. Thankfully it is a very easy fix.

 

The tiny board is a quick fix for a design error on the large 201 pin SEGA ASIC.

 

^ I thought so.

 

I'm having a similar issue, except I can watch the head move toward the spindle and then the gear starts grinding, like the stop sensor isn't working. I managed to get it spin up by taking a hook and pulling more on that reed switch under the drive. Anyone know how to fix this issue?

 

^ I don't know about your issues but the model in the pictures above with the little extra circuit board turned out to be working. I made the mistake of trying to use a burned copy of a game on it for my initial tests. Despite following the guides really carefully I musta done something wrong or these models hate CD-R media...

Anyways, I bought Sonic CD and tried it on the one in the last pictures above and the system lives. Even the battery for the on board save RAM lives. Despite being a bit noisy and slow on some of the DAC music like the level complete sound everything works perfectly. The first model I have with the Sony CD drive seems to be dead still. May have to fart with the CD head height some more soon.

Now if you'll excuse me I have some time stones to collect and timelines to restore.

PS: Anyone know how to burn copies of this game off? I want the hacked game called Sonic CD++ but I want the Japanese or European version since I like the music tracks on these version better than the US release of original game. I also need it to be NTSC and English language. It also needs to play on original hardware. Anyone got tips on doing this or willing to take a stab at it? I know where to get the ISO of the game for all 3 regions as well as the CD musical tracks. I played this setup a lot on Kega Fusion. Now I wanna do it with the real deal. After all, I have nearly 200 hacked Sonic games on my Everdrive MD cart that play fine. Can't see why this wouldn't be with a little fudging.