Sega CD systems repair thread

[omp]

Nice pictures by the way!

[Drakon]

Nice pictures by the way!

Well I know what it feels like to follow a guide using blurry pictures. A little patience and playing with lighting makes a big difference.

[stlpaul]

OK, I got a new laser, put it in and no luck. Same problem as before I can hear the disc spinning and "laser reading" sounds like CD players usually make, and then I hear occasional physical knocking and buzzing sounds... the Sega CD never kicks the disc out or gives me an error, it just tries to read forever. Same thing happens for Sega CD original game, Sega CD-R and Audio CD.

So, in summary: Sega CD 1. It powers up normally, ejects and closes the tray normally, disc spins and it sounds like it tries to read but does not succeed. The disc drive makes weird knocking and buzzing sounds from time to time as it tries to read the disc. I have replaced the belt and the laser (KSS-240A). From visual inspection when I had the device open, capacitors look good, gears look good, clips look good, as far as I can tell (I am not an expert). I am the original owner of this Sega CD (still have the original box and everything) and it worked normally until sometime in the early-mid-90's when it stopped being able to read discs. It has never been dropped down a flight of stairs or had orange juice spilled on it or anything like that.

Anyone have any ideas about what I can try next? Thanks for the help.

[omp]

I believe this should be the last capacitor list?

Main Board (I hope you have a lot of 50v 10uF caps laying around lol!)

C104 50V 10uF
C107 50V 10uF
C110 50V 10uF
C115 50V 10uF
C122 50V 10uF
C127 50V 10uF
C129 50V 10uF
C131 50V 10uF
C132 50V 10uF
C139 50V 10uF
C201 6.3V 100uF
C206 50V 10uF
C207 50V 10uF
C208 50V 10uF
C209 50V 10uF
C210 50V 10uF
C220 50V 10uF
C221 50V 10uF
C222 50V 10uF
C228 50V 10uF
C229 50V 10uF
C232 50V 10uF
C233 50V 10uF
C234 50V 10uF
C235 50V 10uF
C236 50V 10uF
C237 50V 10uF
C238 6.3V 100uF
C239 50V 10uF
C240 50V 10uF
C301 6.3V 100uF
C303 6.3V 1000uF
C305 16V 330uF
C306 6.3V 100uF
C400 50V 0.47uF
C401 6.3V 100uF
C413 50V 10uF <<<< This one may be a bitch to do as it is between the MD to CD connector and the heatsink

CD drive

C501 6.3V 47uF
C507 6.3V 47uF
C508 16V 100uF
C510 50V 1uF
C543 16V 10uF
C546 16V 10uF
C548 6.3V 100uF
C551 16V 100uF
C581 6.3V 47uF

[jriquelme]

wow! Nice work. Thanks

[Guntz]

Okay I fixed my sega cd completely. Keep in mind this's the first segacd I've ever seen and I just got it yesterday...like I was with the 32x guess I'm a fast learner. I bought this segacd on ebay (for really cheap) with it listed as "factory refurbrished, gauranteed to work". When I plugged it in and fired it up I was presented with this lovely scratching noise of the cd constantly scratching against the case as it spins, also it would get to the sonic shooting fireworks screen and then freeze. I tried some old audio cds and I only got one to actually play (while scratching against the case), it wasn't a burned cd, store bought one. First I needed to fix the scratching, I used some foam to raise the entire cd assembly and that worked, I found sticking some nice prop nuts looked nicer though (and won't ever depress in the future like foam will):

This cured the disc scratching against the case, then there was the issue of getting this sega cd to read discs. I managed to get a burned copy of final fight cd to load once every 50 or so times, the in-stage music wouldn't play though. I tried jeroi's "sensibility" pot that didn't do anything. Tiido said adjusting the other pots would brick my segacd for life and that I need a scope to adjust them properly. Since my segacd was already just a glorified cd player and I'd wind up sending it back to the seller anyway I decided to go against the warnings of tiido and mess with these pots anyway. The pots are numbered:

Naturally I decided to start with #1. Turned it to the right, same thing as before, turned it to the left, whole thing worked like it's brand new. Since I have zero clue of what this pot actually does I turned it to left the minimal distance to get it running okay. Here's how the pots came:

And here's how I set the pots to get it working:

Re-assembled:

Running like a champ:

For all I know pot #1 could adjust the laser strength so the less you need to turn it to get the thing working the longer the laser should last.

Also jriquelme: You're lucky we both have the same model. Here's the "sensibility pot" jeroi keeps saying to play with:

When I turned my "sensibility pot" it made the cd drive start clicking like yours is, so that's probably your first problem right there. This picture is how mine came but I wound up having it facing perfectly upright (a teeny bit more left of how it came). Also try setting all the other pots to how mine are set and see if that fixes your segacd (it worked for me so it can't hurt).

I've got a broken Sega CD that looks like yours. The laser and motors work. The laser moves to track 0 to read the disc, but the CD never spins. The laser probably can't see a disc. Do you think increasing pot #1 will fix my problem? I'd like to try it, but I will have to replace the burnt motor controller IC before doing so.

[Moirai]

I've got a broken Sega CD that looks like yours. The laser and motors work. The laser moves to track 0 to read the disc, but the CD never spins. The laser probably can't see a disc. Do you think increasing pot #1 will fix my problem? I'd like to try it, but I will have to replace the burnt motor controller IC before doing so.

could the motor be broken?

[Drakon]

I've got a broken Sega CD that looks like yours. The laser and motors work. The laser moves to track 0 to read the disc, but the CD never spins. The laser probably can't see a disc. Do you think increasing pot #1 will fix my problem? I'd like to try it, but I will have to replace the burnt motor controller IC before doing so.

Honestly I havn't tinkered with it that much. I rotated the pot, and it worked, and I looked up to the sky and thanked the sega gods. I wouldn't say I'm any expert.....but turning #1 did certainly make it go from "can't read 99% of discs" to "I can see cleeeearrrly nowwwwww the rain is gonnnneee". Although the thing was spinning discs before I turned it. The good news is nothing bricked from turning #1 or the pot on the laser itself so I don't see how it could hurt to try.

[Guntz]

Which motor? I already said the two motors (CD spindle and laser sled) work. The laser sled moves, the motor spindle works on a different Sega CD drive board and so does the laser. The thing just wouldn't spin the disc. I'm gonna try replacing the burnt motor controller IC again and try those pots.

I replaced the old motor controller, but the new chip shorted inside and burnt a bit. I have a spare, hopefully I can get a swap done again.

[Drakon]

Which motor? I already said the two motors (CD spindle and laser sled) work. The laser sled moves, the motor spindle works on a different Sega CD drive board and so does the laser. The thing just wouldn't spin the disc. I'm gonna try replacing the burnt motor controller IC again and try those pots.

I replaced the old motor controller, but the new chip shorted inside and burnt a bit. I have a spare, hopefully I can get a swap done again.

Also how do you know the motor controller ic is "burnt" exactly? Did you stick the laser in a working unit and have success with it? Also perhaps there's a short on the pcb which is what shorted the first chip and the one you just replaced it with.

[MEGADRIVE Jeroi]

OK, I got a new laser, put it in and no luck. Same problem as before I can hear the disc spinning and "laser reading" sounds like CD players usually make, and then I hear occasional physical knocking and buzzing sounds... the Sega CD never kicks the disc out or gives me an error, it just tries to read forever. Same thing happens for Sega CD original game, Sega CD-R and Audio CD.

So, in summary: Sega CD 1. It powers up normally, ejects and closes the tray normally, disc spins and it sounds like it tries to read but does not succeed. The disc drive makes weird knocking and buzzing sounds from time to time as it tries to read the disc. I have replaced the belt and the laser (KSS-240A). From visual inspection when I had the device open, capacitors look good, gears look good, clips look good, as far as I can tell (I am not an expert). I am the original owner of this Sega CD (still have the original box and everything) and it worked normally until sometime in the early-mid-90's when it stopped being able to read discs. It has never been dropped down a flight of stairs or had orange juice spilled on it or anything like that.

Anyone have any ideas about what I can try next? Thanks for the help.

You seem to have similar problems that Drakon did. How ever he had broken supports and so. You may have to poke with the pot. Can anyone trace the pot and see where it goes so that we could figure what it does?

[Guntz]

Also how do you know the motor controller ic is "burnt" exactly? Did you stick the laser in a working unit and have success with it? Also perhaps there's a short on the pcb which is what shorted the first chip and the one you just replaced it with.

The chip I soldered in place eventually started smoking and smelt terrible. I think that qualifies as being burnt. Yes I did use the laser on a working Sega CD and it worked. The only bad part in this Sega CD is the CD drive PCB, from what I've deduced. Even the ribbon cable is good. I should try the pots, I never touched them in my tests and I really should have. It'd be nice to fix this Sega CD.

[Drakon]

The chip I soldered in place eventually started smoking and smelt terrible. I think that qualifies as being burnt. Yes I did use the laser on a working Sega CD and it worked. The only bad part in this Sega CD is the CD drive PCB, from what I've deduced. Even the ribbon cable is good. I should try the pots, I never touched them in my tests and I really should have. It'd be nice to fix this Sega CD.

From your description it sounds like the pcb is shorting, carefully inspect the pcb for it the short is there somewhere. Is the motor controller IC a common purchasable part or some custom sega only thing?

Jeroi, I tried looking at where the pots connect but without taking the whole thing apart I don't think that's happening. There's a chance the pots connect to an IC somewhere that controls something on different pins, so following the traces may not even help you figure it out.

Anyway to clarify I'm no expert in any sense with this hardware. So here's all the info I found out based on growing a pair of balls and doing what I was told would permanently brick my segacd. If your sega cd hardware looks like mine:



Then you can use my suggestions to help make it run better, otherwise I don't know if this stuff would work on a different model or not. This's the first sega cd unit I've ever seen in my life, I have zero experience with any other model or pcb revision of the sega cd. If you want to send me a non working sega cd that's a different pcb revision for tinkering then you're more than welcome to. Within a few hours my sega cd went from reading nothing to everything with just these few easy steps:

The circled pot is the one I adjusted in that row it's labelled as "1"



The other three I left them how they came. If your cd unit doesn't have 2, 3, and 4 rotated to the same spots as mine, then you can try setting them to how mine are set. Keep in mind I have no clue what any of these pots do and I don't know if messing with pots 2, 3 or 4 will break your segacd or not so try adjusting pots 2, 3 and 4 only at your own risk. I have zero experience adjusting pots 2, 3 or 4 so I have no clue how safe or unsafe it is to play with them. If your pots 2, 3 and 4 are the same as mine then great, seems to work for me. Once again here's how all the pots came (the circled pot is the one that needed adjusting to get the sega cd to read more than one random music cd):



Turning pot #1 to the left made the system go from "I can barely read anything" to "I can read all discs w00t!":



You can adjust this pot all the way to the left it still works great. I just figure on a cd system you should only adjust things the minimal amount to get it running, last thing you want to do is set your laser strength so high that it'll wear out your laser in a week.

Besides pot #1 the only other pot I adjusted was the jeroi "sensibility pot":





You've seen it in theatres (or perhaps on dvd or even vhs if you're in a poor country that somehow has internet), now you can experience it at home on the sega cd.

Adjusting this "sensibility pot" made it so the sega cd stopped making this annoying clicking sound and was able to start playing audio tracks much faster.

I messed with pot #1 and the sensibility pots and adjusted them all the way from one side to the other and fired up the console. Both of these pots didn't fry or brick anything so adjusting them doesn't seem to immediately hurt the sega cd or the laser in any way. Since the sega cd is a sensitive cd unit I recommend against adjusting things as far as they go, just adjust them far enough to get it working.

This message has been brought to you by Drakon, the only guy who wasn't afraid to rotate a couple of pots and see what would happen. Approaching "risky" stuff as carefully as possible sometimes turns out to be a good idea like in this case. I'm sure I could have replaced caps and the laser unit all day long like how some people do, but living a little on the edge seemed like a better idea. Of course I was careful to take clear pictures of the pot positions before adjusting anything, this way if I did manage to somehow brick the sega cd laser then I could atleast adjust the pots back to how they were.

How to know if you need to adjust these pots: If your sega cd is spinning the disc but it either reads nothing or maybe 1-2 discs if you're lucky (mine was reading only one random audio cd).

How to know which way to adjust the pots and how far: You don't, the whole point of having a pot is because each system needs to be adjusted differently. The whole reason why you you have this huge range of adjustment is because some systems need to be adjusted one way and others may need to be adjusted the other way. I adjusted the #1 pot and the "sensibility pot" all the way in both directions and nothing bricked so if you're adjusting only these two pots then it should be safe (it was for me!).

Why are the pots there?: For adjusting stuff. Obviously you want to adjust things as carefully as possible but these pots are indeed intended to be used to adjust properties until your cd drive functions again. This's why I hate optical drives, they need to be carefully adjusted, and when they get older, they need to be adjusted again. Obviously if there were levels that worked with every laser of all ages then you wouldn't get a row of pots to fiddle around with.

Should I replace the caps on my sega cd?: If you're afraid the rotate the pots then I don't see why not.

[Guntz]

From your description it sounds like the pcb is shorting, carefully inspect the pcb for it the short is there somewhere. Is the motor controller IC a common purchasable part or some custom sega only thing?

I don't even know if the old chip had shorted out. I just though, well if the chip is getting super hot, it must be shorting. But then afterwords I checked another working Sega CD and it had the same super hot motor controller chip, which is really weird. All I know is the replacement chip I installed burnt up. I never tried any of the pots. Maybe one of them determines how much power that motor controller has to put out.

[Drakon]

I don't even know if the old chip had shorted out. I just though, well if the chip is getting super hot, it must be shorting. But then afterwords I checked another working Sega CD and it had the same super hot motor controller chip, which is really weird. All I know is the replacement chip I installed burnt up. I never tried any of the pots. Maybe one of them determines how much power that motor controller has to put out.

Try setting all your pots like mine?