Sega Saturn Model 2 reads discs as audio - drive board issue

[Saskatoonguy]

So I already asked this question on another Saturn forum (apparently there are more than one... I was shocked) so I just copied my troubleshooting notes from that site. I hope this is alright. I also posted updates after the first post so I copied the second post after the first. If you don't want to read it all and skip to the point, I isolated the issue to the drive board. I just do not know how much further I can isolate the issue.


"I am having an issue with my Saturn. It is a US Model 2, JVC Laser assembly. I am still fairly new to Saturn's and not that good with electronics so bear with me.


-The unit powers up and sees discs but it only sees game discs as audio. The unit has a hairline crack inside the disc tray on the top cover, it barely goes through the plastic and it is still solid, the plastic hasn't separated. This leads me to believe the unit might have been dropped at one point.

-The menu blocks are green. They respond properly to audio playback. The greed LED on the front stays solid green, no blinking.

-I have replaced the laser although I think the old one is still fine. I have adjusted the laser pot from 1300 down to 500 and put it back to just under 1000. The issue happens at 500 so I brought it back up to 1000 to give the laser some life. I am quite certain the issue is not the laser actually seeing the discs.

-When I play the audio it recognizes off of Daytona USA it stalls on the later tracks. This makes me think it is the laser not getting far enough out to read the signature, so it cannot play the later tracks of a disc. I haven't been able to find much for tech info but I did read enough to gather how the Saturn boot process happens.

-I have another Saturn (I got this one to mod) and this one seems to make more drive noise when spinning this disc, it sounds like there is a grinding inside. I didn't notice anything terribly off when I was inside it before, what should I be looking for?

-Booting a game takes a long time before the unit finally goes to the menu, it takes another minute before the screen locks up and it takes a second to boot the game as an audio disc. The unit sounds like something is going back and forth when trying to load games. I also have a dead battery in it, so I have to go through the setup screen as well. The disc appears to be spinning fine when in the setup screen, I don't hear the grinding mentioned above.

-I tested every single US game I have, as mentioned above Daytona USA eventually stalls and loads as audio, the later tracks stall and won't play. Mr.Bones disc 2 boots fairly quickly, and plays fine, I think this is because it recognizes it as an audio disc almost immediately. This is one of the games I know plays in a CD player. It plays fine right up to the end of the disc. No grinding sound. The same cannot be said about disc 1, that disc responds as the other games do. When I play back the audio available off of it it stalls out on the higher tracks just like Daytona USA. Tomb Raider is the same way.

-Magic Knight Rayearth, Shining Wisdom, and Albert Odyssey all attempt to load before eventually stalling at the menu trying to recognize the disc and sees it as audio. The audio doesn't play, although I think that is normal for these games to fail as audio CDs. The same thing happens for Sega Rally.

-Actual audio discs load fine, the drive sounds like it is spinning normally without any kind of grinding for the first couple tracks, but they stall on later tracks as well and you do hear the grinding as laser moves around trying to find the later tracks

-I found this info (below) on another site so I attempted this, it really had no effect on the unit so I put the two pots back where they were. The post also offers very little information in regards to value or exactly what he is adjusting, he mentions multiple variable resistors but the left facing one is a switch from what I think. I believe the upward facing resistor adjusts the disc speed. Here is what I read.

""I know what's causing the problem--the spindle motor for the CD's doesn't spin fast enough to read the disc properly; this usually happens when the system gets hit too hard or is dropped. This causes games to recognized as audio CD's and also causes the tracks to play improperly (there will be complete silence when a track is played and possibly some static at the beginning and the cubes an the sides of the display will be distorted and blown up.IF THIS DOES NOT HAPPEN THEN DO NOT ATTEMPT THIS.)Before starting, make sure the system is plugged in, there's no controller connected, and the system is NOT hooked up to a tv. Okay, now this is where it gets complicated. first, take the top of the system off and locate the disc drive switch. Depending on which model your console is, it'll be in different places. On the newer model (the one that has a PC board on the top cover), it'll be on a small PC board on the opposite side. On the older model (the one that has all the PC boards on the bottom), it's sticking up out of the metal plate between the two PC boards(the little clear plastic thing with copper plates inside). Either way, the switch needs to be held down or taped down.(I suggest taping it, but it may not work with the older system.) There are a few little variable resistors (little upright disc-shaped things) on the top left corner of the exposed circuit board (the one with the CD lens on it). Try adjusting those with a small flat-head screwdriver with the system turned ON and a CD on the spindle. Be CAREFUL--do NOT touch the CD while it's moving and keep your hands away from the PC board on the left--It WILL shock you. Adjust the resistors untill the CD spins the fastest. If the CD stops spinning, pull off and then replace the tape. If it doesn't spin at all in the first place, check the tape. Once you get it spinning as fast as possible, hook the system back up to your television WITHOUT replacing the cover. If it reconizes the CD as a game, your done and you can close it up. If it thinks its an audio CD or doesn't read it at all, the resistors need more adjusting. This work can be very trying and dangerous; this method can also ruin your system, but it's the only way to make it work without replacing any parts, but it DOES work. If you have any questions, ask me.""



So at this point I am left scratching my head, I don't really want to toss the unit, it cost me more to ship it to me than it did to buy the darned thing. I do not think the unit is FUBAR but I am not an expert. I am still leaning it towards some kind of mechanical failure with the laser gears but I honestly do not know what to be looking for. So I am starting here for assistance, if anybody knows any other Sega Saturn sites that might be of assistance please point me in the right direction, this is google's #1. Sorry if my post seems a little scatter brained.

Any help is greatly appreciated! Save my Saturn! "


Update
"Ok, first and foremost, I installed the working drive on the broken unit and the unit runs properly. So my issue lies within the drive board somewhere.

-I swapped the known working laser with the broken board and it still failed to boot discs. I didn't adjust the laser strength but I figure the results would be the same so I put the laser back into the working drive.

-I put the laser I originally got with the Saturn back into the unit as my initial tests with it in were quite brief. The original laser goes through the struggling boot process like the replacement but when it finally recognizes the disc it shows 1 track with a play time of 999:59. I adjusted the pot but I never tested in my working Saturn, this laser might be FUBAR.

-I noticed black top of the broken drive/laser seems to rest at a slight angle compared to the working drive/laser. It leans toward the front right.

-The laser is definitely moving to the edge of the disc to check the signature, but when the laser is checking the signature it rapidly adjusts up and down. It isn't seeing that signature. I tested 3 lasers and they all had the issue, so I never opened up the laser to check the movement assembly (whatever it is called)

-I reseated the ribbon cable on both ends of the laser and drive board just to be safe

-I noticed the drive on the broken unit was spinning much faster when compared side by side to the working unit. I am wondering if I altered the resistor a little too much. Anybody know what those values should read, or if I can even read them and how?

At this point I know my issue lies within the drive assembly but what parts are available these days aside from the laser itself without scoring a whole new unit? How much further can I isolate the issue at this point? I am starting to think it might be a bad chip that isn't allowing the unit to boot but I am far from qualified. Is there a resource for S/N's and board models so I can try to buy a proper replacement unit instead of two duds that can't swap parts if that is the end result.

Thanks once again, this help is greatly appreciated. "


If you skimmed it all to this point just read my last paragraph please, it sums it up nicely. I did find a S/N list, I just need to figure out how to tell what motherboards each serial corresponds to so I can swap in a new drive if I can find one. I would like to fix the current one but I don't even think I can at this point. I have been told there are people that sell entire drive assemblies but I have yet to find them. I would prefer to buy a working part than a whole other unit and hope I have a working drive in the new unit (I have to source of ebay).

Sorry for the giant post but any help is greatly appreciated, I have yet to see an actual fix to this issue online.

[Saskatoonguy]

Ok, so for specifics the drive is a v.0014 PCB board, 21-pin ribbon cable, 32-pin. The motherboard is a VA6. I have even snapped a pic for visual confirmation.

At this point I am giving up on the drive and trying to a replacement part but if anybody has any suggestions I am open to trying to salvage anything I can.

Thanks for reading and I hope this info can help someone else one day.

[spiritplx]

Sorry, I won't be able to offer much help here, but I think you are on the right track for diagnosing the issue. Just keep swapping parts until you narrow down the specific component that is failing. At that point, you can either trash it (probably your best bet), or try to fix it (most likely not worth the trouble). If the piece can be purchased and replaced, great, otherwise you will just have some spare parts for your working Saturn.

Best of luck.

[Saskatoonguy]

Well, I have accepted the drive has failed and have a new drive on the way. I paid $8USD for the drive, quite fair, but almost as much as I paid for the broken Saturn. This is the furthest anybody on the internet has diagnosed this issue, I am not the first person to experience the issue. Here is a concrete answer until somebody can find out what specifically on the board is failing. Your drive is FUBAR, swap out a good one and your Saturn should be running like new. Hope this help somebody else.

[Saskatoonguy]

Ok, so this Saturn has finally been repaired. I scored another drive off a fellow racketboy member, that appeared to be the only repair option left. Maybe if I can find something about this in those repair manuals that are getting posted soon but I doubt it.

Basically there was something on the drive board preventing the games from booting, it couldn't read the disc signature. I don't know what is failing more specifically than that. I really hope this can be useful to somebody else in the future.


I do have one slight issue remaining with the unit, certain games do not boot (Vampire Savior, Sonic Wings Special, Sonic Jam JPN). I have adjusted the laser strength to considerably higher than where it is when running the other games to no avail. The laser I used is previously used though, so I am just thinking it is a laser issue. I will test this when I get some time but for right now it is nice having the unit closed and running. I will make another thread if I cannot get it running.

[Curlypaul]

Can I ask, was the drive straight out of another Saturn, or was it a new part?

Just interested because the last time I looked into this nobody was sure which laser assembly would plug in and work

[Saskatoonguy]

I got the whole drive from another Saturn. Motherboard revision VA6-VA9 have compatible drives regardless of region to my understanding. I am pretty sure this came off a VA8 Saturn. I do not know which other ones are compatible with each other. I only have VA6-9 revision Saturns. I couldn't find the part new, only the laser is still manufactured to my knowledge.

The laser itself is just a standard Optima 6S. I think optima 150S work as well but I don't know for certain. This is of course a JVC assembly.

Hope that helps.

[Curlypaul]

Yeah thanks. All my saturns work atm, but good to know for future reference