Crazy Saturn

Hi,

This has been bothering me for a while so I thought I'd ask some advice. My saturn has been 'playing up' recently and sometimes refuses to load games at all, other times it'll load them no probs. The disks are clean and scratch free and I have used a CD lense cleaner on the Saturn with no luck. I turned up the laser intensity but with no effect. It plays FMV fine which leads me to believe that it's not the CD drive. Also, sometimes during a game the Saturn will crash and go to a black screen. This sometimes happens during the BIOS screen aswell. My saturn is in great condition and has no mod chip and has only been opened once - to up the laser intensity. Any help would be greatly appreciated. Thanks
 

Taelon

Member
Sounds like an actual hardware problem, rather than a CD drive issue... If this gets any worse, your only recourse may be another Saturn... I do hope I'm wrong.
 

Curtis

Member
I have a theory about this...

Several of my own Saturns have had a similar problem - refusing to load certain games (either CDR or Original) - and I too believe it has nothing to do with the CD drive. When I swapped the CD assembly with one I knew worked, it stopped working. The "non-working" CD drive worked flawlessly. That leaves only two other major components - the motherboard and the power supply. If it's the motherboard, you are screwed - there's nothing you can fix on there really. My theory is that the power supply contains some components that are failing and it no longer generates the correct voltages constantly. When I get a bit of time, I plan to swap a powerboard around to see if this has any bearing, so I'll let you know if this helps me. Hopefully it will, and this will be of use to you...
 
I'm not sure, I think it's something to do with loose conections in the wires that conect the laser to the motherboard - that's why it's only certain games... [ie some games will need to read a bit on the CD that pull the laser in a certain direction]. I've also tries to change the CD drives in two working Saturns and both refused to work with the other MoBo. Then again, I have no clue about how a SS works
 

Curtis

Member
I see what your theory is, but what I'm saying is that when I swapped the two CD boards in my Saturns (one working 100%, one working like yours is), the behavior of the non-working Saturn didn't change - it still didn't work. Conversly, the working Saturn continued to work normally. When I changed the boards back, the behavior stayed the same.

I don't know how the Saturn really works either.
 

Megazoid

New Member
I had a similar problem, and it was a stepdown converter (220V->110V), when I changed it to the new one Saturn started to load games again without any problems.

If an external transformer is a problem, an internal one could be too.
 

Taelon

Member
That would almost definitely point to heat being a problem. Or, as it were, a solution.
One more for the power supply - it would generate the most heat of any component in the Saturn, so swapping it should do the trick...
 
I don't think it's heat because before I tried leaving it on I had tried putting a hot water bottle below it. That would have created more heat than the PSU.
 

Curtis

Member
Well, I finally got round to some tinkering.

I opened up the non-working Saturn and tested the power rails - 0V (check), 0V (check), 5V (check), 5V (check), 11.8v. 11.8V? What the hell? Opening up the working Saturn, revealed that the rails tested a more normal 0,0,5,5,9 (.5ish). So I switched the supplies over and hey presto! One previously non-working Saturn suddenly works flawlessly. I haven't tested this exhaustively, but the one game that consistantly never loaded, Andretti Racing, loaded first time. Conversely, the previously working Saturn started to show the exact same symptoms that the non-working one showed. Namely, inconsistant loading of games. Woohoo! Problem identified!

My theory is that the over-supply messes with the timings of the drive causing the game to crash when the laser is in the wrong place at the wrong time.

All I have to do now is isolate the faulty components on the supply, replace and tell you how to do it.


Hope this is of some use to you.
 

Curtis

Member
I've spend a good few hours with my dad pouring over the power supply and I'm not really any closer to finding a solution. I'm no longer confident that it is a simple matter of correct voltages, because according to the writing on the bottom of the board, the rail that I think should be 9V should in actual fact be 12V. This just confuses the hell out of me, because the board that works is the one that supplies 9V. ???

I'll borrow a CRO sometime soon and see if I can determine the quality of the supply. The board that provides 12V (and doesn't work too well) seems to fluctuate quite a bit depending on what the CD motor is doing, while both 5V rails stay rock solid.

Will keep you posted...
 

Taelon

Member
I'm sure that the correct output voltage should be 9V, not 12V ... But maybe the board is in fact supposed to generate 12V initially, then send that through a voltage regulator which would stabilize it at 9V. Just a thought... See if you can find such a beast...
 

Curtis

Member
Yes, I've been looking at this as a possible cause. However, there definately isn't a single component that acts as a voltage regulator, so that makes things a little more difficult. I already know that it's not leaky electrolitic capacitors, which is a shame because it's an easy fix. I'm currently looking at a transistor marked 3311 (2sc3311) as a possible faulty component...

The CRO's on it's way, so I should have some clearer answers soonish.
 

Alexvrb

Member
I'm having a similar problem. Not as bad though, but I often have to reset it to get it to read a CD. I'm wondering if an iffy PSU + a mod board is a bit too much for it. Are the more common Sat PSUs compatible with those of any other consoles, meaning what are the replacement options? Or would we have to identify (as you're attempting to do) problem components and replace them ourselves?
 

Curtis

Member
I doubt that Sat power supplies are compatible with anything other than a Saturn. The damn things are to finicky - my information (dad) says that you really have to know what you are doing to design one. Especially with switch mode power supplies like the one Saturns use.

OK, now I'm going to contradict my previous post. After examining the faulty supply with a CRO, I've discovered that it is probably the 5v supply that is at fault. When the supply is under load, one (and only one) of the 5v rails would fluctuate by around +/-200mv when the CD motor is spinning and the laser head moving. Given that the 5v is probably used to supply the electronics of the Saturn, a fluctuation of this magnitude would very like cause some problems(i.e random crashing - especially on games that move the laser around the disc alot). The other rails of the faulty power supply stay fairly stable.

On the working power supply, these variations do not occur. All rails stay rock-solid no matter what the drive is doing.

It would be a reasonable assumption that the 12v reading on what should be a 9v rail on the faulty supply is just a symptom of a faulty 5v rail.

This brings me to a possible solution. There is a small transistor on the power supply board I have designated Q101. The part no. as written on the device is "C3311". This appears to be really a "2SC3311" transistor. There is an equivelent replacement made by NTE Electronics Inc. labeled "NTE2361". Unfortunately, I have so far been unable to source this component here in Australia so I can't test this theory. The US branch of RS Electronics stocks the NTE device and a few other places do as well.

So, if you have this component on your power supply board and if you can get a hold of a spare (and known working) one of these, you might have a shot at repairing the power supply.

Bear in mind that there are a number of different power supply designs, so it is possible that your problems stem from a different cause. All the tests I have done are on an Australian model (Euro) MK80200A-03 Saturn. The power supply for the MK80200A-50 is of a completely different design (and does not include this component), though it is still compatible with the -03 models. It may be just a lot simpler to find a working power supply and do a switch. Finding out just what is wrong is much more fun though.
 

mal

Member
Originally posted by Curtis@Feb. 09 2003, 9:17 pm

Finding out just what is wrong is much more fun though.

Hell yeah!

That's why I plugged away at modboard 'research' for so long.
 
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