Sega Saturn Problem

So recently I decided to play some Saturn (used to work fine months ago) and it keeps freezing. This freezing happens at random times. Sometimes I get it to boot the game, play some seconds or minutes (if I'm lucky) until the whole thing freezes (the reset button wont even work). Sometimes the CD loads but arrives at a black screen. Sometimes it freezes on the menu of the game. I tried several games (both originals and backups), the problem is on every game. The most confusing thing, often it also freezes while booting the console, at the saturn logo, without any CD placed.
It's probably the laser that's giving it's last breaths but the fact that it sometimes freezes at startup really threw me off. So, do I have a dead saturn or is there something else wrong?

Thanks for any help!

 

I believe as time goes on this is pretty common with Saturns - it was working, you put it away for a few months, and now it wont work. I don't know the Saturn well so maybe someone else will have some suggestions, but a few of my SEGA friends have had the same thing.

 

Let me guess, it's a Model 1 Saturn? Maybe PAL?

 

It's a PAL console, model 2

 

If it's a VA5, there's a good chance it's your power supply. Could you take the top off and post a picture?

 

I'm sorry for the low quality but I don't have any other means to take a picture at the moment. Hope this helps.
http://prnt.sc/bys00n
http://prnt.sc/bys0do
http://prnt.sc/byrzlv

 

Usually this behavior comes with an aging PWM switcher and low quality caps which causes a ripple effect on your power rails. I would rule the laser out at this point, since the freezing also happens in the startup section. You could do two things, one, change the power supply (if you have access to a second 5 pin saturn PSU), second, change the PWM switcher and the caps in one go. The PWM power switch is the black thingy mounted on a steel plate, facing the 400V 22µf capacitor.

The PWM switcher is a TO-220 package, in other Saturn PSU's it's a TOP202YAI, but I think in your model it's a different component (it's printed on).

 

A friend of mine has a model 2 with a dead laser, but the system seems to boot fine, I could ask if he would sell it, and try to cannibalize parts. Would it be a simple matter of unplugging and unscrewing or would it require some solder work? I ask because I can't work a soldering iron to save my own life and have 0 knowledge with electronic components.

 

I think your Saturn looks like a VA9ish revision, but I'm not sure. If your buddy has the same board revision as yours, it will fit even if it looks different. Model 1 PSUs wont fit physically afaik, but if the pin connector from a model 2 is in the exact same spot as yours, it will fit regardless of the revision. Does that make sense?

 

Yeah thanks! I will take it to his house and try it out. I really appreciate the help!

 

x

 

The later revisions have a similar but simplified PSU design, they do however, use the same PWM switching method, the switch itself is just a different brand. Those won't fail as often as the TOP202, but they do fail with age. Since he has no Oscilloscope to properly check the outputs, it's still a shot in the dark but easier to verify as recapping the whole MB. But yes, it could also be the caps on the MB. Did you've recapped your board? May I ask which ones checked out faulty? Just in case I run into a similar case down the road

 

x

 

i saw a Youtube recently and the person who made it mentioned he had freezing if no battery was in the Saturn , you want to check if your battery is in the Saturn and has enough power to do its job.

 

Do you mean the 5746? I've received a package with three dead Saturn's today, I got 2 of them fixed, but the third one has a video ouput issue, just a black screen, no sound, no cd. I've hooked it up to the bench power supply, same result. I've replaced all the caps around the 5746 plus the one on the 5963 (checked the old ones with an ESR meter, all checked out fine) , but still no luck.

Any suggestions? I don't want to shotgun the whole board. It's a VA5 PAL.

 

compare current draw between good mobo and faulty one (if thjey are known to pull same current if different revisions). Excessive current draw would indicate a short.. Somewhere to start...

do you have an oscilloscope and a H field probe? That could help weed out bad processor

Check the VCD and memory card slot for shorts

Look over the PCB closely for any odd looking traces

 

x

 

If I turn it on, the scart detect pin goes high and the power led lights up, aside from those two, no signs of life at all. I've gone as far as testing all the caps out of circuit, but all of them checked out. The smd 7805 on the board also works, so there's a good chance that one of the asics or srams has bitten the dust and that would mean hours of tracking the fault down and still having no suitable replacement at hand. I don't think it's worth the effort, sadly.

One thing, if I cut the power, the led doesn't go out instantly as usual, it kinda flashes 1-2 times and then goes out. No idea why, but I found that odd.

 

Druid, do you still have those dead boards at hand? As a last ditch effort, I've decided to selectively heat up and freeze the IC's which are the first ones in boot order, which means SH2-Master and -Slave plus RAM IC 3/4. Three out of three came back to life after that.

This may be fun to investigate further.

Update: It's the SDRAM, either IC3 or IC4 on all 3 dead boards, not the CPU's.

 

try cleaning the pins that connect the psu to the mainboard and retention the connectors on the psu itself, was a common issue with dreamcasts aswel, maybe thats whats happening here.