Sega Saturn powers itself off

Just to add something. I was modding an exact same model machine today, and with the modchip it produced a lot of noise for cd-audio. I tried taking +5v from different sources closer to the PSU input (that FUSE point next to it is the closest, most easily accessible one), this alleviated the problem a little but there was still some noise. Without the modchip I couldn't really hear any noise.

Since changing the +5v source made a difference, I decided to swap out the power supply with a spare... and the problem went away. The bad power supply was the exact same VOLTEK model.

Seems those units are more prone to getting faulty than the FD ones, which is odd since this is the opposite of the later power supplies, where the FD ones are less reliable.

 

What do you mean with "noise". Like audio noise from your speakers or noise coming from the psu?
Which modchip did you use?
Always take the 5V from the mainboard pins, not from anywhere on the psu.
Have you measured hte voltage on the mainboard pins?
Maybe you must tweak the pot on the psu to get proper voltages.
I adjusted them too!
As far as I know, any noise is coming from unfiltered voltages, so there must be a cap thats bad.
I swapped out all caps on the psu I repaired too.

 

Noise as in white noise, as in the cd audio stream got corrupted. I guess I could measure the power supply pins but it doesn't really matter now, I had a spare that has no faults.

 

@ Druid II
I think the modchip is the source of the noise and when you put it behind the caps to get 5V the noise is a little less, cause the 5V get filtered till they get to the mainboard, so that reduces the noise. (sorry my english is not so good that i can explain it in professional)

@ retro
Do they have the correct messures and contact spacing as the originals ?

 

I also concluded that the modchip is the source of the noise as with it removed there were no noise. It passes through the CDDA data stream by the way, but taps the CDDA serial clock, so not getting a clean +5v would certainly impair that part. It was faster to swap the power supply though. Maybe that power supply would also benefit from recapping, but as it is the exact same type power supply as yours, so I imagine the PWM switch you replaced is on deaths door on this one as well.

 

And now the final question, is this cap low ESR ?
I found a lot caps, but only this one i got has low ESR

 

DragoonC, just wanted to thank you for this - my Saturn has issues with the power supply overheating and this might do the trick!

 

ok i had the same faulty the other week replace the top202yai fixed turning its self off its a transistor.

 

@ MangledLeg

Let me know if it helped.


I did not know that so much people have this problem and no one ever tried replacing this component :/

 

Replacing mosfets is pretty common when repairing things like this.

Never had the issue with a saturn myself though

 

The only Mosfet I replaced before on consoles, was one for the fan in a xbox 360.

 

The fact its on a console doesnt really make any difference - its a power supply, could be for console, could be for a TV.

Its good you have found what seems to be a common issue, but MOSFETs going is quite common. But now everyone having the symptoms is good

 

The only place I looked up were the local placed electronic distributors in germany ( they had none) and then ebay china.

 

Thank you for this thread. Just got a Saturn out of storage only to have it do the same thing! Don't have time to open it tonight but it could be the same thing.. Will investigate in the morning.

 

Thank you so much for following through on this and posting your results! Saved me a pile if debugging time! <3

 

A few people here mentioned switching the soldered in fuse with a fuse holder? In swapping my TOPxxx I shorted a connection and blew my fuse because I'm the worst. I figured I might as well replace the fuse with a fuse holder while I'm at it. Can someone post a link to a fuseholder that fits the MK-80000A psu board?