Broken Sega Saturn power supply

I have this Saturn model 2 that stoped working after falling from my bed, it was on my bag with some cables and cable and fell from my bed on the floor.

After i tried to fire it up on a friends house, the system led light on but nothing would happen, and after some time not even light up the led anymore.

I already replaced a burst capacitor some time ago, but it didnt gave me any trouble since.

After some tests its a problem on the power board indeed, when i turn it on i hear nothing, but when i switch it of i hear a fainting whining coming..

Anyone know what i need to replace? I think it maybe the transformer on it, but not sure.

If it to much trouble im thinking on scrap the psu board and put a regulated power supply on its place

 

Tests? What tests? I'd encourage you to be specific. Did you get the system to work again after replacing the power board? This is what this statement suggests to me.

Where does the faint whine come from specifically?

I'm by no means an expert on Saturn recovery, indeed there are a few others on here who know more than me but I'd say that this doesn't seem like a PSU related issue to me as it sounds like there was power being fed to the board initially but something else had blown.

Are you able to get some Hi-Res images uploaded to imgur.com so that we can have a look at the main board and PSU and whatever else you think is relevant?

Just trying to help, the more info you can provide no matter how small the bigger the picture is on this end.

 

Yeah, i replace the power board with the one on my other Saturn and it works fine, even put this bad on on the good Saturn. and it wouldnt power on, so im sure its a problem with the psu.

The fainting whine sound come from the psu board, but i cant quite tell from which place.

EDIT: photos of the PSU Board

 

I'd suggest replacing the entire PSU in that case as you've pinpointed the problem. I know you're looking for a solution to fix the PSU board itself with individual components and you probably will do depending on your level of obsession with the problem.

However I'd suggest this problem will only be solved with hours and hours of time spent with a multimeter checking each track of the hundreds which make up the PSU.

I'm sure I've seen people here selling saturn PSUs, also I've even heard they are compatible with dreamcast PSUs (beware of the possible myth on that statement!).

My first port of call would be:
http://segasaturngroup.proboards.com/index.cgi

Make yourself known there, also post a thread in the WTB (want to buy) market place sub forum here and you should definitely find a working PSU for a very reasonable price. Over on the board I linked to above they should have spares going as they have a 'if it's not working and you're gonna throw it out, we'll buy it' policy.

Though if you want to trouble shoot the PSU itself then carry on :nod: by all means...

Again, just trying to help.

 

i intend on replacing the faulty components on the psu itself, but if its not worth the time/price of the components, i will buy another one or replace by a similar power supply, as i see it only takes the 100ac and convert to 5dc

A dreamcast psu would be a good option if its really compatible, i have a couple good ones here.

 

Wow it's like a carbon copy of my broken dreamcast power board post
http://www.assemblergames.com/forums/showthread.php?t=35694
Someone said rectifier diodes, someone else said capacitors, and someone else said voltage control. Gave up after replacing a capacitor and bought a new board. But if you get this worked out, there may be hope for my broken one yet.

 

x

 

The fuse its ok, i already measure it with the multimeter. What i may replace its the diode bridge or a couple transistors.

If its the transformer i can say good bye, its worth buying a new psu board than a new transformer.

 

Yes repairing PSU's often involves some testing on the Live side of the PSU, which I do not recommend if you're not well-versed with working with live mains and rectified high voltage DC. Even the heatsinks can be lethal if touched!

A qualified engineer would first re-solder everything just to rule-out dry joints, then check all the secondary voltages (5v/ 12v etc), on the output connector. If one or more is missing then this can be traced through the components for that particular output, or 'rail'.
If the PSU shows proper voltages but then fails under load conditions, then this can be down to a bad capacitor, protection Zener diode or rectifier in the secondary.

If there are no voltages reaching the secondary, a check on the DC output of the rectifier would normally be a good place to start (should be around 200v DC there - roughly the same as what the big reservoir capacitor is rated at. Naturally on a PSU designed for 230v AC this'll be a lot higher (around 350v).

Usually a shot mains rectifier will take out the fuse, as will a bad filter capacitor which is marked C1 on the PCB (big black rectangular thing).

Anyway, ignore my waffle and save yourself some time and expense and get another PSU from someplace! pub:

 

That power supply is a piece of trash ! :flamethrower: it ...

Actually it's a dual voltage PSU made by Tec Toy for Brazil.

Made with sub par low quality parts and very poor printed circuit board it burns out quite fast just from being used. Try to find an original SEGA power supply to replace it. :thumbsup:

 

If you don't know how to fault find on a PSU, put it to one side and replace it. They're dangerous things, and it doesn't sound like you know the theory of how one works.

Brush up on your electronics theory, particularly PSU fundamentals. I seem to recall there being a book in the Babani series on PSU design. And general fault finding practice.

Once you're more experienced, you'll realize why you can't say "it's making a noise - what should I replace?" - that's akin to asking a mechanic what's causing the unusual sound eminating from somewhere within your car!

I know I've already said it, but you're working on a live circuit with mains voltage here - for God's sake don't proceed unless you know exactly what you are doing and take the correct precautions!

 

Dont you have the primary side and then the secondary side of the power supply?

Anyway, in this case just replace it with another

 

I know they are shit, but i just wanted to repair this one, as its a reserve saturn, my main saturn its a original japanese model.

I have some basic knowledge of power supplys, like how they rectify the ac to dc using a diode bridge, and filter with capacitor, etc. But that dont take a point like i was asking theres a sound in my car, how i fix it XP

its a small part of the console, and i thought it would be a commom problem for people that had already fixed it, because making a sound like that when i power off means its discharging something.

Its not like i would die with a power supply either trying to repair with it unpluged XP



i will eventualy replace it with a new one, thanks everyone

 

Retro's advice is so well given, I don't think I would be able to write an warning as good as his.

Yes, steer away from messing around with it. Even with electronics knowledge I had been zapped a few times with charged capacitors or had them blow up on my face while servicing such devices. :shrug:

 

I'd do what another guy wrote and resolder the components, starting with the heaviest things (transformer is a prime suspect). It doesn't really require a lot of force to break a solder joint and a 30cm drop ends up in a lot of G's when deaccelerating.

 

What about fitting a Switching Board? I know that it would be different than the stock one, but for sure it will be more powerful and fresher than an used replacement.

If the Saturn showed problems after falling, I'd suspect cracked solder joints and replace the capacitors only. You could also reflow the legs under the regulators.


Cheers,
Oge

 

I have one that winnes its the transforma and i dont know what we could replace that with??? any help would be cool.