Dreamcast power supply repairs

Say that a some idiot (totally not me) had accidentally plugged a japanese dreamcast into the UK mains and blown the power supply up, which components are likely to have snuffed it? Aside from the giant capacitor which was billowing smoke all over the place. That has been replaced and it's still broken.

 

You have two options

1 Find and replace the broken components (Normally the fuse+Cap or two and possible a Thirister on the primary side)
2 Replace the power supply with a 220V one, gamedoctorhk has them for $9 http://gamedoctorhk.com/index.php?main_page=product_info&cPath=72_2_20_117&products_id=1414

Honestly I highly recommend 1 , it will work out a lot cheaper but cost you a bit of time and some soldering.

 

Fuse most likely, if you got a flash it'd be the fuse.

 

A fuse was the first thing I looked for, is it that black thing on the right side of the power switch plug?

 

Its the black round piece of plastic just after the power jack, I wouldn't recommend just replacing it and hoping for the best, at least give the board a proper once over visually and with your multimeter.

Edit: If you saw a flash and heard a bang look for any components that might have popped.

 

Allso check the wires that goes to the power switch theres some components on there aswell if memory servers.

 

I've been going over it on and off for the last few months haha this happened a fair ol' while ago. The power switch works with a european power board so the capacitor on those wires is fine and dandy. Visually it looks pretty much intact, the only thing which seemed to be damaged was the big capacitor (it made a bang, leaked shit everywhere and made masses of smoke so yeah that had definately popped ) which I replaced at the time. Surprised it took me so long to work out that the cylindrical thing was the fuse haha guess it just wasn't what I was expecting.
Testing the fuse, it has indeed blown, is there anything else i should check witht he multimeter before I before I replace the fuse and see what happens?

 

So you already replaced the big capacitor

The power switch is indeed universal, but if I remember it had two caps on it or something like that, you can check the continuity of the ceramic caps in the area and see if any of them are bridged (they fail sometimes and if they do will bridge) but generally if they fail there will be some physical damage to them aswell.

You can replace the fuse with a glass fuse of the same value.

If all of that is fine, it should be okay to move on and replace the fuse, and test it CAREFULLY.

What I do if I have doubts, is connect it to step down transformer, then plug the transformer into a unplugged extension lead, switch the power switch to "ON" on the console(with the lead still plugged out) and put the console somewhere safe, then plug the lead into a wall socket and quickly turn it on from the wall socket.

PS there might be other things on a dreamcast that might be wrong, but the above is what I do to other consoles when connected to 220V

 

no the dreamcast and the power swich definately work, as i said previously I hooked it up to a 220v power supply after this happened and everything was still running nicely

 

Good then just check the other caps on the board...

 

so what am I expecting to see on a failed capacitor?

 

cracks, and black spots

 

I know how to spot physical capacitor damage they all look fine I meant using a multimeter what am i looking for?

 

a dead short between the two points on the cap, just set it to continuity and see if any of the caps are shorted out.

 

Not sure that I want to admit this because it's going to make me look like a massive retard
The root of all my problems are simply that i soldered the big fat cap replacement on the wrong way round, i used the PAL power supply board as a guide (because the original japanese fat cap had properly melted so it was difficult to tell) and they face the opposite direction on that.
Seems like I've been making a lot of these stupid msitakes in the last year, maybe university stress is getting to me more than I realise...
I replaced the fuse with a 1.5A picofuse I had lying around (the original was 1.6), turned the capacitor around and just like that we have life
Thank you for being so patient with me and helping me work this out haha. I'm sure I will be able to use this process again the next time I plug the bloody thing directly into the mains...

 

Good to hear you got it sorted

Just as a side note, be very careful of fitting electrolytic capacitors the wrong way round, they tend to explode, violently, if there fitted the wrong way round that being said glad it didnt in your case.

PS the silk screen on the board will normally have one half filled with stripes, this side indicates the negative side of the cap

 

Yeah, when I realised what I had done wrong I was incredibly irritated with myself and at the same time so very relieved that there was no explosion
I worked it out after looking closely at the board and seeing a little "+" sign near where I had installed the negative side of the capacitor, I don't know what the hell I was doing all those months ago when I replaced it, I'm usually much more careful than that...

 

No problem, no need to get yourself down, you got it working and thats all that matters

Ive done worse things