Sega CD Model 1

[ryanstein]

Hey all, I picked up a model 1 Sega CD off eBay thinking the entire issue would be the fuse. But alas, after jumping it, it still didn't work. It turned out that it looks like somebody plugged in a NES adapter into it, unfortunately, obviously blowing it since it's an AC adapter. After digging out the power board, I found out it looked like this board: here. I removed and bridged TR4 transistor, as well, but still no power other than the occasional double light blink. I'm guessing I need to do something with the caps on the bottom: C22 and C23, though from what I'm reading, only 50% of people say that they are actually necessary to achieving power. I would try and run jumper wires to bypass the possibly corroded traces, but I'm not sure where to run them. Does anybody have ideas of what else to try? (Other than possibly trying to pick up a new power board...)

[PyramidHeadcrab]

The first thing I'd do is get rid of all that excess solder and melted gunk - get a solder sucker if you don't have one. It'll give you a better idea of the damage. I'd also replace any wires connected to that melted part, as those may be screwed up as well - if not now, then down the road. As for specifics on what to fix, it's hard to say until you cxlean it up a bit.

[KalessinDB]

Does the Sega CD have a 7805 voltage regulator? When I made the mistake of plugging in an NES adapter to my AV Famicom, that's the part that blew, and my friend who's good with a soldering iron was like "Yep, that's about a 25 cent part and 5 minutes worth of work" and did it for me.

Just a thought.

[Hobie-wan]

Sega wouldn't have put the components there if they weren't a good idea. Companies love saving components that are 5 for a penny if they can. Even that cheap, if there are 20 in some thing they make and that's 4 cents, if they make 400000 of the item that's still $10000 they saved plus the labor and whatnot.

[ryanstein]

Unfortunately, it doesn't have the voltage regulator, which creates these problems and blows these components. I had to remove the transistor since it blew because of it. I think I might follow that suggestion and remove those caps. (Though I can't quite see where the traces are supposed to connect. Anybody have a picture of a functional board that I can analyze?) However, as I understand it, they're just part of the power inductor and even if they're not functional, I should still have power. I just wouldn't have any power noise filtration. Is that correct?

[ryanstein]

So I ended up finding another model 1 Sega CD with the standard fuse problem. Unfortunately, the guy who owned it clearly had no soldering experience and even tried fixing it without removing the power board. He ended up seemingly destroying the solder locations as I can't get a new fuse to work in that spot. Does anybody know of any alternate points I can connect a fuse to?

[Hobie-wan]

You'd just follow the lines to another junction or the leg of the next component. I don't mean to be mean, but the fact you were trying to run the other by just bypassing blown components and don't know to just follow the lines makes me worry about the survivability chances of this one too.

[ryanstein]

You'd just follow the lines to another junction or the leg of the next component. I don't mean to be mean, but the fact you were trying to run the other by just bypassing blown components and don't know to just follow the lines makes me worry about the survivability chances of this one too.

Obviously I can follow traces. I meant if there was another spot on the board that would work down the line. The blown components I was talking about were nothing important - I was following diagrams posted on DigitPress. The transistor, for example, is what switches the unit off when you switch off the power to the Genesis. If it blew, no harm in bridging it to prevent it from turning the unit on before I replace the component.

[ryanstein]

Boom! Fully working Sega CD!

Now to celebrate with some Willy Beamish, Sonic CD, and Sonic Megamix!

2014-03-22 11.12.26 compressed.jpg (124.08 KiB) Viewed 2007 times

2014-03-22 14.08.34 compressed.jpg (86.21 KiB) Viewed 2007 times

[Hobie-wan]

Yay back to life.