sega cdx issue/ need advice or parts

the isproplyne and swabs do come in handy, the top board looks untouched (the last 2 pic of that board is after a clean, as well as the bottom)
haven had a chance yet to test it and wont for a week. traces look good on both boards but the pads the rusty legs are on would be a lost cause , having said that you would be hard pressed to find a board that has been in worse condition to get parts from, plus im getting the power board off this one and what ever i need for the other board (bios) so i wont be reflowing this board, not that i know how.

any links to resources or schematics would be appreciated, still got to get around to working out if it was the bios that needed replacing on that other board.

if i dont need it to get that other board going that 315 5619 and screw is all yours! i may have to trade it to you for your skills and have you have a look at that board, im interested in getting onto this level but i was thinking starting off on something like a NES or SNES, there is being keen and then there is jumping in the deep end of the shark pool. atm im just doing recapping, laser swaps and rgb mods.
you know, tutorialized monkey see, monkey do kind of stuff.

 

wow, great job cleaning that board up! Those ASICS do look pretty nasty heh. I'm wondering how bad the system was damaged when this guy turned it on - I'd be surprised if they booted. However, if you could pull the Genesis ASIC from a model 2 (they are about $10 these days) and put it on this board (I've done harder jobs before, but you *would* need a reflow station), you might be in luck. Likewise, I think the Sega CD model 2 has that other ASIC. I would be weary of booting it with those current chips, for fear of damaging other parts. It is possible the Sega CD board was damaged if it was powered on too - since the Sega CD ASIC communicates with it through many pins. Let's just say I wouldn't go swapping boards with a working Genesis CDX PCB unless you are feeling *very* brave.

Awesome, that would be great. that chip is only used for audio - it mixes the Genesis audio output with the Sega CD audio DAC. It is completely separate from the CD board that you have there, if that is what you mean. It's also purely an analog chi from what I recall, so even if removed you should be able to have your system boot fine.

I think it is very wise to consider hacking and repairing cheaper systems and working your way up. I wish I had done this myself, but instead destroyed (I'm ashamed to say) many CDX, Sega Saturns, and even *gasp* a Laseractive! I had a pile I called my "electronics graveyard" - this was all circa 2003-2004 when I started soldering. Better to work on an NES first

I'd be happy to look at this board for ya. If you wanted some hours of work done though maybe we could work out a trade for a cheap game or two. We can chat over PM when you are free next week.

-Segasonicfan

 

Hope the OP of this thread doesn't mind me posting about my Multi-Mega / CDX Issue. Its an Incredibly strange one to say the least!

So here is what happened. I was playing Micky Mania (Mega CD version) when suddenly during the game the background graphics completely glitched up to hell! I then reset the Console and noticed the graphics on the Mega CD BIOS screen were also glitched up but the Jingle still played. Then I switched the Console off and back on again and got a Black screen. Tried a Cart and got a black screen.... was very upset and almost cried. Put it away for a week or 2.

Then decided to fire it back up again and it worked ok with a Cart (Sonic 3) for a while. Then started playing Streets Of Rage 3 and again it glitched up the graphics part way through playing the game and then crashed. After that again black screen when trying to fire it back up shortly afterwards. What on earth could be causing it? Capacitors perhaps? Any advice you guys can give is much appreciated. The Multi-Mega has never been opened up and looks in decent shape on the outside.

 

Well, your first problem was you were playing Mickey Mania on Mega CD ;P The Genesis version is far better with no load times and better boss music! Great game, one of my favorites.

yeah, sounds like capacitors for sure. and it is probably going to be on your bottom PCB (with the Genesis cart slot). There's only like 5 caps to change. I'd start with the one next to your Sega ASIC on the right under the cart slot - that has the VDP which is crashing on you.

-Segasonicfan

 

UPDATE:
So Dylbob42 sent me these broken units to work on and I successfully repaired the BIOS issue! Turns out it was corrosion of the Sega CD ASIC near the cart slot (pic attached). A single trace was corroded through and needed a tiny wire jumped to another part of the board. Boots and plays perfect now. I find these BIOS issues are pretty much always communication issues and never the BIOS chip itself.

I also went ahead and tried to repair the rusted unit, mostly for the LOLs (and cause I'm crazy like that). I got a free Genesis 2 with a 315-5660-02 which appears to be the same pinout as the 315-5660. So I reflowed it onto the board, hah. I had to hand solder many of the pins though and a few had to be jumped from the rusted Sega CD ASIC. The board is in surprisingly good shape.
Alas, it won't boot BUT I do get the startup flicker of the screen when applying power. No strange noises or anything. I think the board mostly works but for dead RAM or CPU possibly. It was neat to work on it and now I know most of the analog parts are good (i.e. no direct power shorts anyway).

Attached are also some pics of the pots in STOCK position of a working laser because people keep asking me for this. I posted the measurements on Sega 16 a while back.

-Segasonicfan

 

Wow. Thanks for sharing this update, segasonicfan! Nice work!

 

So it's been a long time since these original posts, but I keep all my CDX / sega parts in a special location for when I have the skills built up to do necessary repairs. Since I've been getting especially good at Sega CD repairs lately I decided to give this one another go. And success! I actually saved a working motherboard combo next up was to tackle the horrific rust:



Special thanks to dylbob42 for giving me a great deal and letting me save this poor beast. Progress is going well, and all I have left is:

1) source the missing cartridge insert plastic that holds the power motherboard (hopefully dylbob42 finds this in his stash)
2) source original case screws
3) fix the open lid button (the spring in it has been badly rusted and it's been a real pain to get working).

I did manage to fix the rust in the CD lid hinge which was no easy task. I also have most of the rust cleaned off the plastic pretty well. I'll need to use some turtlewax for other damage to the plastic case still.

This ones a real job for sure! but segasonicfan doesn't give up

 

holy shit dude!

pretty impressive stuff!

 

Heh, yea it might look easy, but it took me some hours. I actually used a bunch of Q-tips another rust remover as well. Labor of love, as they say.

Btw I figured out what that dust cover you sent me goes to- it's for a Genesis model 1! lmk if you ever come across the CDX one in your magical parts bins one of these days.