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/vr/ - Retro Games

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File: 2.40 MB, 1920x1900, sega-cd-motherboard.jpg [View same] [iqdb] [saucenao] [google]
1743189 No.1743189[DELETED]  [Reply] [Original]

Holy shit, look at this crazy Sega CD motherboard.

What the hell are all those chips for?

>> No.1743192


>> No.1743195

Magic smoke containers.
in all seriousness though, there's cd controllers, cpu, dac and all sorts of other stuff there.

>> No.1743203

No idea without a circuit diagram.

You can look up individual chips by the model numbers for some novelty.

The Sony chip in the center appears to be a CPU or microcontroller of some sort. The one above it is a DSP, probably for reading the data from the CDROM.

The Toshiba chips are RAM.

The Sharp chips appear to be some other type of ram. The datasheets didn't make the intent clear. Perhaps firmware?

Lots of fun to be had by chucking these chip names into your favorite search engine.

>> No.1743204

Each chip corresponds with an FMV scene in Night Trap.

>> No.1743229
File: 483 KB, 141x141, thumbsup.gif [View same] [iqdb] [saucenao] [google]

True story

>> No.1743237

I don't know, but the Sega CD is a fucking nightmare to try to troubleshoot.
I got my Sega CD untested with a dead power supply. I got a replacement power supply and the system still wouldn't turn on. I disassembled the system and a quick check with the volt meter determined that one of the fuses was bad. I replaced the fuse and reassembled everything. I again tried to turn the system on with no success, but this time the power supply got really hot and within a minute of being plugged in it caught fire and started billowing smoke out of the the gap around the cable lead. After yanking everything apart and throwing the burning power supply out the back door, I again dissembled the Sega CD only to find that my replacement fuse had not only blown, but had literally melted.
The best I can figure is that there's something wrong on the motherboard that's killing the power supplies and causing the fuses to blow. I couldn't find any bad caps on the motherboard, and I'm afraid to try to try and troubleshoot it further for fear that the system might explode, that, and the circuitry is so intricate I have no idea where to start

>> No.1743240


What the fuck is that blue thing? I've never seen anything like that on a motherboard anywhere.

>> No.1743252

CXP seems to be a 4bit micro controller, CDX seems to be the cd controller. The pair of toshiba chips are 1m bit ram chips, and the sharp chips are 256k bit ram chips. One of the sanyos looks like a 16 bit DAC, the other one seems to be part of the cd interface. The Moto 68k is the main CPU for the system. i think the panisonic is also ram (or maybe rom) but im having a hell of a time tracking it down. still missing about 3.5 mbit of ram, maybe its on the other side of the board.

>> No.1743253

CMOS battery, used to keep the system clock running and save BIOS settings almost all modern motherboards have them
In the case of the Sega CD it might also be used to hold settings and save data in SRAM

>> No.1743282

Well, that's one of the more dramatic broken console stories I've heard lately.

>> No.1743291

I've got a dead model 2 Sega CD. Are there any places online that can fix it? I'm in Canada.

>> No.1743321

look at it this way, you got yourself a cool looking paper weight now

>> No.1743418

you probably just have to replace one fuse you could just bridge it with a wire and leave the fuse in place to see if that is the problem.

>> No.1743506

It wasn't actually dead when I found it, though it wouldn't read CDs. Somehow I thought that trying another power adapter would do the trick. That's what killed it. It's been sitting in a box collecting dust since then, and I only remembered it recently.

>> No.1743543

that could very well be a blown fuse then

>> No.1744578

CXD2500BQ is CD-DSP (convert analog CD signal to digital serial data)
CXP5084 is CDD Processor (process BIOS commands and talks with DSP)
Sanyo LC7883 is CD audio DAC (convert digital audio to analog sound)
Sanyo LC89515 is CD Controller (error-correction and decoding of CD serial data)
MC68HC000 is 68000 CPU
Sega 315-576A is PCM audio chip
Sega 315-5632 is general purpose ASIC (Sega CD registers, GPU, etc)
MPR-15674 chip is Mask PROM that contains BIOS ROM
other chips (Sharp, Panasonic, Toshiba & Fujitsu) are various RAM chips

>> No.1746096

um that sounds like a short to ground
you may want to check various traces for continuity and see what the issue is

>> No.1748130

Thanks for the tip.
One of the solder joints on my replacement fuse was contacting the bottom heat shield, a bit of electrical tape and a new power supply fixed it right up.
but now it won't recognize discs

>> No.1748146

Most of them are just anti piracy measures. Try to back and they release mustard race gas.

>> No.1748150