Sega CD systems repair thread

[Bizous]

Yikes, you're going to need to do a full recap and other work in addition to that part. That is simply a resistor array, very easy to replace. Its just 4x 4K7 resistors.

Thank you for your reply Segasonicfan .

I ordered all the capacitors to replace them. ( I am waiting for the order )

Met I can not find this resistance ALPS 472.
Can you show me which ones I have to buy to replace it .

Sorry for my English

[segasonicfan]

Thank you for your reply Segasonicfan .

I ordered all the capacitors to replace them. ( I am waiting for the order )

Met I can not find this resistance ALPS 472.
Can you show me which ones I have to buy to replace it .

Sorry for my English

Hi, no problem. I assure you my French is much worse than your English (and your English is quite good by the way!)
that's good that you ordered the capacitors. You will also need to clean the board thoroughly with isopropyl alcohol.
I can look up the part for you at a distributor, but I don't know which one you would use in France. here in the US we tend to use Mouser or Digikey. I think they would ship internationally but I'm not sure.

can you take a measurement of the dimensions of the part (L x W?) that will help too.

[Bizous]

Hi, no problem. I assure you my French is much worse than your English (and your English is quite good by the way!)
that's good that you ordered the capacitors. You will also need to clean the board thoroughly with isopropyl alcohol.
I can look up the part for you at a distributor, but I don't know which one you would use in France. here in the US we tend to use Mouser or Digikey. I think they would ship internationally but I'm not sure.

can you take a measurement of the dimensions of the part (L x W?) that will help too.

lol, thank you very much
I train in English looking at the series in Original Version,
Do you want to watch French series to learn French ?

The size of the ALPS 472 parts
Length : 6,5 Millimeter
Width : 3,5 Millimeter
Height : 0,5 Millimeter

Thank you for your help

[segasonicfan]

the part is actually surprisingly difficult to source. most likely cuz it uses a larger package type than what's manufactured today. something like this would work well though if you just use half of the resistors, because it has 8 instead of 4:

https://www.mouser.com/ProductDetail...2qMorsAV5v0%3D

also, I took a look at the schematic and found the part that you're replacing. Its good to have for reference.:

Screenshot_20190322-203924.jpg

keep in mind, you're still going to have to replace all the capacitors, do a lot of cleaning with isopropyl alcohol and possibly fix traces as well.
you can see this video I made about how to do that with the Sega Game Gear, for a proper way to do capacitor replacement and cleaning:

https://m.youtube.com/watch?v=fbum0CE2T7o

[Bizous]

the part is actually surprisingly difficult to source. most likely cuz it uses a larger package type than what's manufactured today. something like this would work well though if you just use half of the resistors, because it has 8 instead of 4:

https://www.mouser.com/ProductDetail...2qMorsAV5v0%3D

also, I took a look at the schematic and found the part that you're replacing. Its good to have for reference.:

Screenshot_20190322-203924.jpg

keep in mind, you're still going to have to replace all the capacitors, do a lot of cleaning with isopropyl alcohol and possibly fix traces as well.
you can see this video I made about how to do that with the Sega Game Gear, for a proper way to do capacitor replacement and cleaning:

https://m.youtube.com/watch?v=fbum0CE2T7o

Thanks for your help Segasonicfan
As soon as I received my order, and start repairing it.
I will give you news.
Thanks again

[seat safety switch]

I recently repaired a CDX with similar symptoms. It looks like a VRAM issue. If you get to TMSS then your 68K and connections are likely fine. I vote that its your MSM54C864-10 (IC192) and / or shorted connection issues to it with the 315-5660. My CDX would load the sega logo and glitch out similarly. It was that chip, and a short to GND on the VRAM bus (a dead 315-5660 pin yuck).

Thanks for the reply. I was hoping it might be the VRAM because it's difficult to source a replacement 315-5660 VDP (all of my "for parts" Genesis 2 have an annoying habit of getting fixed).

How did you find the short to GND on the VRAM bus? I have a slightly corroded pin on the VDP from some kind of goo damage, but it's on the DMA pins and they are continuous with the 68K and not shorted with each other.

I did a quick continuity test from all the pins of the VRAM chip to GND but didn't find anything with the machine at rest.

The VDP is getting noticeably warmer to the touch than the other chips but I wouldn't call it "shorted hot."

[segasonicfan]

The VDP is getting noticeably warmer to the touch than the other chips but I wouldn't call it "shorted hot."

It is very risky to be powering on a damaged system like this. The longer you leave it on the more risk you run of more shorts and damage to the ICs.

You have a very tricky repair here. If theres no obvious VDP shorts than you have a Lot of testing to do. It's not something I could really troubleshoot online, but if you want to send it in maybe we can work something out. However, these kinds of repairs are difficult and extremely time-consuming (ie expensive).

Honestly, if you have any sort of day job I would recommend just selling this one for parts. I might be interested in buying it from you and try to repair it in my downtime. Ive had repairs like this take 10+ hours so its hard to just offer quick advice for it.

[vintagegamecrazy]

Does anyone know where I could find a replacement laser motor for a Sega CD model 2? It is the model with the sockets on the disc drive and not the ribbon cable. The motor is very noisy and has lots of friction when spinning.

[segasonicfan]

Does anyone know where I could find a replacement laser motor for a Sega CD model 2? It is the model with the sockets on the disc drive and not the ribbon cable. The motor is very noisy and has lots of friction when spinning.

I don't know off the top of my head, but posting a picture or model number (or both) would certainly be helpful in your quest.