GDEMU SD Extender Repair

[HandsOnRepair]

What's good everyone? I've been a huge Dreamcast fan since it's released and is my favorite system of all time.

Recently my DC laser decided to finally fully stop reading discs. I recently ordered a DCEMU from Bitfunx. Along with it I ordered this and came with the SD card extender.

After having everything together I noticed it wasn't booting the GDMenu. I removed the SD card extender and inserted the SD card directly into the GDEMU and booted perfectly fine!

At this point I knew it was an issue the the SD extender. I tested continuity on each contact on the PCB to the SD card that plugs into the GDEMU in case there was a break somewhere. Had continuity on everything.

With an exacto knife, I removed the heat shrink tubing from the PCB. I was presented with a resistor (R1) and a tantalum capacitor (C2).

Using my DMM I tested the resistor and tested fine. Looking up the capacitor code, it should be 1µF. I tested it for a short and it tested good. Using my hot air station, I removed the cap and tested the capacitance. It was only .28nF! So it wasn't shorted, but the capacitance wasn't even close to what it should be.

I replaced it with a 1µF ceramic capacitor 0805 package. It could have taken a 1206, but 0805 was the largest I had on hand. Note: Ideally, you should replace it with a tantalum capacitor of the same value and size. I'll report back if I have any issues down the road using a standard non-polarized ceramic capacitor.

Hooked everything back up and I was presented with the GDMenu! I've been using it a few hours without a single issue so far.

If you have an issue with your SD extender, make sure to check the soldering on the flex cable and the capacitor mentioned. Hopefully this helps someone out there and keep dreaming!

[redjeff76]

Interesting. But I had that same issue, but realized that the mount kit was making it so the SD Extender was too crunched or bent up when everything was hooked together properly. I wasn't able to get my Dreamcast to load my GDEMU menu (just the DC Bios). So I took it all apart and repositioned the SD extender ribbon so it wasn't so folded to bunched up. I put everything back together and started up the Dreamcast and ta-da, there was the GDEMU menu and everything has been working great ever since.

So your problem could be unique and you figured it out. Or your problem could have been similar to mine. I dunno...if people are having a similar issue, perhaps try both "fixes"?

[HandsOnRepair]

Very possible! The flex cable in mine is also a very tight fit and mention to check it in my original post as well. I did end up reflowing the contacts on the PCB where the flex cable meets the SD extender PCB after the repair while I had it out. Even though that wasn't my specific issue, I wanted a little extra solder there. More of a peace of mind thing. I folded mine so that it was somewhat under the frame and held in place.

I didn't happen to grab a picture of me testing the cap, but I do still have it in case someone wants me to snap a pic.

[MoeFoh]

My original extender cable was 18 inches long. Ridiculous! I ordered a 6 inch replacement that has worked fine. I didn't realize there are components on the extender cable - I thought is was straight through.

[HandsOnRepair]

18" is pretty ridiculous! You can just cut it to size and melt back some of the flex cable coating exposing the metal. They are just thin strips of metal that you can solder directly to the PCB solder pads. That can always be an option for you as well.

To be honest, I wasn't expecting components either. I guess it would make sense due to the length of the flex cable. It would have to store enough charge for it to work properly.