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I decided to dust off my childhood Turbo Duo. One thing that happens with these things is the capacitors are poo poo and need to be replaced. I've replaced the caps and am having problems. This will be an ongoing thread as I keep working on it. I was able to play a few card games, (CD ROM Currently dead) once I was satisfied that it was working I walked away with it left on for an hour. When I came back the screen was just a massive glitch. After turning it off and on the screen on time is delayed, and there was only a white screen. The CD bios also no longer shows, so this is with or without a game in. I also re connected the CD drive just to see what would happen. I went over the board with my camera phone zoomed in, looking for debris or anything else. All looks good. I don't know what happened. https://www.youtube.com/watch?v=BMhmyHjG27A So there it is, acting dumb. Later I found something. I was able to smell the board burning and noticed that two vias were smoking. I could only see the one side of the vias as the other side was covered by the large chip, I assume it is the main CPU, but I don't know. I removed the IC and found this: The vias that were smoking are marked with red dots. They were passing the smoke that was from the burnt area between the two traces to the visible side of the board.  I cleaned the area with a scratch brush and some IPA:  I plugged the board in, turned the switch on and that area visibly lit on fire. Further cleaning shows that I can pick pieces of the PCB out:  I flipped the board over to the cap side, I marked with arrows to where the scorch mark is on the other side. I put dots on the vias were I originally saw the smoke. I measured resistance between the two leads of cap C501 and got around 300-350 ohms. I also removed the cap and measured the pads, same 300-350 ohms.  So I dug and dug, cleaning it out.   After this the short was no longer measured and I re flowed the chip back into place. I wasn't planning on making a thread, so I'll have more images from here on out as I didn't document everything.  Currently it turns on, but the sound is hosed and there is no CD BIOS, I only get a white screen if I don't have a game card in. The screen should show the CD BIOS when a card is not inserted. Either the chip is hosed or some logic still thinks a game card is inserted. If I use a Turbo Everdrive I can bypass this problem and attempt to run a CD game. The laser no longer goes crazy like in the top video since the short has been fixed. Next thing to do is replace the CD laser and change out some audio chips. Aeka 2.0 fucked around with this message at 21:34 on Feb 1, 2019 |
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Feb 1, 2019 21:32
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Have you seen my apex seals? I seem to have lost them.
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| # ? May 22, 2024 07:55 |
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