Author Topic: PC Engine DUO issues  (Read 460 times)

VGplayers and Haters

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PC Engine DUO issues
« on: June 25, 2020, 07:32:48 AM »
Sorry for this being my First post on this forum.  Also i have read though the Forums and even used some Guides but i am still having issues so i decided to post a new Thread for my issues.

ok now to my story:

I got for very cheap and in non-working condition.  when it arrived It was covered with some kind of Grease, smoke or Tar. it also looks to have been spayed with some kind of bug killing substance, anyway it was also full of presents(dead bugs) when i opened it and cleaned it out.

The System was playing Hucard's but the CD bios looked corrupted. I started to test and applied some pressure around the Cap's by the red and white connections on the left hand side of that. this made the Bios corruption  clean up. then i tried loading a game and it loaded up with some pressure being applied( i think). So after this i decided to continue to clean up and recap the system in hopes this would solve the issue. well it did not. after recap the system stopped loading up games. but looked like it was trying. I then noticed the BA6290A chip was getting extremely Hot very quickly. maybe only after a few minutes of working. I know they normally get hot but this was way more than normal and the disks stoped spinning. So i tried Adjusting the pots Stupidly i tried all of them and forgot to mark the board(not sure why a Brain fart maybe). So i decided to give replacing the BA6290A with a good one from a CD rom rom drive i have. I also at this kind reflowed everything on the top and Bottom pf the PCB on the CD since of things. This made the disks start to spin again. but it was still not loading up any thing. so i tried adjusting the pots again and again. Using a few Guides posted here. To no success. At this point i noticed that the pot started to ware down and the readings started to fluctuate a lot. i tried matching it too a few configurations(for Pots) i found online and here but no luck. So i did the right thing and picked up another Duo. This one also had some issues and i managed to fix it. So now having a fully functioning one i decided to swap the lens and found that the lens was not working on the new working system. so i ordered a two new ones and also pot replacements 10k,20k and 500ohm. I also picked up an analog oscilloscope(100mhz) for a good deal(i needed one anyway) This brings us to present time. I have replaced the laser with a working one(tested on a working duo) I have replaced all the Pots and adjusted them Using the by ear and oscilloscope without any luck.  Any tips or suggestions would be great.

Check out my video below of the System running and how it looks on my oscilloscope  and the current Pot settings. Also you can hear how it sound when trying to boot a disk.

https://youtu.be/aPaX-m6YSaQ

Thanks again for any help you can provide.

Keith Courage

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Re: PC Engine DUO issues
« Reply #1 on: June 26, 2020, 10:58:47 PM »
Did you take a look at the adjustment guide found here? https://www.pcenginefans.com/forum/index.php?topic=8926.0

Kind of difficult to diagnose what to adjust without seeing your DUO in person.

VGplayers and Haters

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Re: PC Engine DUO issues
« Reply #2 on: June 27, 2020, 02:50:39 AM »
Yes I used this same Guide to help me repair a different system. Its a great resource. but sadly with the Duo in the video i have had no luck.i can get the Pots set to the point of the lens being pretty silent but it just does not want to load anything up.  yeah its not easy to Diagnose without seeing it in person but i figured its worth a shot to see what people think.