Pc En gine Duo won't power on

[darthkur]

To my utter dismay last night when I went to play Volfied for the TG16 HSC I discovered that the PCE Duo refused to power on. It worked fine the last time I had it on not too long ago. Why would it just die sitting there? I opened it up and can't see anything obviously wrong. The fuse is still intact and the AC adapter is functional. Anyone know what's causing this and how to fix it?

 

 

 

 

 

 

More pics here: <iframe width="480" height="360" src="http://s17.photobucket.com/user/DarthKur/embed/slideshow/PC%20Engine%20Duo"></iframe>

Edited November 26, 2013 by darthkur

[CGQuarterly]

Visually inspect all of the caps for swelling, and also check the switch to make sure that it's working. You can use a multimeter to follow the power around the board and see if you can isolate things. If you can't fix it, there are a couple of dudes on the pcenginefx forums who do repair work.

[darthkur]

None of the caps look swelled nor did I detect any leaks. The switch appears to be in operating condition and there's no breaks in the solder. I really don't have the knowledge necessary to know how to go about the other task but do know a couple people that hopefully do. Unfortunately they would have no familiarity with this console.

[FABombjoy]

Possibly the SMD caps have failed to the point that the system will not function. They are pretty much guaranteed to fail on all Turbo Duo / PC Engine Duo units. Replacing them all is the first step in troubleshooting, and depending on if there is any damage to the PCB, further troubleshooting afterward. Examine the legs of the SMD caps and see if they look corroded. That's the only real way to tell with them.

 

Here's a pic of what to look for. The right leg on that SMD cap has been damaged by the leaking electrolyte, but there is no presence of liquid and the cap itself looks fine.

 

Edit: Added pic

Edited November 27, 2013 by FABombjoy

[darthkur]

Thanks very much for the visual aid, FABombjoy. With the knowledge of exactly what to look for I found the probable culprit. Fuses C125 and C149 exhibit the corrosion you showed.

 

 

 

 

I probably should have them all replaced so this doesn't happen again soon. Not sure I can manage it even with help. Would hate to fry anything else.

[Osgeld]

there are a number of other capacitors (not fuses, but whatever) just in your images above that look to have nastyness, like in the first pic, on the top right, looking at its foot its kind of rusty looking, there appears to be some juice around it, and the via (small hole that connects to the other side of the board) is also messed up along that same trace.

 

So yes you want to not only replace every one of them, cause what good is it to replace a few, just to have another bad batch 6 months down the road, but also thoroughly clean up any leaked juice (its corrosive to any exposed metals) and check any other corrosion to make sure its not a broken open trace. That may sound like a lot, but anyone with experiance working with electronics should be able to knock that out in a couple evenings ... you could do it, but the hardest part is removing the caps without peeling up the tiny ribbon of foil on the mainboard.

[FABombjoy]

All SMD caps will probably be bad. I've done more Duo / Express / Laseractive PAC cap replacement than I can remember and the failure rate is pretty much 100%. Unfortunately, the longer you wait, the more frustrating repair can be.

[ApolloBoy]

Fuses C125 and C149

Those aren't fuses, they're capacitors.

[darthkur]

Those aren't fuses, they're capacitors.

 

 

Woops, don't know why I typed that. I know they're caps. Might have been thinking about the one fuse one there since it was the last picture I uploaded. Oh well.

[+save2600]

...anyone happen to know what kind and what size security bit is needed to pry open a CoreGrafx?

[ApolloBoy]

...anyone happen to know what kind and what size security bit is needed to pry open a CoreGrafx?

It's just a standard 4.5 mm gamebit, same as the SNES, TG-16, N64 and several others.