Dead PCE Duo, please help

[segasonic]

I got rid of my Duo in '93 and have regretted it ever since, now after 13 years have finally got another one, which I bought knowing it isn't working. I figured it's worth the gamble as I have a pretty good luck/success rate with resurrecting dead electronics.
It's a Japanese Duo, boxed and in great condition, but it doesn't power up. I've checked the obvious things without success, but discovered that there doesn't seem to be any power getting to the internal fuse when checked with a multimeter. There is power at both ends of the red/brown cable.
I've already trawled the forums for the same problem so I didn't ask something that's been asked a thousand times before.

Can anyone offer any advice? I understand that the caps can be dodgy in old Duos? Any particular component that commonly fails? Perhaps the big diode before the fuse - if so how would I check if it has failed?

If anyone can help it would be greatly appreciated.

[kendrick]

I've only repaired a half-dozen Duos (as opposed to the piles and piles of Saturns and Xboxes) but in almost all of them, I found lots of cold solder joints. These were typically found on the A/V plug, which made sound and composite video intermittent and dodgy. I wouldn't be surprised to find them on the power connector or any of the big capacitor leads either. That's as much as I can suggest without actually seeing into your unit. How about some pictures?

-KKC, filing taxes. Woo.

[Guest]

I must be the only person on the planet without a camera

http://www.multimods.com/images/Sales/R10x600.jpg

I've linked this pic from D-Lite, I hope he doesn't mind.

Power connector seems ok as there is power to the main board through the red/brown wire that runs from the power connector on the left of the pic. There doesn't seem to be any power across the fuse below where the red/brown wire connects though.

Thanks for your reply, I couldn't see any obvious dry joints but I'll have a closer look tomorrow when the other half is at work.

[segasonic]

PC-Engine Duo status has been upgraded from 'dead' to 'alive'! I built a UK spec PSU out of an old IBM PSU (10v 1a), resoldered the diode next to the internal fuse, lo and behold, PC Denjin works! Put in Image Fight II CD, and it also works! CD audio seems perfect thankfully.

That's made my day!

[kendrick]

Cool beans. Did you actually have to replace the diode, or did you just redo the solder joints on the existing component? Either way, good job.

Re-reading your post, it occurs to me that there's a standard Radio Shack part that's been running my Duo-R unit flawlessly for a couple of years now. I can't find the part number now, but I'll post again after I get home and peek behind the shelf.

-KKC, who should add that to the Wiki.

[segasonic]

I just resoldered the diode, no need to replace it. Must have been a dry joint.

I think the Duo-R uses a 9v supply, whereas the original Duo PSU is 10v, probably makes no difference though unless the current is different? Original Duo is 10V-1A and apparently if you go any lower than 1A you get weird behaviour such as the screen dimming during CD access. I built mine from a PSU for an external laptop CD drive which luckily has the same power spec and works perfectly. The one that came with it is a Japanese 2-pin 110 volt and I'd rather not have to use a stepdown.

Our (UK) Radio Shack (Tandy) went bust years ago, but the part number would be useful I'm sure to you guys on the other side of the pond.

I'm like a kid today, all excited and reliving my youth

[thumpin_termis]

Good on you.  I'd hate to see another Duo hit the dumpster.