PC Engine Duo-R doesn't power on :(

PoV · 04/21/2008, 03:05 PM

Hi there,

My apologies that my first post has to be a repair question, but it's kinda difficult to talk games or homebrew without a working system. ;)

Anyways, I picked up a PC Engine Duo-R from a guy in town. It was missing the video cable which was fine. I hacked one together from a composite video cable and DIN connector I conveniently had. That's not the problem though.

My problem is the system doesn't power on.

I'm here for some advice. I spent enough money on this system just to buy it, I'd like to fix it myself. I'll start by talking through what I have done, and if that doesn't help, I'll take photos.

I've tried pushing the RUN button with power in and on, to hopefully make the CD ROM do something. No dice.

Power is getting to the board via the power connector. I've plugged one of those Radio Shack universal tip connectors in, and traced it's pins to a solder blob (GND), and the video connector (+5V DC).

I can't find a fuse on the board anywhere. Mind you, I'm looking for one of these when I think fuse.

I'm hoping it's not capacitors. From a visual inspection, it doesn't appear to be. I've never had to swap out caps to fix a device before. I'm not afraid of it or anything, just know it'll be work getting the parts and doing it. I have had a computer motherboard that turned in to a beautiful cap leak mess, so I do have an idea what to expect, but I'm assuming you can also have a bad cap that looks fine.

For the most part, the board is pristine. There's a couple screws with a little bit of rust or discoloration on them. On what I think are Voltage Regulators attached to vertically mounted heatsinks, there's what looks like thermal grease leaked between them and the heatskinks.

Power wise, it actually did not come with the NEC power supply. Instead, it came with a 500mA Radio Shack universal. The case is marked saying it takes a 9V +TIP plug. I saw it suggested here that some of the systems take 1200mA 9-12V power, but since this was marked 9V I didn't want to risk pushing 12V. I did briefly try a 1500mA power supply at 9V that made no difference.

So that's what I've done. Any suggestions you may have, I'd love to hear them.

Even if you want to question how I performed my tests, go for it. I'll gladly take any ideas/critique you may have. Admittedly, I've only really done the most basic of electronics work. Soldered parts and connectors to a board, assembled kits, followed schematics, and basic experiments with LED's/batteries/caps and resistors on a breadboard. I come from a programming background, and have assembled computers for many years. But hardware, chips and solder, are still new to me.

Thanks!

nat · 04/21/2008, 03:16 PM

Quote from: PoV on 04/21/2008, 03:05 PMHi there,

My apologies that my first post has to be a repair question, but it's kinda difficult to talk games or homebrew without a working system. ;)

No apologies necessary. And welcome to the forums.

Quote...
lots of other stuff, power doesn't work, etc etc

The board has a fuse on it, I'm sure of it. I've never been inside a Duo-R, but many NEC systems use non-glass type fuses that look more like this:

For example, the TurboExpress/GT uses a ceramic fuse of this type but black instead of white.

When you push RUN with the power on to see if you can get the CD-ROM to do something, do you have a CD game inserted and the lid closed? If the lid is open and/or there is no game the CD-ROM won't do anything.

PoV · 04/21/2008, 03:34 PM

Quote from: nat on 04/21/2008, 03:16 PMThe board has a fuse on it, I'm sure of it. I've never been inside a Duo-R, but many NEC systems use non-glass type fuses that look more like this:

For example, the TurboExpress/GT uses a ceramic fuse of this type but black instead of white.

Yeah, I can't even find one like. There are few components in the Duo-R that aren't obviously resistors or capacitors. I'll have to take some photos.

QuoteWhen you push RUN with the power on to see if you can get the CD-ROM to do something, do you have a CD game inserted and the lid closed? If the lid is open and/or there is no game the CD-ROM won't do anything.

Hahaha! I was sure I tried that with the drive close. Apparently I didn't with the 1500mA power supply.

It works! Thank you very much.

nat · 04/21/2008, 03:38 PM

Heh, gotta be smarter than the Duo, PoV, smarter than the Duo.

Glad it's working for you.

NecroPhile · 04/21/2008, 03:39 PM

She'a needs more powa, captin! (insert lame-ass Scotty impression)

Good to hear that the only problem was an inadequate power supply. Welcome aboard, by the way.

PoV · 04/21/2008, 04:44 PM

Quote from: guest on 04/21/2008, 03:39 PMGood to hear that the only problem was an inadequate power supply.

Yep. No LED's, no movement in the CDROM, and no video certainly casts doubt if it works at all. ;)

I've actually discovered more problems with this particular system, but the rest I can handle. ;)

It seems my video connector on the board is loose, and I had to fiddle with the cable to get a picture. So either my cable is flaky (most likely) or the video connector is.

I also neglected to mention that I already de-soldered and replaced the power connector. Ground wasn't making it to the board. I wanted to avoid the obvious "you pooched it" rebuttal, at least until I was sure. ;)

So I fired up the Mysterious Song demo (hey Nodtveidt) and discovered my right and B (II) buttons don't seem to work. Not sure if it's the controller or the connector. I may have to grab a new one to find out.

So yeah, it looks like my PCE's a fixer-upper, but at least the CD ROM works. ;)

NecroPhile · 04/21/2008, 04:56 PM

Quote from: PoV on 04/21/2008, 04:44 PMIt seems my video connector on the board is loose, and I had to fiddle with the cable to get a picture. So either my cable is flaky (most likely) or the video connector is.

It's common for the DIN plugs to need resoldering (tall plugs plus little contact area on the pcb equals too much torque and finicky connections). If that doesn't help, then I'd try a new video cable; redfrog claims to have OEM cables available, but with those goofs I wouldn't be surprised if they're aftermarket.

SignOfZeta · 04/22/2008, 01:20 AM

If the Duo R has a fuse in it its disguised really really well.

I bought a "broken" Duo R from a guy and the problem was also a power supply. Incorrect and broken. Seems to be the #1 problem with Rs other than worn out lasers. The NEC PS wears out and people replace it with whatever junk they can find, which these days is almost always underrated current-wise.

That Radio Shack 9V 1500ma PS is the greatest. You need at least 800ma or you'll have issues.