PC Engine Duo sound problem

[DarthKur]

I was playing a few games on my PC Engine and during game play the sound started getting full of static. It progressively got worse until the sound started dropping out. I assumed it was the recently acquired game so I replaced it with one I've had and not only did static and drop outs persist now there's no sound at all. Needless to say this is extremely upsetting. I don't have a set of headphones to plug into it. I'll have to get a hold of some to see if at least that will work. I wanted to dissemble the console but of coarse NEC had to use those irritating proprietary bolts.
Has anyone else experienced this same malfunction? I'm hoping it's just a broken lead attached to the A/V input.

[Tommy]

Try replacing your AV cable. Hopefully that is where your problem lies.

[Ze_ro]

Sounds like dead capacitors in the audio amplifier. Which model is your system? The original white PC Engine? It is a common problem with Turbo Express, PC Engine GT, and Duo systems where the audio circuitry dies either due to bad capacitors or overheating (or maybe a mix of both).

--Zero

[Aussie2B]

Unfortunately, that's a very common problem for PC Engine systems. I doubt replacing the cable will help you. I suggest you do a search in the technical forum, where you'll find lots of topics related to the issue, and they should help you in determining how to tackle the problem.

[bust3dstr8]

Here's a pic for the DUO caps
http://www.pcenginefx.com/forums/index.php?topic=960.0

[kazuo]

Is this problem with HuCards, CD software, or both?

This is extremely important to know in order to properly diagnose your problem.

[DarthKur]

Firstly, thanks to everyone that replied. To answer a few questions; my console is the first version black duo with the headphone jack and the sound issue concerns both cd and HuCard games.
Upon reading the information on the link, http://www.pcenginefx.com/forums/index.php?topic=960.0 , it appears that problem #2 seems to be, most likely, the one I'm dealing with. Looks like I'm going to have to do some soldering.

[InsaneDavid]

Do check the cable first though. I was getting dropout on the right stereo channel and it ended up simply being a broken connection in the red plug. I would also get CD audio skipping problems every now and then but that turned out to be the magnet on the disc lid getting hung up and not spinning smoothly. Thread about that here. Not to say that the capacitor issue doesn't exist, but eliminate the simple external stuff first. Everyone seems to want to jump to the caps when a 'Duo develops any sort of problem - that's bad engineering.

You may also want to change the title of this thread to reflect that you are having problems with a PCEngine Duo and not a standard PCEngine.

[DarthKur]

I turned the unit on this morning to try out a pair of headphones I borrowed from my neighbor and was somewhat surprised to find that the sound had returned. I plugged the headset in anyways and that function works properly. By the time I took the headphones back next door and got back inside the sound had gone yet again. I did make sure to move the A/V cord around both at the base and the cable in general when the sound was working but that had no effect. The audio did not fluctuate or cut out at all. Logically this small experiment seems to remove the A/V cable from the equation and seems indicative of the capacitors being at fault after all. Of coarse it very well could be something else entirely. Unless there are other suggestions on alternate procedures I'm going to have to look into replacing the capacitors. I figure I might as well do all five of them while I'm at it rather than have similar problems down the road.

[InsaneDavid]

Logically this small experiment seems to remove the A/V cable from the equation and seems indicative of the capacitors being at fault after all.

It does everything but. If audio output was working fine through the headphone jack then your audio output is fine. Before you go replacing components, try a replacement 'Duo AV cable.

[DarthKur]

I should have clarified that when I tried the headphones the sound was working through the TV as well. You made a good point so I later re-borrowed them, after I hooked up the console again. As before the sound worked at first so I played a bit of Altered Beast and unfortunately the sound ceased to emit through the television once again. So then I tried the headphones while the sound was not coming through the TV and sadly nothing was present though the headphones either. So with that further evidence can the A/V cable be ruled out?

[Ze_ro]

The sound problems on Duo machines often cut in and out like that, where the capacitors will sometimes hold a charge and then sometimes not. For two straight days, I got no audio from my Duo, and then today I tried playing Blazing Lazers, and I was surprised to find that I could hear the music... unfortunately, it got really staticy and crackly and eventually died out again.

--Zero

[InsaneDavid]

So with that further evidence can the A/V cable be ruled out?

Yup, the caps are the next thing to check. Just making sure that you don't have to do more work than is needed.

[DarthKur]

I was hoping it would be the cable. It would most definitely be much easier to replace it than the task that lies before me now.

[omnedon]

For those who do not like surface mount soldering, this repair is something OSG offers, and usually does at least 1 per month. They usually run between $69 and $89. They vary, because unlike the online guides, each one I see is a little different. Some require different steps, different caps, other issues exist, etc.

If you do go DIY, spend the money on quality desoldering stuff. A bulb and an iron may not be sufficient for surface mount stuff. Get some braid for sure. Once you start tearing traces out due to a flaky desolder, it makes a tricky job much harder. Screwing up your DUO mainboard is not the desired result you want. Fixing failed installs is always more work for us than a straight up repair, and is usually more expensive than a straight up repair.

Good luck with it, and take your time.

[DarthKur]

Thanks for the advice. I will definitely take care. It took me a long time to finally acquire a Duo in the first place. The last thing I want to do is ruin it.
I'll post later, after the procedure.

[FABombjoy]

In my experience, you can use pliers or a hemostat to wiggle those little caps back & forth, and they'll pull straight up and off of the board. They leave behind 2 little metal legs that new caps can be soldered directly to. I've done cap replacements on several Duos and Turboexpress units and I don't think I've ever actually had to desolder anything.

[DarthKur]

That sounds like a good idea. I will try that. Thank you.

[klausien]

I recommend only using a desoldering braid for surface mount work. It will clear everything down to the metal and keeps you from holding the heat on the board for extended periods. So much easier to deal with than a bulb. Use alcohol & a q-tip to wipe up any residue left by any leaking caps. Then wipe some flux on the exposed metal and make new pads with solder (I find that gathering a bit on the iron and simply touching it to the points makes a nice bead. Not the most professional method, but relatively fool-proof). Easy as pie. Now you have a fresh, clean set of solder points for your new caps.

[Ze_ro]

In my experience, you can use pliers or a hemostat to wiggle those little caps back & forth, and they'll pull straight up and off of the board.

I'd be careful about that... you could potentially pull the contact pads off the motherboard, and then you'd be left with nothing to solder to!

--Zero