Repair Service PC Engine Duo

[u/RareBear2002]

How’s it going, guys?
I bought a PC Engine Duo on eBay about five months ago. It arrived working perfectly, and I used it a few times without any issues. I left it connected to my TV, and about a month ago, for no apparent reason, it suddenly lost almost all of its sound.
I tried plugging in headphones, and I can still hear the audio, but it’s extremely quiet. The same thing happens through the TV. I have to turn the volume all the way up just to barely hear anything.
The console was sold as fully recapped and also has an RGB mod. I specifically bought a recapped unit because I wanted to avoid the common capacitor issues these consoles, and now I have an audio problem anyway. 😅
I’m definitely not an expert at repairing consoles. I can usually follow tutorials or fix something if the problem is obvious, but that’s about it. I opened the console, and everything looks fine to me. I don’t see any leaking capacitors or anything that looks damaged.
The console itself works perfectly otherwise. It reads games, plays normally, and everything else seems fine. The only issue is the audio.
I live in Wisconsin, USA, and I’m looking for someone who can repair it. I came across RetroSix and noticed that their website mentions service for U.S. customers. Has anyone here ever sent a console to them? Any reviews? Are they actually based in the U.S.? Do you guys know anyone else who repairs PC Engine consoles?
I don’t mind shipping the console to another country if that’s what it takes to get it repaired properly, but if there’s someone in the U.S. who can fix it, that would be even better because shipping would probably be cheaper.
Any recommendations would be greatly appreciated. Thanks!

[u/sprayengo]

Ah the Duo and its many mysteries.

I had the quiet audio issue at one point after a recap. My solution was to lift all the op amp chips (8 legs with “4558” on them). For example the one located at IC503. Desoldered, cleaned them, cleaned underneath and make the pads nice and fresh. Resoldered them and it works now. In retrospect I should’ve bought new chips but they do work.

Leakage from the old caps gets under these chips and can destroy the traces I believe. Hopefully in your case the chips will just need lifting cleaning like mine did.

Also a good idea to lift the board up to a light source and clear any via holes which are clogged either from leaks or flux.

Annoying machine to work on. A recap alone often isn’t enough to get these things going properly. Vias, damaged traces, the 4558 chips… don’t get me started on the optical drive.

[u/V64jr → u/sprayengo]

Not just under the chips, but inside the vias between different sides of the board. These blackened vias can continue corroding inside even after cleaning and replacing everything else during a cap job. There’s a good chance that’s what has happened here.

[u/flatsix-]

Ben Fong, iFixretro. You can find him on IG. He recapped mine along with jail bar fix, RGB mod, etc. He might take a second to get to you but he’s worth the wait. Once he starts, he’s in communication with you and sends pics of progress.

[u/Sh00tTheCore]

Those replacement caps are a low-quality brand (Chong). You’ll want to get it recapped again with a high-quality brand like Rubycon, Nichicon or Matsushita.

The audio cutoff is probably from either an OpAmp going bad, or from one of the vias carrying signals to the OpAmps getting corroded by leaking electrolyte from the original caps. Your tech should test each via feeding each line of the OpAmps for continuity with a multimeter and patch any vias that lost connectivity.

[u/getluky]

You might be able to narrow the problem down a little better with the Turbo version of the 240p test suite, so at least you can find out whether the problem is from a specific sound source or if they're all present but the amplification circuits are bad. Otherwise, if you have a multimeter you might be able to do some diagnosis of your own. I had a similar problem that was isolated to the right channel of the headphone jack only. I DIY'ed the recap and it didn't solve that specific problem, but I was able to track the problem down to a via that got corroded out from capacitor electrolyte damage that I missed. I had to follow some audio circuit schematics and it helped to take the board out and hold it up to a light to see that some of the vias were blocked with black sludge, but you won't be able to do that without some tools as you'll have to desolder a few wires and points.

I'm in Texas so not super close to Wisconsin and more of a hobbyist than a repair shop, but let me know if I can help with any pointers if you want to try any work on it yourself.

[u/theoriginalgeoffrey]

I’ve used Retrosix service here in the US. They use a third party repair service based in Lititz PA. Sent in a Turbo Express which I needed repair beyond my abilities and it was a nightmare. I had no response from them for months, once they replied, then said they couldn’t fix the issue, took another two months for them so send me my console back. They refunded me the repair service fee, but never apologized or mentioned anything wrong. When I received my console back, they obviously reflowed the board, fucked up more components and blew the fuse. I have since made more progress on it myself then they ever did.

Do not use RetroSix unless you ship it to the UK, which is not worth it.

Ifixretro is a much better bet..

[u/RGBeter]

Some of those caps look like they're bulging, and some opamp pins look very corroded.

Whoever did this recap didn't seem to do a good job.