CALL FOR DEAD DUOS

[D-Lite]

Okay, this is gonna sound SUPER chumpy, but my Duo sound is working right now and that's all that matters. Ready to hear my super-duper fix? Are ya?

I left it on.

So I was getting kinda mad and depressed about the Duo sound problem, although I was a little heartened by the fact that I wasn't alone and that it's a common problem. So I was trying different CD and SCD games in it with no luck, then I put in YsI&II. No sound. I went to do something else, leaving the game running and just looping the intro. After maybe 10 minutes, I heard the CD music swell up. Fully expecting it to fade out again like always, I left it on. Amazingly, the sound didn't go away. In fact, I tried a few other games -- KO Beast, Snatcher Pilot Disk, CD Denjin -- and all of them worked fine, with full sound, from the word go.

I know it's a stupid quick & dirty fix, which can't even really be considered a solution to the problem, but maybe the darn thing just needed to warm up a little. I hadn't used it extensively in a while. Has anyone else tried this?

I'm still looking for a broken system for someone to either sell or volunteer for tests.  I'm pretty sure I know what the problem is in these systems.  If anyone is interested, please PM me.

I'm still dealing with the issue, but I'm starting to more and more doubt that it's a straight PCB issue, instead believing it's the drive.  I've tested the caps and they don't seem to be the issue.  I am working on acquiring some drive units now.

[larsulrik]

Hey D-lite what's the status of your experiments?  I just pulled out my duo that hasn't played cd music for a few years and decided to do the "let it run for a while trick" with a music cd.  After about 30 minutes it started to fade into perfect sound, for the first time since it went out years ago.  Then after a few seconds back out.  It's been doing that for the last 30 minutes now but each time fading out less and working correctly more.  It almost sounds like something in there is dirty like with old stereo tuner controls.  Mine has all of your listed symptoms where the hu card music/fx/cd fx play fine.  Anyway, just wondering.  Thanks!

[larsulrik]

Quick update to my last post.....Has been playing with no fade outs for about 2 hours.  The problem initially surfaced after a few years in storage, not after continued use.  I wonder if something got "rusty" and needed a good "flushing".  Of course I have no scientific basis.  I still don't consider this issue fixed.

[monads]

Through correspondence with D, he just received the laser assemblies in so we'll see how the testing goes.  I really miss my Duo    Come Home...when you're ready and all fixed  

[larsulrik]

Do you mean the cd laser?  Is that a seperate problem you're having because I know duos with the red book audio problem can have the cd assembly, laser and all, transplanted into a working duo/r/rx and work fine.  Maybe you're not talking about the same thing though.  

[D-Lite]

OK, here's an "update", of sorts and some more ill-founded conclusions  :oops:

So, I got some new CD units in (the CD unit, not the motor part) and slapped one in the Duo with the most problems.  This Duo had good Hu play and sound, but the CD drive was super problematic.  Didn't load games well at all, lots of hanging, horrendous sound, you name it.  Put in a new CD assembly and it works!  Perfectly!  No load issues.  No sound issues.  Perfect!!

So what does this mean.

Well, I still believe the problem is on the PCB.  The main reason I believe is as larsulrik mentioned above, a transplanted CD unit sometimes will work better in a DuoR than a regular Duo.  Also, the sound issue is much more prevalent in a regular Duo than the R or RX.  And one of the main differences in the systems (and there are few) is the capacitor type they use in them.  The R and RX use mainly radial caps instead of surface mount and the rating seems higher.  

One of my successful "revivals" of a seemingly sound issue Duo was taking a known working CD unit and putting it with a PCB that had bad redbook audio.  The sound came back when I crossed in a couple of new capacitors during gameplay.  After the sound came back, the system was fine and has been since WITHOUT leaving the new capacitor attached!  Just leaving the old one in place.

What am I getting at?

Well, it seems that the problem is even illustrated with the above example of the fading in and out after years of storage.  Sound fading and crackling is likely due to a capacitor issue.  And the typical problem with a dead capacitor is it either dries out or loses charge.  Capacitance is based on building charge between two plates and without it sound won't work right.  So perhaps after years of storage the lost charge in the cap is restored with extended gameplay.  And perhaps with extended gameplay (and resulting heating) the cap dries out a bit (if borderline to start with) and sound takes a shit.

So why does replacing the CD drive help?

Because that can be a problem in addition to the capacitor issue.  If the lens needs to be tuned or is dirty, the system is going to have one HELL of a time playing properly and with such early CD technology you need all the help you can get.

So why does a drive work better in a R or RX and why are they more reliable?  

I think the case is that the later (relative to the original Duo, not each other) R and RX models have better error correction on the board.  That or the more robust caps help out with these.  A drive that is out of tune and fails on a regular Duo may therefore work better on a R or RX.

So, all that said, I have a lot of work to do.  I have TEN Duo systems on hand that have audio issues.  TEN.  That doesn't include the two from members here that are hoping for a fix!  I hope to have more info on what does and doesn't work in the near future.  Busy life doesn't make that testing any easier  

[esteban]

D-Lite: even as a non-techie, I found that post accessible and enjoyable to read. Thanks again for taking the time to update us on your efforts -- we await your next update!

[larsulrik]

Awesome D-lite, thanks!  Very strange our Duos are.  I guess that's the price you pay for having sweet first generation technology and expecting it to work right 13 years later.

[KingDrool]

Thanks D!

The CD laser in one of my Duos is completely dead, so if you figure out how to fix that, I'd love to send you my unit for a fix and a regional mod.

[Keranu]

Thanks for the excellent information, D-Lite. I am going to be sure to power up my Turbo Duo whenever possible so it doesn't have any problems. By the way, will you ever look into the PCE CD's problems more in the future? It would be nice to understand more information about it's problems as well.

[zborgerd]

Thanks for the excellent information, D-Lite. I am going to be sure to power up my Turbo Duo whenever possible so it doesn't have any problems. By the way, will you ever look into the PCE CD's problems more in the future? It would be nice to understand more information about it's problems as well.

You can't stop capacitors from failing, but they can ultimately be replaced.  Electrolytic capacitors have an electrolyte that (as D-Lite mentioned) can dry out over time, reducing the ability for the cap to charge.  There is, unfortunately, nothing that you can do to stop this from happening.  It solely depends upon the electrolyte and the general construction of the capacitor.  As manufacturers cut costs to produce these things, the quality seems to be dropping as well.

During the '90s (particularly in the late '90s but all the way through 2002), there were a lot of bad electrolyte solutions out there.  It's certainly possible that they could stretch back to the date of the DUO manufacturing.  The fact that the DUO has such common problems like this has always led me to believe that there were some faulty caps that were used in the construction of the system.  Hard to tell if it's somehow related to all of the caps that were blowing up in motherboards several years ago (I was one such victim).    I think that D-Lite mentioned that the overall condition of the faulty caps *looked* fine, so it sounds like it could be a different problem.

I've long suspected bad caps as being the culprit, and I believe it's something that only affects DUO systems (but not systems with the CDROM addon).  I still really want to get my hands on a bad DUO.  If anyone wants to sell one or supply it as a test system (which I would be willing to attempt to fix for free with no guarantees that I have the solution to the problem), please send me a private message.