Can we put this to bed? Duo sound issue fix

[omnedon]

This is starting to drive me nuts. I'm getting e-mails about fixing the heat related sound issue that some Japanese and US Duo's suffer. There has got to be a fix, since it's obviously heat related.

I know this is D-Lite's forte, and I'm hoping he can share some of his hard won R&D on this topic.

The Problem:

You play your Duo, doesn't matter if it's HuCard or disc. Around the two hour mark, the sound starts to crackle, before it fades out completely. In fact, the sound is not really *gone* but it's volume is SEVERELY reduced. If you crank the reciever you have the Duo attached to, you can still hear the sounds, slightly distorted and very quiet. If you let the unit cool down (I mean waaaay down, 2 hours +), it can be restarted again, with full sound function, but the problem will re-occur in a shorter time period.

In my opinion, this just screams *heat problem*. What's odd, is how long it seems to take to cool down, for the problem to go away. I suppose this could be heat affecting the IC that controls the sound, but I'm guessing No. The sound is still there, just quiet and lo fidelity. I'm guessing the heat is affecting the amplification parts of the circuit.

I'm going to start theorize about things I only partially understand, so bear with me.

If it's the amplification that is cutting out, then does that not point to the problem lying with the capacitor (or capacitors) in the sound amp circuit? Can heat adversely effect capacitor function? If it's not a capacitor failure, what other component in the circuit is more likely to fail under high heat conditions? There are a LOT of caps in VERY close proximity to the heat sinks that are trying to dissipate all of this heat.

As I venture further into guessland, what if I replaced the cap or caps that function in the sound amplification circuit? What if I relocated them elsewhere, by simply removing the existing ones, replacing them with same rating caps, and running wires to the new locations (ensuring accurate polarity of course)?

Am I onto something here? Is there something in the amp circuit more likely at fault that may benefit from a relocation?

I've considered active cooling, but then you get into a case mod, which would likely ruin the clean lines of the Duo, plus add noise. There has to be a better fix.

If I'm making some sort of big assumption, or am making some obvious error, I would LOVE to be schooled. That's why I'm posting.

Any ideas peeps?

[D-Lite]

Hey man, I got your PM and saw the topic here and at NG.com, but I figure this is probably the best place to post it.  I did send a synapsis of what I think is the problem in a letter the Turbo-List about 8-9 months ago, but you may not have seen that.  

I'm 99.6% sure the issue with the sound circuit is due to overheating as you say.  One way I am trying to combat this issue is with a preventative measure, installing a fan.  I've installed fans on 3 different Duo's now and all reports are that they work really well.  If I can find the pics I took, I'll post them.  I install the fan where the AV port currently is, removing it in favor of the S-Video and RCA mods I do too.  This fan is then situated right next to the enormous heat sinks in the original model Duo and the heat dissipation is very noticeable.  The top of the Duo above the HuCard slot typically is very warm to the touch within 15 minutes of play time, but with the fan on this never heats up!

Now, why does this/should this work?  Well, I've noticed a very important fact.  Original Duo systems are MUCH more unreliable than Duo-R or RX systems.  Why?  The CD units are identical.  BUT, the AV port is in a different location whereas the heat sinks are still in the upper left.  Upon closer inspection, the amps for the sound are DIRECTLY behind the heat sinks on the original Duo but not on the R or RX!  The amps are this small 8-pin SMTs and include a couple of caps as you mention potentially being the cause.  I did some research on the chip and it is a audio amp circuit, but wouldn't ya know it, is only rated to 80 degrees!  Not good my friends.  I've bought some of these chips to try and the caps are standard fair.

But.

The problem is that the sound issue is separate from the CD read issues that some people see, yet this is difficult to diagnose.  I believe I currently have in my possession a Duo board with ONLY the sound issue.  This is because I found it while modding a system for someone, swapped boards, and now received it back to play with.  It is critical that the difference between the sound and CD issues be clear when attempting to solve the problem which I now think i can do.

So, long explanation/theorization/rationalization.  No data to prove it works.  Yet

[omnedon]

That's awesome D-Lite!  8-)


I'm going to look at moving the sound amp circuit, just for the hell of it. See if there is more than one way to skin a cat.  

I just took a quick look at the board with the fresh eyes you' have given me.

I'm assuming the amp IC is the one at R691 . The IC itself the small 8 pin 4558 2908.

For the hell of it, I may still try to move it. however, I can see the elegance of the solution you've done by moving the AV jack. Even without an S-vid mod, it's easy enough to tap composite and audio from a removed A/V port, and mount jacks elsewhere.

Thanks again!

[omnedon]

Quick question- which IC is the sound IC on the Duo, and does it handle controller input as well? Is it the same IC that the TG16 uses?

[omnedon]

I now have ANOTHER one of these. This time a TurboDuo.

I've actively cooled the TurboDuo (moved AV, added a fan), and it can now play Hucards for HOURS with no sound issues.

CD music is mostly AWOL though. Sound effects in CD games are fine, but CD music is gone.

I've repaired a lot of systems, and I'm beginning to consider Duo's as temperamental as PS2's.

If there is any info I can share with D-Lite (test results, pics, other useful specifics) they are his for the asking.

I was gonna buy a Duo. I'm beginning to change my mind. If this fix doesn't pan out, I may begin to consider them junk...



EDIT:

I have the opportunity to buy a NEW Turbo Duo. Yes, you read that correctly. N E W in box, turned on once. I've seen it, and it is indeed new. I was going to buy it for myself (it's wicked expensive, but the guy who has it owes me big $$$), but running an errand I had an idea.

Perhaps I can use parts from this new flawless Duo to test some things out. For example, I can pop it's laser into this latest TurboDuo with no CD music sound, and VERIFY it's not the laser for example. Perhaps some tests on the new one's components, could reveal the source of sound amp circuit flaws.

The thing is, if this is even useful for reference, I need help deciding the best way to approach and test.

If this new Duo could help in the R&D for this problem, that would be enough to push me over the edge and buy it.

:blink:  

[Shimarisu]

I was under the impression Duos die quickly because they were the earliest models, used a lot at the height of its popularity - later models during the end of the PCE's life were obviously used less.

That's my theory for the CD ROM drives going anyway. Because yeah, identical CD-ROM - but a heck of a lot more broken Duos out there than the latter models.
I've been through 3 myself,m but my Duo R is still going strong.

[omnedon]

I think I am on my own.

[D-Lite]

I think I am on my own.

Don't you worry slick.

I'm just under an enormous pile right now.  I'll be getting to it too.  Getting a nice multimeter for the holidays that should make the job easier too.

[omnedon]

Me too.

I wish I could give these more time, but I've had an avalanche of PS2's and Xboxes, that everyone needs done to save Christmas.    

[Shimarisu]

Hey,

If any of you out there have a Duo with JUST the sound issue on the board, I have 3 working boards here if you're interested. I can take them out of the Duo or ship a Duo to you with just the CD removed. If you're interested I'll send one for $20 just to get rid of them. That's including postage from Japan. Or I'll buy your working CD ROM, how about it? May as well salvage something here.