DUO sound problems...again!

[RadiantSvgun]

I was playing my DUO earlier, and the sound got really low, and then faded out. I can still get some sound through the headphone jack, but its low. Has the DUO overheated? I just got the sound repaired, but the DUO smells like hot plastic, so I'm wondering if thats what happened. Or is it just the Audio/Video cables? I really don't want to send the system back if I don't have to.

[RadiantSvgun]

Even after letting it sit for 3 hours, the sound is still messed up. And when I turned it back on, it smelled awful, like something was burning. I'm using the proper power supply; I'm guessing I'll have to send it back to omnedon since its still under warranty. I had no idea these things are as fickle as a early model PS2....

[ooXxXoo]

It is almost for sure that your problem is the sound capacitor.This is a very common issue with the Turbo Duo's.It can be easily fix simply by replacing it.The problem itself relies with the location of this capacitor,it is very close to the IC regulator Heatsink and it can fried with the heat that the regulator provides after a while of playing.NEC decided to put in there dry capacitors.There is a replacement tutorial somewhere,but you going to have to google around.I don't remember where it is.
What was the problem with your Duo before and where do you send your system for service?

[ooXxXoo]

If you are not able to find it I could send you a picture of the location of the capacitor.I have been thinking adding a cooling fan there,before this problem happens in mine.If that person has replaced the capacitor,maybe missplaced the values.(+,-)

[RadiantSvgun]

The problem before was the sound. I sent it to oldschoolgamer.ca. They do some incredible work, as they also added a region switch to the duo. The sound was working fine until today. However, the site also offers a 90-day warranty, its just a matter of me going into civilization to find a UPS store. I know sometimes old school systems can overheat, or the cables can go bad, but I've already tried letting the system cool, and using earphones, which I can get a very low sound from it. However, according to the invoice, the capacitors weren't the problem at the time. I don't have a soldering iron anymore, and the DUO is something I do not wish to risk destroying.

EDIT: I've unplugged the DUO, since when I turn it on, it smells like death.

FYI. oldschoolgamer.ca is run by the moderator of this forum, omnedon.

[ooXxXoo]

Everydoby makes mistakes.They seem to do some great work and I'm sure they're very reliable.Send it back under guarantee terms.I will recommend not to play the Duo for now.!

[SnowKitty]

if they said it wasnt the capacitors they were probably being lazy. i would have re-capped it either way. i heard that around the early 90s there were some bad batches of capacitors going around. which is a common issue with the duo, geme gear, turbo express, etc. the caps will eventually go bad anyway so i prefer to replace em before they crap out.

[RadiantSvgun]

if they said it wasnt the capacitors they were probably being lazy. i would have re-capped it either way. i heard that around the early 90s there were some bad batches of capacitors going around. which is a common issue with the duo, geme gear, turbo express, etc. the caps will eventually go bad anyway so i prefer to replace em before they crap out.

I highly doubt they were being lazy. I might have just had some bad luck with this unit. But that burning smell is the sound capacitors?

[ApolloBoy]

But that burning smell is the sound capacitors?

Most likely, since capacitor electrolytes have a rather nasty smell.

[ooXxXoo]

Yes they do!..The other day I replaced my NES 2200uf 16V capacitor,by accident I misplaced the values in the board and all hell broke loose when I power the system.The capacitor blew up and that plastic burning smell was all over.

[RadiantSvgun]

Thanks for the help guys. I'll make sure not to turn it on, and when I send it back, I'll ask if they can install a cooling fan.

[Bratwurst]

How many times have you turned this game system on and a burning smell resulted? More than once is too many times.

[RadiantSvgun]

2 times. Once when it first started, the second after I tried the method of letting it sit for hours.

[SnowKitty]

I highly doubt they were being lazy. I might have just had some bad luck with this unit. But that burning smell is the sound capacitors?

i wouldn't know. the only way to really find out what the burning smell came from is to open it up.

[Bratwurst]

2 times. Once when it first started, the second after I tried the method of letting it sit for hours.

In the future, don't do that! Burning smells and electronics just don't bode well. There's no magical elf that makes them go away on their own, and believe me I have looked for that tiny man.

[omnedon]

Radiant has contacted me via e-mail. Now that the weekend is over and we are open again, I have responded with instructions for return for free warranty repair.

ooXxXoo:

""It is almost for sure that your problem is the sound capacitor.This is a very common issue with the Turbo Duo's.It can be easily fix simply by replacing it.The problem itself relies with the location of this capacitor,it is very close to the IC regulator Heatsink and it can fried with the heat that the regulator provides after a while of playing.NEC decided to put in there dry capacitors.There is a replacement tutorial somewhere,but you going to have to google around.I don't remember where it is.""

This is almost correct, or at least partially right. Contrary to online tutorials, there is not one single capacitor that always fails. Usually it is one to three failed or failing capacitors. Which three it is, is the real trick, as each DUO seems a little different. Some can be fixed by following the tutorial, others require more or completely different parts of the circuit replaced. Also, sometimes there are caps that are 'likely' to fail, so it is a good idea to replace them as well. In this DUO's case, according to the notes in my tracking database, most of the audio circuit caps were replaced, and few other 'visibly leaking' were also replaced for reasons of future reliability.

After servicing (and region modding) Radiant's DUO, it was stress tested with disc games and HuCards for a cumulative 6 hours, 3 of those consecutive testing the repaired audio circuit. It passed all of these tests with no audio or heat issues, prior to shipping.

Obviously, the problem seems to have returned. I've already given Radiant return shipping instructions, and plan on repairing it (and returning it) at no cost to him. I have however asked for more time this time, so I can stress test the unit for longer periods of time, to ensure no further inconvenience on his part.

I've personally repaired more than 200 DUO's. This is the very first recurrence of audio failure I've seen. Obviously, something was missed, or something in the 15 year old hardware has decided to give up the ghost after the repair. Such are the risks of offering repair service for such old electronics. However, that is why we have a 3 month warranty (that we honour outside the 90 day period on occasions where it is reasonable to do so).

While I love this forum dearly, I do not like dealing with these sorts of issues in a public way, as frankly I believe dealing with the warranty issue is something between OSG and the customer. Once we've dealt with the issue (hopefully to the complete satisfaction of the customer), of course I expect the customer to tell others for good or for bad. That's why every effort will be made to solve this issue to Radiant's complete satisfaction. My reputation (and livelihood) depend on that.

So, we can all opine on what the problem may be. If I run into a problem, I may even post and ask for informed opinions on solutions. However, please reserve judgement on quality of service until OSG has had a chance to conclude the transaction.

And this transaction is not concluded until every effort has been made to solve Radiant's issue to his complete satisfaction, with my apologies for his inconvenience.

[FABombjoy]

From another member that ocassionally sells refurbished & modded hardware, that was very well put.

It's all old hardware, and sometimes shit happens. Who knows what kind of life that Duo had before it was serviced. Same goes for any piece of hardware, like buying a used car made in 1992.

When you sell & ship hundreds of old game systems, it's enevitable that at some point something will go wrong, be it a careless package handler, bad off the shelf parts, or NEC beancounters sourcing capacitors from some second-rate supplier.

[SnowKitty]

From another member that ocassionally sells refurbished & modded hardware, that was very well put.

It's all old hardware, and sometimes shit happens. Who knows what kind of life that Duo had before it was serviced. Same goes for any piece of hardware, like buying a used car made in 1992.

When you sell & ship hundreds of old game systems, it's enevitable that at some point something will go wrong, be it a careless package handler, bad off the shelf parts, or NEC beancounters sourcing capacitors from some second-rate supplier.
yup. im surprised that my duo is still all stock parts and working fine, though i will replace all the caps (not just the audio ones) once i get suitable replacements

[RadiantSvgun]

Thanks for the help in this forum guys, and FYI, I'm in no way saying anything negative about oldschoolgamer services. They are top-notch and I plan to use them for all my console services.

[MonoTekETeA]

With the failure of the capacitors being linked to how close they are to the heatsink and what not, would it work to not cut the capacitor short, place insolation over the wires, and have them bend away from the heatsink? I have yet to work on a duo, but I figure would this work out?

[omnedon]

With the failure of the capacitors being linked to how close they are to the heatsink and what not, would it work to not cut the capacitor short, place insolation over the wires, and have them bend away from the heatsink? I have yet to work on a duo, but I figure would this work out?

I see the proximity to the 'warm' heatsinks as secondary to the crap quality of the caps. There is not enough heat there to damage healthy caps, IMO. The heat doesn't help, but IMO crappy caps are the real issue. All over the board, including failed ones nowhere near the heatsinks.

[SnowKitty]

I see the proximity to the 'warm' heatsinks as secondary to the crap quality of the caps. There is not enough heat there to damage healthy caps, IMO. The heat doesn't help, but IMO crappy caps are the real issue. All over the board, including failed ones nowhere near the heatsinks.

this is true, supposedly there was a bad batch of caps going around back then. ive seen game gears have leaked caps (not just the sound ones) and ive seen some leaked caps in duos other than the ones near the heatsink

[omnedon]

It's back here now.

Indeed, the sound was gone, again. I took another look at the audio circuit, and the array of caps. I've replaced another batch of caps (10 more) and the sound is back. However, it's quirky. When the unit is cold, the redbook audio seems to need a 4- 8 second warmup for the sound to reach correct volume and fidelity. Once reached, it seems stable, but this 'warmup period' is still annoying me.

I'm beginning to question the op amp itself, as most of the audio related caps are now new.

As far as the burning smell described, there is no evidence of any short circuits, or melted anything. Everything is as shipped, except for the quirky audio. I'm not sure what to make of that. The region mod works perfectly (and is making troubleshooting so much fun with this mod already installed =) ).


I'm stress testing the longevity of the audio now.

[XYXZYZ]

Speaking of the opamp, is that a common one? Is it hard to find a replacement?

[FABombjoy]

Indeed, the sound was gone, again. I took another look at the audio circuit, and the array of caps. I've replaced another batch of caps (10 more) and the sound is back. However, it's quirky. When the unit is cold, the redbook audio seems to need a 4- 8 second warmup for the sound to reach correct volume and fidelity. Once reached, it seems stable, but this 'warmup period' is still annoying me.
Figure it out, will ya? I've got one that does that too, but all audio (not just CD). Haven't had a ton of time recently to fully diagnose it. The lack of schematics doesn't help... I tried to draw up the audio circuit but my eyeballs almost fell out.

One interesting quirk - originally it was the opposite. 8 seconds of audio followed by silence. If I shorted the input/output leads on that balance control IC (the standy-uppy guy to the right of the op-amp), audio would come back for a split second.

Somewhat related trivia: I measured some of the OEM caps from a recent Duo that I worked on. Most of them still read the correct capacitance, but had really really high ESR.

[omnedon]

This DUO hates me. I hate it.

However, I am the BOSS, and I will demonstrate this fact to this DUO.....

[RadiantSvgun]

Hmm, so its the unit itself that sucks. How about that? I should have invested in a Duo-RX instead.

If it gives you too much trouble, hit it with a hammer.

[FABombjoy]

However, I am the BOSS, and I will demonstrate this fact to this DUO.....
Well, I don't know if you ended up giving your duo the Tony Danza, but... uh... anyway

So, I got mine to work. Chances of it being the same problem are slim-ish, but FWIW, ensure that you have ~3.6V at the + side of C322 (3 caps to the left of the OKI chip). Turns out that on my Duo, C322 had leaked just a little bit and corroded the through-hole for R321. I cleaned it up and fixed it with a bit of wire. Good as new!

How I got there: I was probing my way back through the audio circuit with a logic pulser (makes a nice test-tone for the audio hardware) when I discovered that feeding a square wave into C322 turned the audio on.

[omnedon]

Thanks for that. I have a few stubborn boards here, and I'll look into that.

Radiant ended up getting a whole new mainboard, region modded again. Yikes. However, taking care of his problem was a higher priority than making sure I didn't lose on the deal. I can use boards like his for R&D, which helps out in the end.

Problems teach as much as successes do, sometimes even more.

[turbokon]

Mine had a similar problem. I was playing Lords of Thunder fine one day. Later that day, I thought I will play LOT again and my sound was static and would fade in and out randomly. I notices a terrible smell (not burning smell) but terrible. I opened my Duo and I could see which cap was bad. I replaced it. My sound came back and I left it on for two hours just to make sure no other caps needed to be replace and eventually the smell went away (due left over electolyte).

BTW, I'm starting to offer this type of service to. My post went a away because I'm a newbie, but you can find this post at http://www.pcenginefx.com/forums/index.php?topic=4953.0. I'm working on three units now, two include the sound fix.

[omnedon]

Turbokon, was it one of the regular silver surface mount caps, or was it one of the other ones?

[turbokon]

yeah, it was the third one down on the pre amp side, 22uf.

[omnedon]

No, on this DUO, I replaced that cap. And EVERY other surface mount cap on the board, with no change.

Now I've seen another with the same issue (all caps replaced, audio still bad). I solved the customers problems by replacing their mainboards altogether. Now these boards are for R&D.

The cap replace fix does not always work. It does a lot of the time, but not always.

[FABombjoy]

$25 to replace Duo caps AND ship the unit back? By the time it's all done and said, that's gotta be less than making minimum wage.

[omnedon]

Indeed, that is one hell of a price. He's out on his very own pricing tier.