REPAIR GUIDE - TurboDuo: Sound Fix

[D-Lite]

Yes, you read that right!!

Note that this is a fix for a SPECIFIC sound issue, but the big one.  For this to work you will need to PROPERLY identify the problem with your system.  There is more than one problem that can occur with Turbo Duo systems and I think this is going to work for many.

OK, the problem and diagnosis.  Here are typical issues with Duo systems:
1.  CD plays and loads fine, but all redbook audio (soundtrack, not sound effects) is dead.
2.  audio is scratchy and may fade in and out, but the CD games load and play no problem (well, except for sound, duh)
3.  CD play is sketchy and the drive sounds like it's struggling.  More than just a sound issue

This fix seems to work mainly for the #2 case and maybe for #1.  I need to test more systems though to be clear on what it works on.  It should work for both, but I won't commit to that without further study.

So, some of you may have seen my hypothesis about what the sound issue is due to and after struggling for a way to prove it, I've finally found a way to study it.  I blame the sound issue on overheating with the Duo model and have stated that the later DuoR and RX should be problem free due to placement of the audio components in relation to the heat sinks.  But how to study the problem when you need the CD drive running, yet the cover off?  The CD lid is required to keep the CD spinning.

At this point I'd like to take a moment to mourn the loss of a PC Engine Duo that gave it's life so others may live:

_{https://www.multimods.com/images/Sales/R10x600.jpg}

I cut the top up so I could test the components while running.  Don't worry, the unit itself was already dead anyways. 

OK, so, look at the area need the heat sinks:

_{https://www.multimods.com/images/Sales/R9x600.jpg}
In the yellow circle I highlight key components.  The 10 uF caps on the left and right are controlling the left and right channel pre and post amp.  The little 8-pin chip in the middle is an op-amp that is needed to process the sound.  After tapping around on these, I found that the POST op-amp caps are indeed the ones responsible for the sound level and the scratching you sometimes hear.  Sweet!  These come from an era in the early 90's when there was rumored to be a problem with capacitor production.  Dry cap likely.  This is the same issue as with the Turbo Express that I covered before.

So then I ripped the bastards out and soldered down a couple of brand new 10 uF, 50V caps:

_{http://www.multimods.com/images/Sales/R12x600.jpg}

Simple as hell and cheap, <$1 for the parts.  Of course you need a special screwdriver bit to even open the thing, but hey....

And that's that!  As said, I'm still working on what can and can't be repaired with this problem.  More details will come when I can figure that out too.

And as it turns out I am figuring out how to deal with problem #3, wonky CD drive performance.  Hallmark is the grinding, whining, whistling, stopping, grunting CD drive and game pausing, slow loading.  There are 5 little screws in the unit that directly effect the drive performance so hopefully that will be fruitful.

Major thanks to Saibot and monads for supplying Duo's to look at.  Hopefully I can fix theirs too.

[rolins]

Excellent work D-Lite! When will you be able to take orders?

[esteban]

Absolutely fabulous work, D-Lite! And the presentation of your post, including the photos, was simply killer. THANK YOU

[larsulrik]

Awesome!  #2 is me (even though I mentioned a couple of weeks ago letting it run for a while temporarily fixed it).  Do you think the overheating will still be an issue with the new caps or was that just something the old caps had problems with?  Thanks Chief!

[dj898]

good to see we still have PC Engine/Turbo gurus around...

[D-Lite]

Awesome!  #2 is me (even though I mentioned a couple of weeks ago letting it run for a while temporarily fixed it).  Do you think the overheating will still be an issue with the new caps or was that just something the old caps had problems with?  Thanks Chief!

I think the main issue is the old caps suck.  I've seen beautiful Duo's have the sound problem.  I've seen MANY Turbo Expresses with dead caps too.  The problem is likely due to the quality of the capacitors themselves so the new ones will probably be more robust for longer times.  

I have a couple systems on hand that have flakey sound.  Sometimes I run it for 2 hours straight and no problems!  Sometimes it's screwed from the start.  Hard to figure out the problems when it's like that, like your system that gets better with running.  Perhaps something causes it to build enough of a charge that it'll work, who knows.  The good thing is, doing this little repair can only help, not hurt.

[TurboHuC6280]

Nice work!

[DragonmasterDan]

Though I dont have a problem with the sound on my Duo, would this be a good thing to do for preventative maintanence?

[esteban]

Though I dont have a problem with the sound on my Duo, would this be a good thing to do for preventative maintanence?

Ahhh, good question, Dan.

[Keranu]

Well done again, D-Lite.

[D-Lite]

Though I dont have a problem with the sound on my Duo, would this be a good thing to do for preventative maintanence?

Ahhh, good question, Dan.

Not necessarily good or bad.  It's simple enough so sure you could, but I'd wait until the problems start.

I've been testing out a system that has no volume at the start and then comes in within 15-20 seconds of play and persists well.  Again seems to be a capacitor that is poorly charging.  This will/should address #1 above, I hope, to some extent.  I have another Duo here that is highly unpredictable in terms of #1, so that is my big challenge.

[CrackTiger]

Though I dont have a problem with the sound on my Duo, would this be a good thing to do for preventative maintanence?

Ahhh, good question, Dan.

Not necessarily good or bad.  It's simple enough so sure you could, but I'd wait until the problems start.

I've been testing out a system that has no volume at the start and then comes in within 15-20 seconds of play and persists well.  Again seems to be a capacitor that is poorly charging.  This will/should address #1 above, I hope, to some extent.  I have another Duo here that is highly unpredictable in terms of #1, so that is my big challenge.

I'm so glad that there are people like you that not only have the know how, but also give a damn about a system like the TG/PCE to do things like this.

[grendelrt]

I know I am reviving a dead thread, but I think this a good thread to keep at the top.

I was wondering a couple things. This will be my first undertaking of modding a system. I was wondering the best way to remove the original capacitors? Also I noticed D Lite replaced a third capacitor at the bottom (not one of the two he pointed out), does it need to replaced as well. What wattage soldering iron should I use (specific solder?)? Right now my duo every once in a while has the sound fade in about 20 secs after start up and some scratchy audio issues, both of which it seems this little mod will help. Any other suggestions would be appreciated.

[grahf]

grendelrt, try some fresh desoldering braid and a good fine tip iron. A touch of flux may help if the braid has trouble getting started. It may be a tight fit to get to some of the caps. Then when youve got them pretty clean, just heat and lift each side lightly alternatly until it comes off.

[grendelrt]

Cool thanks =)

[Seldane]

15-25W.

[grendelrt]

I am going to try and grab an old computer motherboard and test out my skills on it first. The last thing I soldered was not a precision job  

[grendelrt]

Well the only thing i could find at the local radio shack was a 10uf 35v. DO you think this is enough ? The capacitors on the board are labeled 10 16. So I am guessing 10uf 16v. D Lite said 50V for his replacement, but I am not sure of anywhere else to find a capacitor locally. By the way, this things are soooo much tinier than they look in the pics lol

Well I finished, I used the 35v caps and they seem to be working fine. I had no fade in music with Lords of Thunder, which almost always happened. I tried to take pictures along the way to help others, but they didn't come out, the only one that is half decent was the final product pic:



Oh and here is a video for your enjoyment and my moment of happiness =)

s63.photobucket.com/albums/h152/grendelrt/?action=view¤t=pic017avi.flv

[bgarske]

Wow! That's cool. Now I wonder if I have the same problem. I lose the music usually late into a level on Lords of Thunder. (Certain levels more than others.) I thought it was because my disk was all scratched up. I've not had any problems with Gate of Thunder losing the CD music.
  So far, those are the only Duo games I have with CD audio. I'll be getting some more CD games (and a new copy of LOT from tzd.com) real soon so I have some more to test with. What do you think? Am I going to have to do surgery?

[grahf]

Nice job grendelrt. Yes, those caps you used will be fine. Its ok to go with a higher voltage than required, but no need to go overkill.

bgarske, I would wait until you get your new copy of LOT before you do anything. The way most Duos are, if you make them skip bad enough they will stop playing audio until its ready to load the next track. If you tap the console pretty hard for example. If you disk is scratched bad enough, it could possibly be causing the same thing.

[grendelrt]

Yeah grahf is right. I was moving my console the other day and bonked it, CD cut out because it made the CD skip. If the scratches on your disk are bad they could do the same thing, from what i hear the CD Roms all have pretty crappy error correction.

[bgarske]

Hey grendelrt, what did you use to open the case?

[grendelrt]

I bought one of those security bits of ebay, was like 6 bucks shipped. Here ya go:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=8275116257

[SignOfZeta]

This is very good news for people with OG Duo sound problems. I seem to be the one guy on Earth with an Oct 1992 Duo and not a problem.

I feel like I have to point out though that a Duo can be run with the case off totally while servicing it. The magnet in the lid can be removed amazingly easily, and the placed on top of the CD to hold it in place as usual. No need to destroy a good case.

[esteban]

This is very good news for people with OG Duo sound problems. I seem to be the one guy on Earth with an Oct 1992 Duo and not a problem.

No, there are many of us who have had no problems. I have a TG-CD and TurboDuo and haven't had a problem with them. The TG-CD has had a billion hours of use and is still going strong. When not playing games, I used to listen to music CD's for hours on end. Had I thought about the long-term, I would've used another CD player for music... but it never ocurred to me back in the day.

[grahf]

A large number of electronics from the early 90s/late 80s have the capacitor problem. Its not just NEC consoles. I do a lot of work on automotive ECUs/ECMs. Some will always need replacing, but in other cars they will always still be good.

I think it has a lot to do with where/when the console was made, and which components were used. Some consoles are just going to go bad, its only a matter of time. Others will last like they were supposed to.

[Keranu]

Good info, grahf.

[geise]

So this fix still only works for problem #2, the sound that fades in and out.  So no one has gotten this to work with problem #1 yet?

[bgarske]

I got my new Lords of Thunder disk in and it works perfect! (The music doesn't drop out like the other scratched up disk.) It must have been the disk that was the problem. So it looks like I have an America Turboduo without any problems!

[avkooi]

Since a few days, I am the proud owner of a Duo RX, which (sadly) has the same problem #2 as described by D-Lite.

I opened the console and found out that the identification numbers (C???, IC???) are the same ones as on the pictures from the Turbo Duo mainboard.

Do you think it helps if I change the two capacitors (C604 and C610) for new ones? BTW, they are not located close to the power circuit, but under the optical unit, and the capacitors are not the metal ones, but look like the ones D-Lite used for the fix.

Any help is much appriciated!

[grendelrt]

This is one of the first times I have heard of the RX having sound problems, they are usually problem free.

[grahf]

Its still possible that they are bad, even though they are not the usual faulty type. It cant hurt to change them if you have the ability.

[avkooi]

I changed the two capacitors "after" the op-amp, like D-Lite wrote. The problem of the fading sound-level is over now. But there is still a lot of electrical noise from the audio-out. It sounds like a bad contact, but that can not be the problem, because I checked and cleaned them.

So my next plan is to change the capacitors on the pre-amp side as well. I'll let you know what the effect will be!

[grendelrt]

Sounds good, I was thinking of changing those out myself.

[JoshTurboTrollX]

I hate to necropost but I have a story.

I have a Duo(US) that seems to have (or had) the #2 problem.  The games load up just fine, but the CD music/sounds don't work at all.  I had even tried using just a regular compact disk.  I think it was an amorphis CD to be exact. And on the Music player it shows that the CD is playing, but I still would get no sound.

This was around last summer(2005) when I was just getting totally frustrated with this!  In 2003 I had a DUO totally blow out on me, it wouldn't even spin the CD.  So instead of going out and seeking my 3rd Duo, I decided on emulating.  Now while I love what they'v done with ME and HUGO, It just isn't the same.

So I was telling one of my buds about some of the problems I've had with the DUO and just last night, say around 8pm we  got together and I pulled out the ole DUO from storage and booted it up.  I put in Lords of Thunder, and boom, NO sound.  the built in sound effects where ok, and the game was playing just fine.  

Then just for the hell of it we played around with some HuCards (BattleRoyal, Bomberman, and Sonic Spike)  after about 2 hours of gaming a couple more people came over, and they were asking about some CD and SCD games, and I regretfully told them that the Duo lense had burned out.  SO just for the hell of it I tried Lords of Thunder again and when I hit Run, all of the SUDDEN the most rockin' soundtrack EVAR in a video game came thrashing out my Surround Sound!!!!

My friends told me I looked like I saw a ghost.  I was in shock, the friggin thing was WORKING!!  We went on to play Dungeon Explorer II, Fatul Fury Special, DracX, and Lords until around 5am!

Every single game worked like a charm!  I cannot explain it. Then I read this:

I let it run for a while and this seems to fix the problem.

Holy CRAP!!! So does anyone else have issues like this?  Where you can just let it 'warm up' and then it runs well?


So I'm going on about 2 hours of sleep, and while my wife is at the store, you guessed it I'm playing some more DUO..\

LONG LIVE THE DUO!!!!!

Now with the above problems I posted above-(The #2 Problem) will the solution that D-lite posted fix that if it gets worse?  Or should I go with the other fix that I saw in another thread about replacing the lense?


TurboSage

[guyjin]

The duo has 1337 self-healing skillz...  

[grahf]

turbo_sage, replacing the caps should fix it completely. Sometimes bad capacitors will start to work a little if you let them "warm up". For example on most of the TurboExpress and GT portables with the low sound issue, if you play for a while the sound level will gradually rise.

Unfortunatly its just common for capacitors that were manufactured during that era to be notoriously bad. Not just NEC consoles, but a LOT of other electronics (many many automotive ECUs for example).

[Platinumfungi]

I realize this topic has not been active in quite awhile but I have the exact same audio issue with my Duo R.  I have located caps C604 and C610 for replacement but I am not sure which other caps relate to the audio.  If anyone can give me any input I'd really appreciate it.  I can send a digital pic if needed.  (or post the pic if someone can tell me how to)

[PCEngineHell]

If you feel completely up to it,when in doubt replace all old caps on the pcb. Good japanese caps manufactured these days are much more solid then the ones from early 90ies. Its more of a shotgun method but if the problem can be fixed by replacing the caps then replacing all of them is a sure fix,and in the process your buying your system more life with newer caps.

[Platinumfungi]

True.  I might just do that if replacing the two caps doesn't fix it completely.  Is there any company/brand of caps that are of higher quality then others?  I just bought mine at Radio Shack but if there are better ones then I'd gladly buy those.

[PCEngineHell]

The Radioshack ones are fine overall in quality. I never ran across a defective one when purchasing from there. But I tend to only buy 220uf caps there for Genesis s-video mods.

http://www.partsexpress.com/webpage.cfm?WebPage_ID=329

I think most of the caps they sell are manufactured by Xicon which is supposed to be reliable. As far as japanese caps go,you will know if they are made in Japan,they usually say Japan on them. Panasonic has a line of caps they sell under the TK series. They tend to be surface mount and are very reliable. I don't know if they will cover everything you need but I'm sure you can find them on Digikey somewhere.

[Platinumfungi]

Excellent. Thanks for the info!

[PCEngineHell]

Let us know if it fixes your problem.

[raven1280]

I bought a duo from GUITARMAS that had the sound issues. I had to end up replacing all the caps on the board. Alot of them had leaked. Wasnt to hard to do. Now I have great audio from the cds!

Raven

[grahf]

Its good to know people are taking the time to fix their Duos. Nice work.

[raven1280]

From what I can tell from my repair work theres another capacitor thats responsible for the audio coming from the cd. If you are looking at the board from the back by the power supply to the left there are two capacitors. One is 22uF 16v and the other is 47uF 6v. The 22uF is the one that is part of the audio capacitors. Im at work right now so I cant post any pictures.

Raven

[Tatsujin]

2.  audio is scratchy and may fade in and out, but the CD games load and play no problem (well, except for sound, duh)

i bought a DUO today and it shows exactly that issue as described above from you. i hate it, because i still can bring it back within a week but also need to go there again which takes 1 hour for one way. but the fix with the capacitors isn't a big issue for me anyway.

thanx a lot d-lite.

the sound via earphones is proper even i think the FX are a little bit to weak. does someone know that problem as well?

[Duo_R]

Whatup Turbo Community! I just wanted to let you know that I followed this process and my Duo's sound now works! I have found the specific cap that fixed my CD sound. I will post more later.

D-Lite - How is it going buddy? Long time no talk!


Erik AKA Duo_R

http://www.geocities.com/duo_r@sbcglobal.net/

[astrodan88]

Hi all,
I'm hoping someone could offer a little help. I recently acquired a Duo that is having sound problems. It's essentially what D-lite described as problem #1 (plays fine but no redbook audio from CDs). I just completed the mod D-lite described (replacing the 2 post-amp caps) hoping it would also solve my problem but unfortunately the audio is still gone. Someone else mentioned other capacitors relating to the CD audio. Has anyone else had this problem? Does anyone else know other caps to replace? Any assistance would be appreciated.
Thanks in advance!
astrodan

[nat]

Astro Dan '88!!! For Astro Dan, the year is always 1988.