REPAIR GUIDE - TurboDuo: Sound Fix

[Ceti Alpha]

The Duo lives! Another one saved from the scrapheap.

Woot! Well done nat! 

While I was in there I also adjusted the laser which has been giving me the singing treatment lately (no gameplay problems yet, but I hear the singing isn't a good sign). I adjusted 90 degrees counterclockwise and she purrs like a kitten again.

What's this "singing" sound like? I'm guessing it doesn't sound as pretty as the term suggests. 

Good to hear that you got her back to five by five.  I really need to crack mine open and resolder the a/v port, as I'm getting mighty tired of wiggling the damn cable.  Why, oh why did those cheap bastards do such a crappy job on that thing?

I agree.  To make one of the most sleek and beautiful console designs ever, but go cheap on some key things just doesn't make sense. I guess that's why we got so many freebies with the system when it came out. lol 

[nat]

While I was in there I also adjusted the laser which has been giving me the singing treatment lately (no gameplay problems yet, but I hear the singing isn't a good sign). I adjusted 90 degrees counterclockwise and she purrs like a kitten again.

What's this "singing" sound like? I'm guessing it doesn't sound as pretty as the term suggests. 

It doesn't sound as bad as you're probably thinking. It's a very high pitched (but quiet) consistent "whine" whenever the CD-ROM is active. The whine comes from the laser itself, not the speakers. It's easily ignorable, but apparently the general feeling is a laser emitting this tone is headed south and needs to be tuned. Ignoring this warning sign apparently often ends in a dead laser.

[Ravij]

Hi - I just tried changing the two 10 uF Caps (post op-amp), but it didn't fix my issue. The problem I have is that there's no (or very quiet) CD Audio for the first 3 or 4 mins that the Duo is turned on. Then all of a sudden it will work fine and keep working, so it isn't a major problem, but definitely one I'd like to fix!

Anyone had a similar issue and found which caps to change? I realise I could just change the lot, but I'm not sure I have the willpower to change more than a couple at a time!

[Ceti Alpha]

The problem I have is that there's no (or very quiet) CD Audio for the first 3 or 4 mins that the Duo is turned on. Then all of a sudden it will work fine and keep working, so it isn't a major problem, but definitely one I'd like to fix!

That's exactly how my audio issue started. When I first got my Duo there would be no sound (or very quiet like you said) for the first few minutes, and then would kick in after 5 minutes give or take. Your audio may never get any worse, but I'm guessing it will. In any case, it's thankfully not a big deal and totally fixable. 

[Ravij]

it's thankfully not a big deal and totally fixable. 

Did you fix it yourself? If you know what caps got changed, that would be very helpful!

thanks,
Ravi

[Ceti Alpha]

Did you fix it yourself? If you know what caps got changed, that would be very helpful!

Unfortunately not - I sent my Duo to D-Lite to get fixed. I'm getting it modded as well, so there was really no point in trying fix the audio issue myself. But I'm sure someone here will be able to help you more.  Sorry I couldn't be more help. I know all too well how frustrating the sound issue is.

[Alt-Nintega]

Oh damn. I just bought a black Japanese PC Engine Duo from ebay last night. I hope my system works fine. 

[CkRtech]

This thread has been a great resource. Thank you to all that contributed. It made repairing the sound issues with my Duo seem like child's play.

For the record, I replace the main caps mentioned in the images earlier in the page, but those weren't enough. As a general rule of thumb, it is probably a good idea to replace all your caps in that amp area - this has been mentioned before, but I just wanted to repeat it. That said, I'll give you the extra details on my issue.

I was experiencing somewhat crackling audio of the CD playback during the first minute or two of gameplay. It would clear up after that & seem just fine. In addition to the caps mentioned earlier in this page, I replace four other caps:

100 uf 10V
220 uf 16V
470 uf 16V
1000 uf 16V

Each were replaced with Radio Shack caps (I believe they're all 35V). The early crackle went away, and it seems like I had a much wider frequency range of playback (i.e. bass was much clearer). I have marked those caps on the "cap map." I hope those that created this image don't mind my modification:

[nat]

That's curious about the 1000uf cap needing to be replaced. That type of cap isn't prone to leakage or failure.... Are you sure it was necessary in your case, or were you just covering all your bases?

Speaking of the sound issues, I recently discovered a cap elsewhere on the mainboard outside of the op-amp cluster is directly linked to certain sound issues. Specifically, if you are having problems with all of the following: ADPCM sample playback, PSG, and redbook. The cap in question wasn't previously known to be part of the audio circuit at all and I have a feeling is the culprit in the cases where replacing all that caps in that circled area and to the right of the circled area don't fix the problem.

You have to remove the FCC shielding to even see this cap. It's kind of in the middle of the board, out in no man's land by itself. Like the component I discovered to be responsible for video failure on the TurboExpress, this is another innocuous little guy you'd never suspect. I'll post a picture up in the next couple of days that shows where to find the little rascal.

[CkRtech]

Hey nat -

No. I just grabbed all the caps in the area just to be on the safe side. The only ones Radio Shack didn't carry were the 330uf (x 2) that are not labeled in the picture.
....plus I just got a new soldering station & was dying to try it out. 

[Duo_R]

Anyone have the other cap values mapped out on the board? My good fortune didn't last forever, the sound eventually went out again. I looked at the other caps on the board today and noticed some that didn't look good. However, I am very confused with some of these values:

22
6a
25m

100
6s
25a

I take it that these are 22uf and 100uf caps, but what the hell do the the other codes mean? What is the voltage for these? I have a personal friend who is a electrical engineer and warned me about going too high on the voltages of the caps that I replace with so I wanted to match these up.

[Duo_R]

never mind - I found the full list of specs for the caps. Update - I replaced some more and now my Duo seams to be doing better (for the moment). After about 30 second warmup the sound is decent. There is a little scratchy fade in sometimes, but the longer the system is on the better (so suspicious that there is another bad cap). I placed an order for some more caps, so will just keep replacing...but I installed a Blue LED!!!

[Duo_R]

Any updates on that cap?

That's curious about the 1000uf cap needing to be replaced. That type of cap isn't prone to leakage or failure.... Are you sure it was necessary in your case, or were you just covering all your bases?

Speaking of the sound issues, I recently discovered a cap elsewhere on the mainboard outside of the op-amp cluster is directly linked to certain sound issues. Specifically, if you are having problems with all of the following: ADPCM sample playback, PSG, and redbook. The cap in question wasn't previously known to be part of the audio circuit at all and I have a feeling is the culprit in the cases where replacing all that caps in that circled area and to the right of the circled area don't fix the problem.

You have to remove the FCC shielding to even see this cap. It's kind of in the middle of the board, out in no man's land by itself. Like the component I discovered to be responsible for video failure on the TurboExpress, this is another innocuous little guy you'd never suspect. I'll post a picture up in the next couple of days that shows where to find the little rascal.

[Redfield1]

Thanks for the great job.

My Duo got the audio tracks back.

nsa02.casimages.com/img/2008/09/04/08090405262578430.jpg

   ... Red ...

[Duo_R]

Update - how is the sound fix working? I am nearing full replacement of the entire caps. I got full sound, but an intermittent scratch sound. Funny thing is the scratch get's better and better, then I replace another cap and it gets worse. We will see how things go after full replacement.

 

[oldschoolgamer1989]

Will 10 uf 35 v caps work?

[Duo_R]

that diagram he has is showing the cap values he used, but 10uf 35v would work fine. The value of the caps could be between 10uf 16v - 10uf 35v (i personally wouldn't go higher).

[oldschoolgamer1989]

Thanks for the tip!!

[oldschoolgamer1989]

Replaced the first 2 caps today and still no music. Which ones should i look at next?

[oldschoolgamer1989]

Just a note: After leaving the unit on for about 10-15 mins. The music finally starts playing. what next?

[Duo_R]

BREAKING NEWS EVERYONE: THE LARGE CAPS CAN GO BAD!!!

Take a look at what I found today (note - you can see the leaking marks on these little bastards):

/downsized0918081951bjw9.jpg

This was the 1000uf 16v, and the 470uf 16v (the one that was next to the 1000uf). The 470uf was fine the other side of the heatshields, but I replaced anyways. These caps are so close to the heat sinks I should have suspected. Instead some said they weren't usually a problem so I didn't bother. Now the replacements - the original caps are rated up to 85 degrees Celsius, but everything I am replacing with is up to 105 degrees Celsius (that's 221 Fahrenheit , so my Duo would be melting before these suckers break down).

Update on sound issue - the scratch sound is very minimized, and doesn't happen very much now. Maybe like a little sound every few minutes. I am going to check a few more caps. The only caps I haven't replaced in the sound (pre and post amp) area is two 330 caps. I am also going to check the 470uf cap near the power switch (although it might not be related to sound). Everything is a suspect at this point....

Oldschool - after replacing a sound cap I too noticed no sound (it is usually for like a minute or two) then the sound comes on. If it only happens once and then it is fine, it was just the cap charging (they are empty). Now if it still fades in and out, then you still have a bad sound cap somewhere.

[oldschoolgamer1989]

Thanks again! I'll run it again and see what happens. If it still fails, which ones do i need to replace and with what value? I'll need the uf and v ratings for each so i'll know what to pick up.

[Duo_R]

the bigger caps are marked with V, the smaller ones just use between 16-35v

/pcengineduototalcapreplsg8.th.jpg

[oldschoolgamer1989]

Is there a way u could point out the exact ones i should start with. Probably all the 10 uf 16 v right? and use 10 uf 16v-35v on all but which ones?

[Duo_R]

my suggestion is to replace almost everything in this picture:

/r9x600copyxo4.jpg

check the other diagram for the values of everything. All the radial style caps, including the 1000uf, the 330uf, the 470uf, etc. And the smaller SMD that are near the heatsinks. The two caps that are on the other side of the heatsinks were fine on my Duo, but I would still be suspicious because of how close they are to the heatsinks.

[markeggertsen]

Hey D-Lite --

Are you taking orders for Duo fixes? My Duo has virtually NO sound, but if you turn the volume on your TV all the way up, you can hear all the sound VERY faintly. It was working fine just a week ago!

Thanks!

markeggertsen@gmail.com

[Duo_R]

uhhh....dlite hasn't been on the boards for months. Long story.

[oldschoolgamer1989]

Thank you Duo_R!! You are the man! Changed all the ones you mentioned and the sound is back in full soon as it comes on. Everythings normal now. Also, special thanks to D-Lite for starting this post and leading us in the right direction. Without you guys, i don't think i would have ever figured this out.

[somery]

Hi everyone. I signed up for the pcengine-fx.com boards just to make this post. I wanted to thank everyone (especially d-lite, Duo-R and nat) for their hard work and many hours spent fiddling around inside their Turbo Duos. Because of their efforts, and this thread specifically, I've managed to fix the audio in my Turbo Duo all by my lonesome!

Now, I've played around with circuit-bending cheap Casio keyboards before, but that's all the experience with soldering I've ever had before now - and it was pretty shitty quality. (If I fried one, no big whoop. It was only a dollar at the thrift store!) However, when the sound in my Duo went out, I decided to get a little more serious because I was going to do this myself, dammit! I've never opened up a console before, let alone ripped out capacitors and soldered new ones in, so it was a little daunting at first. Nevertheless, I ordered the 4.5mm gamebit, hit up the local Radio Shack, rolled up my sleeves and got to work.

In the interest of science (heh) and to add, however insignificantly, to the general base of knowledge, here's how the whole thing went down. I should mention the circumstances. My Duo is a September 1992 model that I got off eBay (no, not from GameSquadStore!  ) a few months ago. It played beautifully up until last week when the sound went scratchy (ADPCM and CD audio) and eventually went out altogether.

I also feel I should mention, maybe just for myself, that I got the TG-CD for Christmas the year it first came out. Yeah, the one that was 400 freakin' dollars and came with a CD+G disc with Jimi Hendrix's "Purple Haze" and Little Feat's "Representing the Mambo" and maybe some other songs. (Incidentally, I never hear this CD+G disc mentioned on the interwebs.) God bless my mom for that. Anyway, I still have the TG16 itself (with stickers all over it), but have long since lost all the CD hardware.

ANYWAY......

Day 1: The gamebit finally came in (actually it only took three days to get here), so I went to Radio Shack and bought two 10uF capacitors, hoping that replacing the two "post op-amp" caps would do the trick. Performed the very first desoldering job of my life, put in the new caps, put the system back together and tried it. Nothing. I should note that neither of these caps had leaked. Cried myself to sleep. (Not really.)

Day 2a: Decided to go ahead and replace the three "pre amp" caps. Bought two 10uF and two 22uF caps (just to have an extra). Cracked her open again and replaced the three caps. This time, the original 22uF cap did have leaky electrolytic goop under it. I cleaned it up with some isopropyl alcohol before soldering the new one on. Put her back together and tried it. Now I had ADPCM sound, but no CD audio. At least now I knew I was doing something right.

Day 2b: Came back again to this very thread to see where to go now. Came upon Duo-R's post about the other 22uF cap that Raven had mentioned and decided to have a go at it since I had a spare 22uF cap. Lo and behold, it had leaked as well. Cleaned it up, replaced it, and crossed my fingers that it would do the trick. I really don't have enough confidence in my skills (or time) to perform a complete cap replacement, so it had to do the trick! It just had to, dammit! Well, the Turbo Gods smiled down upon me that night (last night, actually) because this time all of the sound worked. Crystal clear and kick ass! Of course, Lords of Thunder was the tester CD. 

So I just wanted to say thanks, guys. I've tried a bunch of other games on it since last night and it's still doing great. Thanks to this thread and the people in it, another Duo was saved from the scrap heap and I got a little console repair experience under my belt. Good show, everyone! 

[Duo_R]

Another Duo saved. If I could do it all over I would have done a cap removal, dishwashed the PCB, dry for 2 days, and then do cap replacement. Congrats!!! 

[MarsPants]

Hey! This is an awesome thread. I've wanted to fix my Turbo Duo for awhile now but I still can't seem to get some things in order. I've gotten most of the equipment but I'm still confused about the capacitors because I don't know much about them and I don't want to break anything. In Canada we don't have RadioShack anymore so it's a pain to find anything. Any info on what to get and how to get it would be awesome.

Also I would love to see someone who really knows this stuff to maybe put together a little step by step guide? This thread is such a great mine for information but it would be great to see it focused and cleaned into something easier to follow. Things like dis assembly, advice on what capacitors to start, and tips on the capacitor soldering. It's all here but I'm absolutely terrible at filling in blanks. I'm always so paranoid about doing something wrong, I'm sure plenty of people could relate. Maybe asking too much, but just an idea.

Anyway, any help would be very appreciated! I'm dieing to play with sound again.

[Duo_R]

Mars - I would do a guide but it is really straightforward. There is already a laser repair guide and that covers removing the case, etc.


http://www.robotpanic.com/?p=59


You will want to remove the metal sheild, desolder iron comes in handy. You will disconnect a wire from the power board, and the couple connectores near the laser and the screw that holds the ground wire. Remove about 4 screws holding the PCB, and then you can remove and work with just the board. This came in handy for me since I desoldered underneath the PCB to remove the caps. For surface mount caps I used a "lift technique" where I heated up one end of the SM cap and used a jewelers flathead to carefully lift up the cap. Then did the same on the other side. You remove the caps, and replace. Maybe a full guide later but if you read through this thread you will have all the information you need. I could understand more if this thing was 20 pages, but really it won't take you long to get what you need.

[MarsPants]

Thanks for the quick reply! These pictures are great, it gives me a little more idea what I'm doing. The info is good too, I'll have to practice some more before I try to pull it off though. Thanks!

[Duo_R]

find some old electronics that you can practice removing caps, and then replacing. You will want to get this down since you get 1 shot with your system. You want to be careful not to lift off the solder pad from the board (can happen if you try to just break a cap off, etc). I replaced about 50 caps on my Duo and it turned out to be just fine. I believe it really is only the pre/post amp caps you need to replace, but in my situation I had a scratch sound that wouldn't go away. Not knowing what was causing the intermittent sound issue I just get replacing caps. Nat eventually advised of a dishwash which took care of my scratch sound (and if you read the posts in this forum you will follow my progress). Now sound works, and absolutely no scratch sound (cutting in and out). I am certain that I had some cap residue screwing with my sound and that is now fixed.

[agt_dale_cooper]

That's curious about the 1000uf cap needing to be replaced. That type of cap isn't prone to leakage or failure.... Are you sure it was necessary in your case, or were you just covering all your bases?

Speaking of the sound issues, I recently discovered a cap elsewhere on the mainboard outside of the op-amp cluster is directly linked to certain sound issues. Specifically, if you are having problems with all of the following: ADPCM sample playback, PSG, and redbook. The cap in question wasn't previously known to be part of the audio circuit at all and I have a feeling is the culprit in the cases where replacing all that caps in that circled area and to the right of the circled area don't fix the problem.

You have to remove the FCC shielding to even see this cap. It's kind of in the middle of the board, out in no man's land by itself. Like the component I discovered to be responsible for video failure on the TurboExpress, this is another innocuous little guy you'd never suspect. I'll post a picture up in the next couple of days that shows where to find the little rascal.

Hello, Diane, agt_dale_cooper here, still waiting to hear the outcome of this post quoted above....meanwhile, enjoying some damn fine coffee here in Twin Peaks.  Waiting for caps to show up from Parts Express, mentioned by PC_ENGINE HELL in reply #40.  SUPER cheap caps, more than reasonable USPS shipping as well.  Bought a Japanese Turbo Duo from George on the Turbo List, NO audio output whatsoever.  Popped the top, C301 (1000uF, 16V) was obviously damaged/leaking, but no other apparent damage.  To date, have replaced C301 (1000uF, 16V, rated to 105'C., Fry's P/N 1005343, NTE VHT1000M16, $1.90) and C616 (22uF, 16V, rated to 105'C., Fry's P/N 1005493, NTE VHT22M16, $0.88), but have no audio-related love from the machine yet.  Have not bothered with pre/post op caps yet, decided to wait for Parts Express rather than pay Radio Shit $1.20/piece.  Will continue posting methodology and part numbers used, will also comment them on the Parts Express site.  Expense report forthcoming, Diane, not to worry!  Looking forward to Agt. Nat's posting...thanks!  [how come there's no coffee-drinking smiley?]

[agt_dale_cooper]

OK, success!  Caps finally showed up today from Parts Express, so I went to town on the thing.  First pull:  22uF, 16V at C323.  Result:  no audio love.  In looking to pull the next victim, noticed that there was an important difference between all the pics and my board:  C615 was MISSING!  (Duh, first rule of TG16 repair, insure all the shit is THERE!!!  Cap did NOT fall out when I opened it like reply 83, though, so it didn't occur to me to look..)  So, off I went to my bag-o-caps, only to discover that the 47uF, 16V was NOT a size I ordered.  Soooo, I threw in a 100uF, and lo and behold, some audio showed up, albeit very faint.  Encouraged, I replaced C604, C610, C614 and C613 as original post suggests, and WHAM! out rolls some nice Lords Of Thunder!!!  Woohoo!!!
Questions for anybody:  I've heard different types of audio terms being bandied about:  ADPCM, Redbook, etc....how do they all pertain here?  Is PCM generated by the game code / Redbook is pulled off CD?  Haven't I heard a third term used?
Haven't seen any ill effects from using the 100 as opposed to the 47....anybody tracing these circuits?  Are we gonna end up with LOUDER audio like Agt. Nat did using 47uF caps instead of 33uF caps in his TG16 Express audio fix?  Thoughts, anyone?  [Doesn't sound any different than my working USA Duo, but I suppose it's possible....may try altering the post op amps with higher uF units]
Methodology used:
1)  Pull caps using needlenose and back-and-forth rocking motion.  Don't really pull, you don't want to lift the pads these things are sitting on...just trying to snap the existing joint.  Also, there are fuses attached to the bottom of the board at these points, don't really want to use excess heat.
2)  Buy caps from Parts Express.  Pray that USPS delivers them quicker than they did mine.  Thanks again PCEH for a great supplier...much easier to look through than Mouser or Digi-Key, IMO.  Pictures are worth their weight in gold when replacing stuff.
3)  Prep pads by tinning, using flux pen beforehand if you've got one.
4)  Bend leads of caps into ][ style shape, where top is inside cap, length of vertical = length of horizontal foot.
5)  Tin ends of caps
6)  Use tweezers to hold cap in rough position, use end of soldering iron to link tinning on pads to tinning on caps.  If well tinned, should flow right together.

Bottom line, seems replacing C615 fixed the #1 case, no audio, as I'd only replaced C301, C616 and C323 before realizing C615 was missing, and got no audio out of replacing those three.  Got no audio?  Why not start with C615?  Perhaps this can act as a sight on the 'shotgun'....hee.

[Still waiting for Liar smiley #2 to be replaced by Hot Coffee Drinking Smiley...]
agt_dale_cooper

[Duo_R]

I would replace the 100 with a 47 although it shouldn't hurt. Just based ont the fact that the Turbo designers chose that cap for a reason. 47's aren't uncommon at all. Just pony up at RatShack, they always have that size (unless you have a reason to make another online order).

[agt_dale_cooper]

RRRRR....lost sound again, right back to where I started (CD sound is VERY VERY faint).  Gonna pull C615, replace with 47uF instead of the 100uF, HOPE that this 100uF has freaked out it's neighbors and they don't want to work anymore.  Will pull/replace all previously installed audio-related caps, hoping again that somebody has blown...makes a bit of sense, really, but I think I'm grasping at straws...we'll see, will post findings.

[agt_dale_cooper]

Wow, nothing.  Pulled all previously installed per Nat's suggestion (I too enjoy the notion of a clean slate...), reinstalled all to no avail.  Did the 47s up by the LED, did the 47 that somebody said isn't part of the audio circuit, C312.  Ran the thing with the top off, used eraser at end of pencil to manually shake all installed caps to test for crappy joints (in theory, this should sound porpoise up and down if you've got a crappy joint, right?)  Audio is there, it's just painfully faint.  HuCards work fine, in game button mashing sounds are there as well, it's just the CD audio.

Nat, where is this mystery capacitor mentioned a couple times by Erik and I?  Could this be my issue?  I was supposed to ship this thing today after installing region switch, and as luck would have it, audio has disappeared.....frigging switch install was easier than sorting this &^%^%$ audio issue!!!!!!  HAHAHA!!!

On a humorous note, the timestamp on my mod of that switch document says 04-19-03....been a while since I've done that mod, but it still works famously... (and yes, Twin Peaks STILL rules!)  For whatever it's worth, that document is directly applicable to the JAPANESE consoles, as the pins are simply a mirror image of one another...[not sure whether this Pin 29 business is required or not, but I did it anyway....reminded me of the PSX days...]

Anybody know how to test caps in the circuit / while the thing is powered?  A brief outline, if anybody does, might be helpful....gonna Google, see what it says, I've had it up to HERE with this (*&&^% audio issue.  I WILL fix this thing.

[agt_dale_cooper]

Wow, have spent literally ALL DAY trying to repair this thing.  Here's what I tried:
1)  switched lasers between my US and Jap units.  No dice, wouldn't read the CD, as wiring in middle connection isn't the same between the two, didn't feel like pulling and rewiring the pins.
2)  Pulled/installed fresh/tested caps all day, testing for both Redbook (CD Audio) and ADPCM (system generated snippets like the voice in Gate Of Thunder (J) ).  Installed fresh caps in all spots but:  C961, 962 (near power switch), C512, 515, 517, 519, 523 (above and near HuCard slot), C105, 110, 122, 133, 164, 200, 201, 202 (in between CDROM unit and front of machine).  All other caps I replaced, tested with GOT, got nowhere except severely irritated with the loud buzzing where the voice in GOT is supposed to be.  Sort of like having the buzzer from Family Feud go off like 3000 times today...
3)  Discovered that Pin 29 grounding for Japanese switch install is indeed required.  WSOD without it when trying to play USA games.  [tried pulling this, as it was the only thing that had electrically changed since I got the thing to play audio the other day....]

Now I'm literally out of caps, gonna get some more from PE...this project is HUNG for a couple of days while they're in transit, then.....urgh.

Next project is prolly gonna be to tear down my fully working USA Duo cap by cap, try to isolate what caps are responsible for which audio...pull cap, test, record comments, continue...that'll be fun too.

[blueraven]

  Crap. Well, the sound in my duo just went totally dead. It looks like i'll be posting my own follow up here in the near future.

[MarsPants]

Hey, it's me again! I started to replace the capacitors and I just finish replacing both the post amp. When I hooked everything back up the sound worked longer then usual but eventually went out. Also now the cd drive doesn't spin  . I was wondering if there is anything I could have done that would have caused this? The laser does move but the CD just does not spin. Any ideas would be great.

Okay never mind! I fiddled with the wires leading into the CD drive and it works again! It was a silly mistake I suppose.
However, any ideas what caps I should replace after the post amp? I'm assuming the pre amp so I think I'm going to try it now.

[Duo_R]

I went crazy after replacing all the post/pre amp caps and having sound but issue with intermittent static and sound volume issues (it was the shotgun approach). Nat predicted leaking cap fluid causing the issue and suggested a dishwash. I did the dishwash (you can get details on how I did it on another post) and after NO static issues. What was strange was initially my sound didn't come after the dishwash, but then after a few tests (it went in and out) it came on and never went out again. I did notice a 40% drop is sound output. It isn't a huge issue, but I have to turn the volume WAY up. I think I have a bad cap on there somewhere. If I were to do all over again here is what I would do with a  Duo with sound issues:


* Remove all the caps in the pre/post amp area (find the diagram on this website)
* Dishwash with the 7th generation soap Nat suggested - 1 cycle with soap, 2 cycles with warm/hot water (AND NO HEAT DRY, AIR DRY ONLY)
* Replace with new caps in the pre/post amp area

Why do I recommend this? Because some of the caps leaked and will limit wash/rinse underneath. Removing them ensures a 100% clean and you don't also run your brand new caps in the wash. I think it also helps the board dry faster. The way I did it was remove/replace caps then wash, but again I would do it in the order I listed above in the future. I just spent too much time monkeying around with the cap replacements, and I replaced all the caps thinking it was another issue before finding out about the dishwash method Nat suggested.

It was nice to fix the issue (but I need to get another cap replaced to get sound loud again), I debated on changing my username to DishwashDuo, but the Duo_R I purchased justified keeping that tag.

[agt_dale_cooper]

I learned something about capacitors today....
If your multimeter has a 'Diode Testing' function (symbol looks like ->|- on my Harbor Freight special), try this for testing caps in the circuit:
1)  Locate the Diode Testing function, switch to it.
2)  For post-op and pre-op caps (I'm using C604 as example here):  connect the positive lead of the MM to the positive side of the cap, connect the negative lead of the MM to the negative side of the cap, HOLD IN PLACE for like 30 seconds.  Readout will say "1", but hold in place for 30 seconds.
3)  Remove leads, switch MM to DCV = 20.
4)  Connect + lead to + cap, - lead to - cap
5)  Should observe values DECLINING...mine started at .35 for C604, declined as long as I held leads in place.

What's happening here is that the Diode Testing mode is actually supplying a small amount of charge to the capacitor, which it (if functional) absorbs....switching the MM to DCV = 20 (I selected 20 because it is closest to the 16V rating of the cap) and connecting actually allows the cap to DISCHARGE while you're measuring it!  Different caps on the board behave differently, but all the ones in the audio circuit appear to exhibit the same behavioral pattern.

This can be used to tell whether or not your caps are trashed, I think....might actually be used as a means of 'jump starting' caps as well....

Anybody that actually knows something about MM use / any non-layman-like-me type with useful knowledge have commentary?  [I'm reading while futzing about with my multimeter, DETERMINED to solve this audio issue.....I'm currently testing my working USA unit against non-working JAP unit, learning odd things along the way.  I think we've blown a resistor / fuse somewhere in the audio circuit, and I'm determined to find out WTF the bottom line is....]

Forgive me if you think I'm talking out of my ass, electricians, but this might help somebody....

[MarsPants]

Ahhh! It works  After a REALLY bad soldering job and about an hour trying to fix a huge blob of goo It works by some divine magic. All I did was replace the Pre and post amp and it did it for me. I can't say I'm completely in the clear yet because it seems that people post having problems after the fix. I usually could only play for about 2 minutes before sound malfunction, but I was just playing for about 30 minutes and no problem at all. Anyway, good times! This form rocks

[agt_dale_cooper]

Well, the PCE Duo hit the dishwasher this afternoon (went to Grandma's, made Chinese for dinner, threw the thing in while we were wrapping potstickers), it came out looking like reverse-engineered ass.  White funk all over the board, just like others have mentioned.  Bought some rubbing alcohol on the way home, hit it hard with the toothbrush, but even this leaves a white haze behind....

Question:  Is this haze harmful?  I doubt it (as it's no doubt non-conductive), but I need to throw it out there...

I'm gonna hit it again tomorrow (Black Friday ads look like reverse-engineered ass as well (but, CircusTitties have Arcade 360s with free refurbed 20GB HDD + wireless controllers for $199???  If these have Jaspers in them (with new onboard RAM), this may be a steal!  Pay close attention, though, if your local CT is slated for going under, they may not have all deals....these stores have actually been sold to a liquidation entity), retailers are gonna FLAIL with the economy in the state it's in) with the alcohol, then give it a good once over with the air compressor to speed the drying process...if my caps show up (again 'Parts Express' seems to be a misnomer.....nice folks, really (I called them the other day trying to replace C509 [which I believe to be the Tennokoe functionality], guy was super nice, even schooled me a bit!), but the shipping time SUCKS), I'll start soldering them on.  Yes, FUN FUN FUN, but it'll be better than being in with the maddening crowds at WallyWorld...

End of yet another exercise in insuring parentheses have been properly opened and closed/a post that looks like an Excel formula....heh.  More news to follow...enjoy your Friday, if you do that sort of thing....[throw an elbow or two for me  ]

[Duo_R]

AGT Dale,

I had some white haze stuck to the parts of the board that had excessive goo stuck to it. Did you run 2 washes with water only? Run 2 cycles water only (warm/hot water) with Air Dry. Then use mixture of 50/50 of rubbing alcohol / water with toothbrush on the board. That should remove most of the haze. It should look really clean after that. But mine was as yours was described. Then the most important piece is letting it dry for at least a couple of days. Setup the board in front of a box fan in your garage and just let the sucker dry out REALLY good. You don't want to risk something shorting out.

[agt_dale_cooper]

Well, got the thing back together after it's hot date with the dishwasher...

CD audio did NOT return, although ADPCM did (!!).  CD audio is still REALLY faint.  This rules out the M5205 (which I did find on eBay, BTW:  http://cgi.ebay.com/NEW-ICS-M5205-OKI-18-PINS-DIP-5205_W0QQitemZ150117198253QQcmdZViewItemQQptZBI_Electronic_Components?_trksid=p3286.m20.l1116 )

I had to pull it apart again to fix the power switch (seized up after I didn't dry it after removing from DW..), so once it's finished drying, I'll slap it all back together again, let it run overnight or something in hopes of charging caps or something....

Also helpful to note (for those of you with modded systems) that the CD player functionality works WITHOUT the HuCard slot connected...I installed a switch in this thing prior to it's audio failure, I just disconnected it from the HuCard slot and fired the thing up for CD testing....helpful not to have to wire up the switch back to the slot before testing!

[Duo_R]

I just left my 8PDT switch installed, and put it in a plastic baggy in hopes of keeping it from getting wet. The plan didn't work, if you try that use something that will really waterproof the switch. It wasn't harmful though, I just had to use a can of compressed air to get it dryed. I personally wouldn't remove your switch, that is just extra work.

[Duo_R]

just an FYI - I have a hunch someone is trying to make money off this guide. Oh well I guess everyone tries to cash in on ebay. 

http://cgi.ebay.com/TURBO-GRAFX-EXPRESS-SOUND-FIX-DO-IT-YOURSELF_W0QQitemZ150329742144QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item150329742144&_trksid=p3286.c0.m14&_trkparms=66%3A4%7C65%3A15%7C39%3A1%7C240%3A1318

Description    
DO YOU HAVE A VINTAGE TURBO GRAFX EXPRESS HAND HELD UNIT? IF SO, ONE OF THE COMMON PROBLEMS WITH IT IS THAT THE SOUND GOES OUT. IT WILL WORK THROUGH HEADPHONES, BUT THE SOUND DIES OR IS VERY LOW THROUGH THE SPEAKERS. DON'T SELL YOU SYSTEM BECAUSE OF THAT! ON THE OTHER HAND, THIS IS A GOOD OPPORTUNITY TO BUY ONE OF THESE SYSTEMS CHEAP AND FIX IT ON YOUR OWN FOR A HIGHER RESALE VALUE! I HAVE STEP BY STEP INSTRUCTIONS WITH PICTURES ON HOW TO FIX THIS PROBLEM! IT TAKES A SMALL SCREWDRIVER, A CAPACITOR THAT YOU CAN GET AT RADIO SHACK OR ANY ELECTRONICS HOUSE AND SOME SOLDER. I WILL IMMEDIATELY EMAIL YOU THE FILE UPON PAYMENT. YOU MUST HAVE MICROSOFT WORD TO OPEN THE DOCUMENT. PLEASE READ THE FOLLOWING, JUST SO EVERYONE UNDERSTANDS: I AM NOT THE AUTHOR OF THIS INFORMATION. I COMPILED THE INFORMATION AND PUT IT TOGETHER IN AN EASY TO FOLLOW FORMAT. THE INFORMATION WAS GATHERED FROM THE PUBLIC DOMAIN AND THE BEST/PROVEN INFORMATION WAS CHOSEN. THE SMALL FEE FOR THIS IS JUST FOR MY TIME AND EFFORTS TO PUT THIS TOGETHER AND MAKE IT CONVENIENT FOR YOU. I WILL NOT GET RICH FROM THIS INFORMATION! THANK YOU! SOON YOU WILL BE ENJOYING YOUR EXPRESS SYSTEM AGAIN!