REPAIR GUIDE - TurboExpress: Sound Fix

D-Lite · 05/29/2005, 10:50 PM

Haha, not the biggest news in my world, which would be the Turbo Duo sound fix, but this is the other scourge of the Turbo World!

I was discussing the problems with Duo units with TZD's Steve and he mentioned that by far and away the biggest problem for them has been weak/no sound from Turbo Express units, even brand new ones! So I asked if he could send a unit of two and I'd look into it. Tried contacting RetroGames Bob Frasure, but no luck (still, if anyone has a way to contact him please let me know!). So off I went with the multimeter.

So I sat with a TE with a weak speaker and started tracing the circuit back, looking for the culprit which I figured had to be a dead/dry capacitor or dead op amp IC. Since there is a dense mask on the system, I had to do a lot of scraping and shining of light through the PCB to find the contacts. Here's what that looked like:

Notice the Op Amp for the sound highlighted and two little holes through the PCB. These holes are the + and - of a capacitor that leads to the input into the op amp for the audio are also tied to the speaker line which is just above the "03" in L103 on the PCB. Those holes are connected to this capacitor:

So, I figured, likely culprit. I tapped a new 100 uF, 25 Volt capacitor to the proper holes and SUCCESS@!!@!! The sound amplified to a normal level!!!!!! What I've noticed is that there are varying degrees of the sound issue from weak sound to no sound. This mod works with both and even in the worse case it is amped to a satisfactory level. Meaning there is likely another cap somewhere that needs looking at, but this fix will definitely work.

Here's step-by-step instructions on how to do this. I can't make linking pics here to the bigger versions of these, but if you copy the location of the image I have and simply remove the "a" that's after the number, before the ".jpg", then you will get the 800 x 600 version.
All these are in this folder on my site:
https://www.multimods.com/TEsound/

OK, on the back of your TE, remove the 4 screws on the outside and the two inside the battery compartment:

CAREFULLY separate the front and back of the unit enough that you can disconnection these connections. The flat cables should be wiggled gently back and forth to make them loose.

On the rear part of the unit, remove the screw indicated in the pic. Note that the two holes we're soldering too are located where the arrow is pointing:

Closeup of the holes with + and - indicated.

Here's the culprit. You can twist the cap off with a pair of pliers but leaving it in is no problem.

Now take an electrolytic 100uF cap (25 V is what I used, but you can use 10V, 15V, etc) and connect two wires to it, preferably close to the cap body as shown so most of the wire and terminals are coved by insulation. I used wrapping wire (30 gauge), but you can use 22 gauge, which is pushing it on how small the spots you're soldering too are. Wires should be about 1.5-2" long.

And now connected:

Here I've tucked the cap under the PCB where there is ample space to hold it. Note in the picture I have also added a short wire between two places on the PCB. This is connecting the right and left channels on this unit since the right channel was dead. I'm sure the issue with it can be solved, but this works great for addressing the problem at hand.

Now with the PCB reset to it's place, note the location of the wires. All you have to do now is screw in the proper screws and reconnect the cables (carefully! I use needlenose pliers for the flat cables so I don't bend them) and you're done!!!

So, there it is. You can buy the capacitor dirt cheap in packs of 10-100 from DigiKey or Jameco and even Radio Shack has the capacitor. All you need after that is 3" of wire and soldering equipment. Oh, and a small Phillips head screwdriver.

If you need yours fixed, I will probably start offering to fix them for people shortly. Shipping plus maybe $10 for the fix. So about $20 shipped back to you (you pay shipping out, and then it's about $10 back to you). I figure there are a lot of people that are nervous about soldering such small connections and opening anything electronic like this, so I'll probably offer to do this. We shall see on this, but most importantly I wanted to make this available for everyone!

Next biggy, and the one I'm most passionate about, the Duo sound issue!!!

OldRover · 05/29/2005, 11:08 PM

Excellent man. Very excellent.

DragonmasterDan · 05/29/2005, 11:15 PM

That's cool, the only problem I've had with my TE is that the turbo switch will actually disable my I button when its stuck in between normal and the low level turbo. I've heard quite a bit about the sound issues though, at one point I thought I had that problem. It turned out I needed new batteries :-D

esteban · 05/29/2005, 11:29 PM

Simply superb.

TurboHuC6280 · 05/30/2005, 01:00 AM

Nice find. This is as I've expected for some time (as it's the most logical failure point), but I've not had a broken one one to test this theory. I suspect something similar going on in the Duo systems, but it's undoubtably a much bigger task since there are two seperate audio circuits (one for typical FM synthesis and the other for CD audio). CD audio isn't particularly complicated though. It normally consists of (after the drive) only a DAC and an opamp, and a few other little things like caps, so it really should be pretty simple.

I know that you marked the polarity, but it is important to stress to everyone that these caps are *polarized* and you can blow the electrolytic caps if you have it soldered in backwards. Also, pulling apart a Turbo Express can be pretty complicated for novices. It takes a bit of care to get everything back in there just right.

Nice work.

Keranu · 05/30/2005, 01:29 AM

Awesome information. I'll look to you if I ever get an Express (which I surely will some day) and need help with that problem.

D-Lite · 05/30/2005, 02:56 AM

Quote from: zborgerdNice find. This is as I've expected for some time (as it's the most logical failure point), but I've not had a broken one one to test this theory. I suspect something similar going on in the Duo systems, but it's undoubtably a much bigger task since there are two seperate audio circuits (one for typical FM synthesis and the other for CD audio). CD audio isn't particularly complicated though. It normally consists of (after the drive) only a DAC and an opamp, and a few other little things like caps, so it really should be pretty simple.

I know that you marked the polarity, but it is important to stress to everyone that these caps are *polarized* and you can blow the electrolytic caps if you have it soldered in backwards. Also, pulling apart a Turbo Express can be pretty complicated for novices. It takes a bit of care to get everything back in there just right.

Nice work.

Thanks. I really enjoy this stuff so figuring out solutions like this keeps me going.

With regards to the Duo, I've traced the circuits and I know where all the op amps are and I can figure out the caps. BUT, and this is a big BUT, like JLo big, I can't easy test which it is because I need to physically access the caps while the lid is on since I need the CD cover in place to hold the disc. I think I have the solution to that though. Hoepfully I'll have the *cure* posted for that soon too

twor2005 · 05/30/2005, 02:31 PM

Good work. In fact this deserves better than a post on a forum. Maybe Aaron will put this on the site!

Liquid Snake · 06/01/2005, 08:05 PM

D-Lite is the man!!!!!!!!!!!!!!!!!!

You wanna to show us your TG/PCE game/console collections?

PCEngineFX · 06/04/2005, 01:20 AM

Great work D-Lite! I read over your instructions and seems pretty straight forward to follow. Speaking of TE's, I have a TE that is in need of the sound fix and I'd rather have you do this than me....when you taking orders?

shadowlife25 · 03/20/2006, 05:10 AM

Hey D-Lite, I just wanted to say thank you for posting such an informative (and picture filled

) rewiew and also i wanted to say that the sound fix works wonderfully. now if I could just figure out how to do the screen fix...
Anyhow, many thanks!
M.

ctoomey · 02/16/2007, 04:46 PM

I did this fix today and it works like a charm. Thanks so much for the post!

I would be willing to fix peoples units if there is a need out there.

If you would like to discuss please let me know via email: ctoomey75@hotmail.com

Thanks again D-Lite

Keranu · 02/16/2007, 07:28 PM

I still need this done for my Express, but still not sure if I should do it myself or not.

ctoomey · 02/16/2007, 07:34 PM

I have decided to do this for a limited number of folks that need it. Check out the forum topic TURBO EXPRESS SOUND REPAIR for details. Thanks!

GUTS · 02/17/2007, 01:49 AM

Haha I did this fix on a friend's express with a part from a dead Xbox motherboard. Awesome.

grahf · 02/17/2007, 04:00 PM

For anyone with the means to solder smaller stuff, you can get the SMD caps identicle to the bad ones at mouser.com. Im pretty sure thats where i got mine. Im going to replace ALL the caps in my nicest unit.

grahf · 02/18/2007, 08:35 PM

Well, I replaced all four caps in the audio amp circuit. The result is perfect sound. This thing is LOUD, way louder than my DS or GBA. I cant believe this is how its supposed to sound, after listing to it in wisper-mode all this time

I was mistaken, I got the caps from Jameco. I can provide part numbers if anyone is interested. The hardest part of this job is removing the shields. A bit of desoldering braid is needed, and a fine tip soldering iron is a MUST. The picture below is of my parts/project GT, and has the handsfree jack removed as well. You dont need to remove it (I didnt on the one I did today), but it would give you more room. I'm going to go back in later and replace the rest of the caps for good measure.

Seldane · 02/19/2007, 10:59 AM

What the hell happened there in the corner?

grahf · 02/19/2007, 12:02 PM

Some parts of the PCE GTs come coated with this rubbery/glue junk. I just scraped it away a bit to see underneith on this board.

esteban · 02/19/2007, 12:03 PM

Quote from: Seldane on 02/19/2007, 10:59 AMWhat the hell happened there in the corner?

Obviously, the marshmallow he was eating fell from his mouth and melted on the board.

grahf · 02/24/2007, 04:13 PM

you know, for the most part the Express/GT is very well constructed (just like the PCE). But i cant for the life of me figure out why they felt the need to cover certain things will goop. Its common practice to coat some things, but not just randomly glob it on there.

PCEngineHell · 02/27/2007, 05:12 PM

They did it to insulate that area I guess,assuming it is a more high risk area of the pcb component wise.

grahf · 02/27/2007, 06:19 PM

Yeah, but one must wonder why they didnt just use the common shellac style coating. Maybe they thought the glue would help the heavier components from jolting loose from a drop.

Or, maybe someone brought their kids into work with their elmers glue bottles

Tatsujin · 02/27/2007, 07:38 PM

question: isn't it just that easy to replace only this 100uF/6V capacitor?

:edt: grahf already mentioned about that. fine

btw: did someone try to use doublelayer/tantalum capacitors instead of electrolytic, since they can't dry out, which causes the problem of losing the sound. of course i'm aware, that for audio applications there isn't something better than the good ol' electrolytic caps. but we're not talking about HIFI here ;)

Tatsujin · 02/27/2007, 11:02 PM

Quote from: grahf on 02/27/2007, 06:19 PMYeah, but one must wonder why they didnt just use the common shellac style coating. Maybe they thought the glue would help the heavier components from jolting loose from a drop.

Or, maybe someone brought their kids into work with their elmers glue bottles

seems like it's the part for stepping up the voltage which is needed for the neon-lamp for the backlight (about 100VAC). sometime parts, especially coils have to be fixed/reinforced with some glue to the PCB, since they shaking slightly in a high frequency, which could cause a broken soldering over the time of use.

ctoomey · 03/02/2007, 03:43 PM

I've done this on a few units with success but experience a bit of 'hum' in both the speaker and when listening through headphones...I have not pulled the dry/old capacitors since it doesnt seem necessary and I am using 100uf 50V capcitors...

Thoughts on how to limit the hum?

Thanks!!!

grahf · 03/02/2007, 05:18 PM

I get the same hum, and im pretty sure its normal. I dont know how it is on yours, but on mine it only occurs when the volume level is pretty high. My portable dvd player does the same thing (as do a lot of electronics).
It is also possible that one of the other dry caps on the board is allowing interference to bleed into the audio. When I have time I may replace all the other caps on the board, but its no rush because it sounds normal to my ears.

Tighe · 03/10/2007, 11:15 PM

Quote from: shadowlife25 on 03/20/2006, 05:10 AMHey D-Lite, I just wanted to say thank you for posting such an informative (and picture filled ) rewiew and also i wanted to say that the sound fix works wonderfully. now if I could just figure out how to do the screen fix...
Anyhow, many thanks!
M.

About a year ago my beloved TE's sounds kept getting quiter and quiter, until one day the video stopped being displayed too! I was so sad and knew if I spent a lot of time I could figure out the faulty circuit, but I just didn't have that time. After reading this post, I was so excited I ran to the basement and replaced the capasitor as suggeted, and WOW the sound was back!!! Now the real question is will replacing all the capisitors return the video? The backlight still works, I can ouly assume that the problem is with the main board not the video driver. I will be ordering exact replacements as they will be much easier to install. I will post here with the results. Thanks D-Lite!

http://nestable.classicgaming.gamespy.com

ctoomey · 03/10/2007, 11:49 PM

Cool! Where are you ordering the replacement vid caps from?

ctoomey · 03/12/2007, 07:20 PM

Grahf, I was curious why you replaced all 4 of the caps...It seems that just following D-lite's sound fix works well, even if you leave the old ones in place?

grahf · 03/12/2007, 10:18 PM

Just replacing the single cap did not work for me. In fact, it made the sound stop working alltogether. The audio opamp NEEDS all four of those caps by design, but it just so happens that the one D-lite pointed out is most crucial for operation and will fix most peoples problems (but probably not 100%).

I dont think the screen can be replaced by replacing caps. The screen takes RGB input, and from my tests the signal comes almost directly off of the hu6260. Sounds like your screen itself is bad, and unfortunatly it probably cant be fixed. Old lcds like these are just really flakey.
When I have time, I have a modern LCD from a pocket tv that I plan on hacking to take RGB, and putting that in one of my Expresses. It will be nice to have a system with modern LCD.

Tighe · 03/14/2007, 07:02 PM

Quote from: grahf on 03/12/2007, 10:18 PMJust replacing the single cap did not work for me. In fact, it made the sound stop working alltogether. The audio opamp NEEDS all four of those caps by design, but it just so happens that the one D-lite pointed out is most crucial for operation and will fix most peoples problems (but probably not 100%).

I dont think the screen can be replaced by replacing caps. The screen takes RGB input, and from my tests the signal comes almost directly off of the hu6260. Sounds like your screen itself is bad, and unfortunatly it probably cant be fixed. Old lcds like these are just really flakey.
When I have time, I have a modern LCD from a pocket tv that I plan on hacking to take RGB, and putting that in one of my Expresses. It will be nice to have a system with modern LCD.

Actually in my case I tested the screen and it is functional, the problem is with the system board.

nat · 03/21/2007, 11:33 PM

Quote from: grahf on 03/12/2007, 10:18 PMJust replacing the single cap did not work for me. In fact, it made the sound stop working alltogether. The audio opamp NEEDS all four of those caps by design, but it just so happens that the one D-lite pointed out is most crucial for operation and will fix most peoples problems (but probably not 100%).

I dont think the screen can be replaced by replacing caps. The screen takes RGB input, and from my tests the signal comes almost directly off of the hu6260. Sounds like your screen itself is bad, and unfortunatly it probably cant be fixed. Old lcds like these are just really flakey.
When I have time, I have a modern LCD from a pocket tv that I plan on hacking to take RGB, and putting that in one of my Expresses. It will be nice to have a system with modern LCD.

Thanks to your post in another forum, I found out my GT isn't dead after all. The fuse was just blown. I bypassed the fuse and all is well.

However, I uncovered a different problem. I replaced the one cap D-Lite mentioned but my aduio is still not working. In fact, it didn't help anything at all. Looks like I need to replace the other 3 as well. Will you post those part numbers?

grahf · 03/22/2007, 12:08 AM

Yes, no problem. I ordered the replacement caps from www.jameco.com You have to search by "catalog #".

You need two "193017". The originals are 33uf 6v, the jameco replacements are 33uf 16v.
You need two "192903". The originals are 100uf 6v, the jameco replacements are 100uf 6.3v.

Just a few pointers: you WILL need to pick up some desoldering braid for this job (radioshack). You have to remove the shields, and some of the posts are impossible to get to with a desoldering tool. A well placed piece of braid and fine tip soldering iron will make things easy. Also, it can be hard to get to the 100uf caps if your soldering iron isnt small enough. You can desolder the headphone jack for easier access. Its a lot more work, but it depends on what your working with. Good luck!
-Ben

Torx · 06/10/2007, 02:57 AM

WOOTTT!!!! i just repaired mine!
man i got scared as heck, i accidentally got molten solder on the tiny little transistor rectangle thing and accidentally pulled it up a little.. i almost fainted..
then i heated it up and push it down.. put it back together with fingers crossed and it works great!!

thank you d-lite and others, when i got time and money i'll be replacing all of them.. but as of now.. the sound is great and loud!
i left the cap in just in case others are wondering..

i just hope this modfix wont have any ill effects in the future...

nat · 06/10/2007, 02:08 PM

My GT had audio that didn't work at all, not even with headphones. I ended up just replacing the one cap, which turned out to be a huge chore in itself. My hands are too large and unsteady to be working on a PCB that is so cramped and small. I blew the fuse in the process, which I luckily bypassed with no ill effects.

Anyway, after replacing the one cap, I now have loud sound over the headphones but the speaker is still dead. I'm going to leave it at that and call it good-- after reading what grahf suggests for replacing the other caps, I'm calculate an 85% chance of destroying my GT if I were to attempt it. Especially after the trouble I had with the "easy" one.

It's OK, because I would normally use headphones most of the time I played anyway.

jimid2 · 06/13/2007, 09:40 AM

Well, I (well, a more technically adept friend of mine, actually) managed to get two of the caps replaced in my "headphones only" TE before giving up in nervous exhaustion - but it was enough! I've got sound!! Not loud enough to be heard on a bus, but plenty loud for playing on the couch in my home, even with the stereo on in the background.

It's thanks to this post that I've got this far, and I wanted to say so! Mucho graçias!

rastoma · 09/27/2007, 04:06 PM

Quote from: grahf on 03/22/2007, 12:08 AMYes, no problem. I ordered the replacement caps from www.jameco.com You have to search by "catalog #".

You need two "193017". The originals are 33uf 6v, the jameco replacements are 33uf 16v.
You need two "192903". The originals are 100uf 6v, the jameco replacements are 100uf 6.3v.

Just a few pointers: you WILL need to pick up some desoldering braid for this job (radioshack). You have to remove the shields, and some of the posts are impossible to get to with a desoldering tool. A well placed piece of braid and fine tip soldering iron will make things easy. Also, it can be hard to get to the 100uf caps if your soldering iron isnt small enough. You can desolder the headphone jack for easier access. Its a lot more work, but it depends on what your working with. Good luck!
-Ben

Hi Ben,

Thanks for the info. Do you have extras of these? Or does anyone here want to go in and buy them and split them?

I know the cost is very cheap, it's not a matter of cost, I just hate wasting things or throwing something a way that's good. I know I'll never use 10 each of these and only need 2 each as stated.

Ceti Alpha · 09/27/2007, 04:16 PM

Wow! I don't have a TE, but all the effort you put forth in this area is amazing!

And your step-by-step guides are awesome.

Wolfeman · 10/09/2007, 12:53 PM

Quote from: nat on 03/21/2007, 11:33 PM
Quote from: grahf on 03/12/2007, 10:18 PMJust replacing the single cap did not work for me. In fact, it made the sound stop working alltogether. The audio opamp NEEDS all four of those caps by design, but it just so happens that the one D-lite pointed out is most crucial for operation and will fix most peoples problems (but probably not 100%).

I dont think the screen can be replaced by replacing caps. The screen takes RGB input, and from my tests the signal comes almost directly off of the hu6260. Sounds like your screen itself is bad, and unfortunatly it probably cant be fixed. Old lcds like these are just really flakey.
When I have time, I have a modern LCD from a pocket tv that I plan on hacking to take RGB, and putting that in one of my Expresses. It will be nice to have a system with modern LCD.
Thanks to your post in another forum, I found out my GT isn't dead after all. The fuse was just blown. I bypassed the fuse and all is well.

However, I uncovered a different problem. I replaced the one cap D-Lite mentioned but my aduio is still not working. In fact, it didn't help anything at all. Looks like I need to replace the other 3 as well. Will you post those part numbers?

I have the same problem with my screen, can you post a photo of where the fuse is you're talking about?

WoodyXP · 04/11/2008, 03:01 AM

Thank you very much for posting this fix, Mr. D. I was able to fix mine and it is LOUD!!
My quality of life has increased immensely.

And sorry for bumping this old assed thread.

nat · 04/11/2008, 10:51 AM

I may have some information soon to add to this thread regarding the sound circuit. Stay tuned (pun intended).

chop5 · 04/23/2008, 12:57 AM

thanks dean did the 1 cap soldered to the two VIA's,works perfect

Ceti Alpha · 04/23/2008, 08:41 AM

Quote from: nat on 04/11/2008, 10:51 AMI may have some information soon to add to this thread regarding the sound circuit. Stay tuned (pun intended).

groooooaaaaannnnn!!!

Who am I kidding? I love cheesy puns.

VestCunt · 04/25/2008, 12:22 AM

Is anyone having problems with one of the stereo channels not working in the headphone jack? Two of my 3 TEs have been fixed using D-Lites instructions but only output the left channel if I use headphones. The third, with the common sound problem making the speaker so quiet it's almost inaudible, plays fine through BOTH headphone channels.

nat · 04/25/2008, 12:23 AM

Replace both the 100uf capacitors in that cluster to equalize the volume for both channels.

nat · 07/02/2008, 01:55 PM

I want to add something here.

Sometimes replacing the two 100uf caps doesn't completely fix the audio in these units. You also need to replace the two 33uf caps in sequence with them.

The one problem here is that 33uf caps are kind of hard to find, save for special ordering them online.

I did some testing and 47uf caps work 100% as a suitable replacement (and are much more common), and actually result in a louder sound volume than using 33's.

By replacing the 4 caps (2 100's, 2 33/47's) in the sound circuit, you will restore audio functionality to 100% unless you have a bad speaker. Also, both sound channels will be equalized over the headphones so D-Lite's shunt pictured on page 1 isn't necessary.

Vanquish · 08/06/2008, 08:53 AM

Hey! This is great. Just wanted to say thanks and CONGRATULATIONS!!!

Duo_R · 09/13/2008, 04:24 AM

Well - I performed the Audio and Video cap mod today....and I brought a Turbo Express back to life (both were bad).....am I hero? No. Did I save a life? Yes a Turbo Express! You know who is a real hero? Hiro from Heroes.

Ratix · 09/13/2008, 02:18 PM

so this is what you did last night >.> i sold both my TE's a very long time ago because of that sound issue i feel like a fool for soing it to because i got ripped off when i sold them.