REPAIR GUIDE - TurboExpress: Sound Fix

[Duo_R]

Yes - I did it last night. It would have only been a 30 minute job but I saw some other caps that looked bad and I can't walk away without replacing. So it was a TE that had no sound and no video....and here it is now:

0913080051fz6.jpg

Video works, the sound is nice and LOUD both using the internal speaker and headphones.

Now I used a different technique than D-Lite, I like making things more similar to how they were when new, so I didn't use any wires to relocate the caps. I can post pictures if you guys want. I tried getting smaller caps (if any of you live near a Fry's this is the way to go) and in some cases got creative and mounted the caps more horizontally if space was an issue. Took lots of pics during the install, and I also have a technique on remove the original caps. I call it the "lift technique" and can describe in more detail if it is helpful. I will probably post this info up on my website (needs something new on it anyway).

Well - TE sweetness. There is a ton of room to work with in some areas on the TE. The first thing I am kicking around is getting a rechargable battery pack and plug so you wouldn't never have to swap batteries out again. If I could get a pack that is smaller than the 6 AAA's, then that would give some room for other projects. Here are a couple of ideas I have for this unit:

* built-in rechargeable pack
* upgrade to a 3-3.5" screen
* built-in memory unit (ala Turbo Booster Plus)
* RGB Out
* Controller port

Of course the purists would yell at me for considering this, but I can't help it. I figure if I bring something back from the dead I have a say on what to do with it (my Frankenstein theory).

So here is where I need some help:

donations of broken controllers, multitaps (so I can get controller ports and cables)
A Turbobooster that is no longer needed or allow me to "borrow" (I need to know what consists of the memory module and see if we can somehow shrink that down to fit)
Suggestion for an RGB screen (does Ben Heck just steal from portable TV's?) - the PS1 is too big
I don't want to do any external modification on the screen, I just want to fit on the inside with a larger screen. 3.5 is more realistic.

Now I haven't played this system in say 15 years, does the LCD sometimes carry ghost images? I remember being blown away by this system (and it is still nice) but of course having a PSP you really can't get better quality LCD these days. I somehow want to bring the screen up to date (and dead pixels aren't as much of an issue anymore).

But would you describe the LCD to be a little grainy, ghosty?

Well I want to make it look as good as it does on my PS1 LCD screen (looks killer).

0901081408apz3.jpg

[Ceti Alpha]

Nicely done. 

[Duo_R]

OK, first this is the technique I  use to remove the caps. Lift technique - you heat up one side of the SM cap, I use a little bit of solder and the iron and heat it up nicely. I then start to lift by either the use of a small jewelers screwdriver, or needlenose pliers. You just keep lifting until you can use the iron to remove all the solder connecting to the board. Be very careful, too much force and you could lift the other leg off the board.

0912082301qf1.jpg

Once you get one side disconnected, I then bend the cap back down to the original position (bending the other leg back). I then use needlenose and then twist back and forth until the other leg breaks.

0912082307yl6.jpg

Then I installed the caps again like so:

0912082339auj8.jpg

Note, I replaced both even though the guide says just one of them. Here is why -when I see a cap that doesn't look like it is in good condition, I replace it. Same theory for a mechanic, if you are already doing work and have parts taken apart, it makes sense to replace parts that might go bad soon since you already have things taken apart (well sense for your car, not for your pocketbook).

The other reason, is by removing both caps, I can install with the horizontal technique. You can see how I have one of the caps bent, this is before I bent the 2nd cap. After I looked at this picture I realized that it looks like one of the caps has the other one bent over....

Here is the final pics of the caps installed before I put the shield back on. Removing the shield isn't necessary, but wanted to peak under the hood.

0912082343rr8.jpg

You can see I also replaced the larger yellow cap - the same thing again about replacing things that look like they are going bad (leaking, etc). It is just easier to replace once for me and put back instead of opening up over and over. I put a little electrical tape since one of the caps is very close to some SMD parts. I didn't want the cap to bend a little when putting back into the housing and short something on the board. A little tape and it is taken care of.

[Dazz]

I would like this done to my Express, please PM me with price in mind.

[agt_dale_cooper]

Did this yesterday to two Express units, both work famously now.  Used Nat's idea for the 47 (as opposed to the 33) as well, and the thing is quite loud.  Disappointed to post, however, that the subminis I used from Parts Express (47uF 10V Sub Mini Radial Capacitor, 020-1604, and 100uF 10V Sub Mini Radial Capacitor, 020-1606) were actually LARGER than the original NEC caps, and I was forced to remote mount down the sides of the PCB.  Ordered/bought subminis in an express attempt to avoid remote mount, but these didn't fit, just a bit too tall.  Commented them as such on their site.  If you're looking for parts grab the physical dimensions of these from their site and see if Digi-Key or Mouser has smaller pieces....

[Duo_R]

Just sharing the latest and greatest, this is how I am replacing these now (the whole audio circuit). You can fit two caps on the top of the audio jack port. And you can see where I am tucking the other two. I use a little hot glue to hold the cap on the left and use a little shrink tubing on it.

img0040sjy.jpg

[Turbo D]

Hello fellow PCEFXers!,

Did you replace all of the capacitors in the audio amp on your TE only to be slapped in the face with a 60-cycle hum coming out of your speaker? Do you need a solution? Then look no further! Pictured below is a capacitor worth replacing if you are experiencing a 60-cycle hum out of your speaker after you have replaced all of the capacitors in the audio amp. The capacitor is 100μF 6v and is located under the shielding.




turbo D's Quick tips!:

Quick tip 1:
60-cycle hum is usually caused by a bad capacitor and/or ground!

Quick tip 2:
When installing a new capacitor, it is okay if the voltage rating is higher than the original capacitor as long as the microfarads (μF or MFD) rating is the same. This is because the voltage rating of the capacitor is a limit not a requirement. However, you cannot replace your capacitor with one having a lower voltage rating. Also, a capacitor with a higher voltage rating will theoretically last longer. Do note that the higher the voltage rating, the larger in size your capacitor will be.

Quick tip 3:
When installing a polarized capacitor, make sure you do not reverse the polarity when installing ( e.g. solder negative to positive and vise versa.) The result will be an explosion of acid! If you are unsure of which lead is positive or negative, remember this: the negative lead of the capacitor will have a strip of arrows above it. If you have a capacitor with leads coming out of both ends, then the negative lead will be the lead that the arrows are pointing to. This is because the electricity flows in to the positive and out through the negative, hence the arrows indicating flow direction. Simple!

[Charlie]

Quickie here:
I see that attachments are limited to 128k, but my bmp files are like 2Meg.  What's the best way to get them posted here?

Thanks
Charlie

[Turbo D]

I upload my pix through http://photobucket.com/. I usually re-size my pix with photoshop before uploading, but it is not required as photobucket will re-size them for you.

[Charlie]

For the technically interested, the TE audio circuit and signal path explained:

Note #1: This text relates to the follow three bitmap files. 

Note #2: The quoted characters in this text represent the identical characters in the schematic, which match the identical characters
shown on the PCB pics.  The uppercase circled points in the schematic represent both the vias as shown on the circuit board pictures,
and the quoted characters given in the text below.  Likewise, the lower case circled points and text represent the
headphone jack pins.  Numeric values represent component pin numbers; an asterisk is Ground.

For speaker :
From Pin 2 of VR100, the volume control to via "K", to headphone connection "g", to headphone connection "f" (switch between "g" and "h" is open without headphones inserted), to one of two amplifier circuits (A+) in IC100 (pin 7), out pin 1 to "B", to CC103, through CC103 to "C", through L100, to "G", on to L103 to headphone connection "e".  A normally closed switch inside the connector routes the audio to "d", which routes to the speaker.

For headphones:
From Pin 2 of VR100, the volume control to via "K", to headphone connection "g", through switch to headphone connection "h" ( switch is closed when headphones are inserted), to via "F", to second of two amplifier circuits (B+) in IC100 (pin 6), out pin 3 to "T", to
CC104, to "L", through L101 and L104 to headphone connector "b" and "c", and out to both headphone speakers, giving pseudo-stereo.
Note that, when the headphones are inserted, connection "g" to "f" is NOT disconnected, thus, the speaker amplifier A+ is still active. 
Therefore, the speaker circuit is still creating an amplified signal for the speaker.  But, when the headphone is inserted, the switch
between "e" and "d" is opened, thus disconnecting the signal from the speaker.

Charlie


ABBREVIATED AUDIO CIRCUIT SCHEMATIC

TE BOARD TOP VIEW

TE BOARD BOTTOM VIEW

[Platinumfungi]

Nice work Charlie  Thanks for sharing the info 

[milkmanv1]

Oh man, thanks soooo much D-Lite, Who woulda thought changing something as simple as ONE cap,  could go from no sound, TO LOUD SOUND! Thanks so much, you saved me a buncha money (and not on my car insurance!!)

[TheClash603]

Yikes, I figured the explanation to fix the problem would be "shake the unit" or something an electronic moron could fix.  Looks like I will have to stick to playing my Express with headphones...  this looks like rocket science.

My broken Twin Famicom is also crying

[override]

Yikes, I figured the explanation to fix the problem would be "shake the unit" or something an electronic moron could fix.  Looks like I will have to stick to playing my Express with headphones...  this looks like rocket science.

My broken Twin Famicom is also crying

I just recently posted very good pics of doing a full cap replacement - HERE, if you would like to refer to them. I can do the repair for you aswell, PM me if your interested. It would run you S/H, Parts and Labor - $35.

[ApolloBoy]

I just fixed my new TurboExpress and I just wanted to say that you can substitute the 100uF caps with smaller ones. I used 68uF caps in mine and the sound is nice and loud.

[christoph]

So the sound and headphones were not working AT ALL on my Turbo Express and I did this mod - the sound now works in both the headphones and speakers - but its the infamous low sound. Low in both speakers and headphones. What do you recommend doing?

[blueraven]

Start looking around the board for capacitors that have broken or corroded legs; check for electrolytic fluid on the board. I'm guessing that you may have another bad capacitor. the 2 big 100's around the sound caps have been bad in the last 4 units I have opened up  ~ but be careful and work very slow ~ The traces love to come up in this area.

[christoph]

100uf 35v caps will work for those right ?

and I replace which ones, green or blue: (I already removed one cap in the green and replaced another with the guide)

/tefix2.jpg
/tefix1.jpg

[blueraven]

The area in green. Start there in your search.

The two tiny caps in the green area are 33uf (microfarad) capacitors - Those are the Sound Caps! Replace them first. You can upgrade them to 45uf to "Hot Rod" it for sightly louder volume.

You're getting close.

[christoph]

Nice. I think I'm gonna upgrade it to 45uf. Thanks mate.

[blueraven]

Correction, 47uf. No problem; Red Ghosts capacitor chart will help too, here's the link:

https://www.pcengine-fx.com/forums/index.php?topic=5303.0

After staring at it for about 15 minutes, everything should start to make sense.

[christoph]

lol

this website is so awesome

[nat]

Actually, all the caps circled in green are in the audio circuit, not just the small ones...

[christoph]

Where is the best place to buy capacitors online? My local radioshack does not have a few of these caps and there is no other local place to shop at.

:/

[kattare]

I got mine in bulk from www.allelectronics.com.  A lot of folks swear by www.digikey.com.  Dunno if that helps or not.

[christoph]

whoa

those sites are awesome

thanks

[Duo_R]

If you replaced all caps in the audio circuit (circled green) your problem should be fixed.

So the sound and headphones were not working AT ALL on my Turbo Express and I did this mod - the sound now works in both the headphones and speakers - but its the infamous low sound. Low in both speakers and headphones. What do you recommend doing?

[christoph]

For anyone who was wondering where to order capacitors from - http://www.digikey.com/ - is fucking awesome.

I ordered 40 various capacitors for $8.40 shipped. It arrived in two days. Great service.

[RoyVegas]

Trying to pick up a few caps locally to fix the sound on my Expresses...  Will a 100 uF 35V work for the sound fix?

[chop5]

thats fine roy,as long as its not under 6v from the original rating. i used a higher voltage on mine i remember cause i couldnt find 6v

[RoyVegas]

I've never done any soldering or repair work before but it seemed easy enough to give it a try.  Worked like a charm!  Thanks to guides and help from cool people on this forum another Express sounds good as new.  Thanks guys!

[Ichibanrei]

Thanks a TON for this guide.  I had scored on a PC Engine GT for 25 bux locally on craigslist of all places.  The sound was out but doing this mod brought it back.  So happy! 

[voidwhichbinds]

thanks a lot for this guide - I've finally gotten around to replace that 100uF capacitor, and it's fixed my TE's very low sound issue..

but for completeness, it should be noted that the highlighted cap in the photo on page 1 is used for the left channel audio - the other 100uF cap is used for the right channel...

[BlueBMW]

I thought the express just had a mono speaker built in?  I guess there's probably a second circuit for the headphones port.

[Charlie]

==>I thought the express just had a mono speaker built in?  I guess there's probably a second circuit for the headphones port.<==

Sort of.  So try:
https://www.pcengine-fx.com/forums/index.php?topic=702.msg116301#msg116301

Charlie

[Duo_R]

Charlie - this isn't exactly sound related, but what kind of part is at L502?

From what I can tell this helps switch power from batteries to external wall plug. I need to replace a bad part on one of my TE units but not sure what to replace it with.

[Charlie]

I'll check.
(Sorry I missed your message)

Charlie

[Charlie]

L501 and L502 are 1uh, .08ohm inductors on the battery input lines.  Looks like they are there for noise reduction purposes, so functionally you should be able to bypass them (short across them).  You don't even have to remove them!  However, they may have an effect on system noise performance. (But you may not care about that).  The easiest way to test that is to simply put a piece of wire in place of them, and see if you notice any negative effects, especially on the video display.

Charlie

[Duo_R]

thanks Charlie, is there a part i can replace those with? Or should i just try to jump?

[Charlie]

Jumping should work fine...functionally.  Just can't tell what may happen performance-wise.

If you want to find a replacement part:
1. Inductance should be ~.8uh to 1.5uh
2. Resistance should be <.12 ohms (lower = better)
3. Footprint must match size on board (DUH!)
4. Current-carrying capacity should be at least equal to that of a AA cell, more = better.
I wouldn't expect to find something that meets all these requirements, but there should be a reasonable compromise out there somewhere.

Charlie

[thesteve]

just a note on capacitor failures in these units.
these capacitors not abused and should not fail.
meaning the failures are from poor part quality and apply to all similar caps used in the unit.
I tested my old caps after removing and found them running @ about half their original value.

another note. my internal speaker didnt work after cap replacement due to tarnish in the headphone jack.
I disassembled the jack, cleaned and reassembled.
works great now

[megamatt]

hello, just wondering if anyone around here would be willing to repair my Turbo Express. i have no soldering experience and i'm afraid i would mess up my Express if i tried to fix the sound issue myself

(i know an offer is in the original post, but that was back in 2005 and i don't know if that offer stills stands. i'm a noob around these parts)

[BlueBMW]

hello, just wondering if anyone around here would be willing to repair my Turbo Express. i have no soldering experience and i'm afraid i would mess up my Express if i tried to fix the sound issue myself

(i know an offer is in the original post, but that was back in 2005 and i don't know if that offer stills stands. i'm a noob around these parts)

I do these repairs.  Shoot me a PM if you're interested.  I can also do a switchless region mod on it if you're interested.

[megamatt]

hello, just wondering if anyone around here would be willing to repair my Turbo Express. i have no soldering experience and i'm afraid i would mess up my Express if i tried to fix the sound issue myself

(i know an offer is in the original post, but that was back in 2005 and i don't know if that offer stills stands. i'm a noob around these parts)

I do these repairs.  Shoot me a PM if you're interested.  I can also do a switchless region mod on it if you're interested.

PM sent, although it's not showing up in my outbox. Let me know if you got it or not

[BlueBMW]

Got it and replied!

[farankoshan]

If the sound is the only problem, should I just have the 100uF & 33uF capacitors (speaker & audio) replaced, or go and do a full cap replacement?

[thesteve]

considering speaker and audio seperately is a misconception.
the speaker connects to the headphone jack directly.
a full cap change will fix things you may not have noticed were degraded yet, while avoiding future failures

[farankoshan]

considering speaker and audio seperately is a misconception.
the speaker connects to the headphone jack directly.
a full cap change will fix things you may not have noticed were degraded yet, while avoiding future failures

I figured as much. Thanks for affirming the right thing to do with these old systems of ours.

[farankoshan]

I swapped all the old caps out (the 470uF 6.3v cap was especially leaky, as were the caps dedicated to audio) for new electrolytic ones, and now my PC-Engine GT is loud, clear, clean and ready for action! Thanks so much to everyone who helps out in their own way on this forum; some little bits of help go a long way for the rest of us.

Lemme know if you guys need me to post pics of how we fit the new caps in.

But for now, excuse me as I make a test run by paying King Fossil a surprise visit...

[coyo5050]

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.

Finally got around to replacing some caps on my TE, did the one for the video and it now works and replaced the 2 100 6v for the sound plus the 100 16v next to those 2. Also replaced 2 other 100 6v that looked suspect. The sound is now very loud but I am getting a hum/buzz. Is this normal? Is this the sound the quoted poster is referring too? I've never had a working TE before so nothing to compare too. Thanks!

Edit:

I notice another post talking about a 60 cycle hum and replacing the 100 6v under the metal shield I am guessing that would be the fix? I tried to get the shield off but was having a hell of a time and gave up.