Sound problems after recapping my Turbo Duo

Valkyrie · 07/17/2015, 08:26 PM

I got a Turbo Duo with sound issues last week. It sounded fine for about the first 5 minutes, then it started to fade and get crackly. Not unexpected, since it was never re-capped.
I finished re-capping it today, but it's still having sound issues. Now, the right channel has decent volume, but it's still crackly. And I've got nothing at all from the left channel. But if I plug in headphones, it sound just fine through them on both channels.

I did a pretty good job with the caps. No lifted pads or anything. Along the way, I found 3 broken vias, which led underneath IC503. I removed the chip as carefully as I could and repaired the vias, but I can't be sure I didn't damage the chip with too much heat.

Any advice on where to go from here? Does this sound like a problem that IC503 could cause? Or is there something else I should be looking at first?
Thanks!

bozo55 · 07/17/2015, 10:54 PM

Quote from: Valkyrie on 07/17/2015, 08:26 PMI got a Turbo Duo with sound issues last week. It sounded fine for about the first 5 minutes, then it started to fade and get crackly. Not unexpected, since it was never re-capped.
I finished re-capping it today, but it's still having sound issues. Now, the right channel has decent volume, but it's still crackly. And I've got nothing at all from the left channel. But if I plug in headphones, it sound just fine through them on both channels.

I did a pretty good job with the caps. No lifted pads or anything. Along the way, I found 3 broken vias, which led underneath IC503. I removed the chip as carefully as I could and repaired the vias, but I can't be sure I didn't damage the chip with too much heat.

Any advice on where to go from here? Does this sound like a problem that IC503 could cause? Or is there something else I should be looking at first?
Thanks!

I'm having similar problems as you. Your best bet will be to remove the 3 op amps IC506, IC521 and IC5xx (the 8 pin op amp beside 521), and clean the areas around them throughly, jumper any corroded vias, and check for continuity between the op amp and areas close by. I had a bad trace that looked fine.

kyosuke75 · 07/29/2015, 07:58 PM

Quote from: bozo55 on 07/17/2015, 10:54 PM
Quote from: Valkyrie on 07/17/2015, 08:26 PMI got a Turbo Duo with sound issues last week. It sounded fine for about the first 5 minutes, then it started to fade and get crackly. Not unexpected, since it was never re-capped.
I finished re-capping it today, but it's still having sound issues. Now, the right channel has decent volume, but it's still crackly. And I've got nothing at all from the left channel. But if I plug in headphones, it sound just fine through them on both channels.

I did a pretty good job with the caps. No lifted pads or anything. Along the way, I found 3 broken vias, which led underneath IC503. I removed the chip as carefully as I could and repaired the vias, but I can't be sure I didn't damage the chip with too much heat.

Any advice on where to go from here? Does this sound like a problem that IC503 could cause? Or is there something else I should be looking at first?
Thanks!
I'm having similar problems as you. Your best bet will be to remove the 3 op amps IC506, IC521 and IC5xx (the 8 pin op amp beside 521), and clean the areas around them throughly, jumper any corroded vias, and check for continuity between the op amp and areas close by. I had a bad trace that looked fine.

I have the same issue with mine. A friend of mine recapped it. Cd audio doesn't work but you get turbo hucard sound and music. Just no cd audio. He tweaked the laser on it and everything but he isn't sure what the problem is.

bozo55 · 07/29/2015, 08:59 PM

Quote from: kyosuke75 on 07/29/2015, 07:58 PM
Quote from: bozo55 on 07/17/2015, 10:54 PM
Quote from: Valkyrie on 07/17/2015, 08:26 PMI got a Turbo Duo with sound issues last week. It sounded fine for about the first 5 minutes, then it started to fade and get crackly. Not unexpected, since it was never re-capped.
I finished re-capping it today, but it's still having sound issues. Now, the right channel has decent volume, but it's still crackly. And I've got nothing at all from the left channel. But if I plug in headphones, it sound just fine through them on both channels.

I did a pretty good job with the caps. No lifted pads or anything. Along the way, I found 3 broken vias, which led underneath IC503. I removed the chip as carefully as I could and repaired the vias, but I can't be sure I didn't damage the chip with too much heat.

Any advice on where to go from here? Does this sound like a problem that IC503 could cause? Or is there something else I should be looking at first?
Thanks!
I'm having similar problems as you. Your best bet will be to remove the 3 op amps IC506, IC521 and IC5xx (the 8 pin op amp beside 521), and clean the areas around them throughly, jumper any corroded vias, and check for continuity between the op amp and areas close by. I had a bad trace that looked fine.
I have the same issue with mine. A friend of mine recapped it. Cd audio doesn't work but you get turbo hucard sound and music. Just no cd audio. He tweaked the laser on it and everything but he isn't sure what the problem is.

The only thing I can suggest is to thoroughly check for continuity in any of the areas where the caps leaked.

kyosuke75 · 07/29/2015, 09:01 PM

Quote from: bozo55 on 07/29/2015, 08:59 PM
Quote from: kyosuke75 on 07/29/2015, 07:58 PM
Quote from: bozo55 on 07/17/2015, 10:54 PM
Quote from: Valkyrie on 07/17/2015, 08:26 PMI got a Turbo Duo with sound issues last week. It sounded fine for about the first 5 minutes, then it started to fade and get crackly. Not unexpected, since it was never re-capped.
I finished re-capping it today, but it's still having sound issues. Now, the right channel has decent volume, but it's still crackly. And I've got nothing at all from the left channel. But if I plug in headphones, it sound just fine through them on both channels.

I did a pretty good job with the caps. No lifted pads or anything. Along the way, I found 3 broken vias, which led underneath IC503. I removed the chip as carefully as I could and repaired the vias, but I can't be sure I didn't damage the chip with too much heat.

Any advice on where to go from here? Does this sound like a problem that IC503 could cause? Or is there something else I should be looking at first?
Thanks!
I'm having similar problems as you. Your best bet will be to remove the 3 op amps IC506, IC521 and IC5xx (the 8 pin op amp beside 521), and clean the areas around them throughly, jumper any corroded vias, and check for continuity between the op amp and areas close by. I had a bad trace that looked fine.
I have the same issue with mine. A friend of mine recapped it. Cd audio doesn't work but you get turbo hucard sound and music. Just no cd audio. He tweaked the laser on it and everything but he isn't sure what the problem is.
The only thing I can suggest is to thoroughly check for continuity in any of the areas where the caps leaked.

Cool thanks. My friend is looking tonight for any bad traces, etc

Brraap · 07/30/2015, 10:37 PM

Remove all caps + the super cap and wash the entire board. old cap juice under the opt amps can cause this

thesteve · 07/30/2015, 11:39 PM

no need to remove the caps first

wilykat · 07/31/2015, 12:19 AM

^^ this. New non-fake caps are properly sealed and shouldn't suffer from water damage.

wilykat · 07/31/2015, 12:21 AM

double post

mario_pic · 10/01/2015, 12:24 AM

Sorry about hijacking the thread I got same problem with my duo as well swapped out every cap I get crackling in sound I cleaned under ic506 should I lift and clean ic507 ic521 and ic503 I also get same sound crackling from the headphone jack is there a diagram of the audio circuit

bozo55 · 10/01/2015, 12:43 AM

Quote from: mario_pic on 10/01/2015, 12:24 AMSorry about hijacking the thread I got same problem with my duo as well swapped out every cap I get crackling in sound I cleaned under ic506 should I lift and clean ic507 ic521 and ic503 I also get same sound crackling from the headphone jack is there a diagram of the audio circuit

If you solve this problem let me know what you did to fix it. I'm getting the static out of the right channel only and haven't made the time to clean under every op amp yet.

BlueBMW · 10/01/2015, 03:10 AM

Check out this thread here...

https://www.pcengine-fx.com/forums/index.php?topic=17498.msg365761#msg365761

At some point you'll have to just go through the sound circuit piece by piece until you find the spot where something isn't working. I know I've had grounds go bad due to corroded vias and as a result the op amp or whatever that used the ground wouldn't function and sound would go in but not come out of the chip. Build a little probe like described there and starting working your way through the sound circuit.

Keith Courage · 10/01/2015, 05:34 AM

Sometimes if you hear crackling you can get lucky by just leaving the system turned on for a long time. Meaning, maybe after 12 hours or so the short will sometimes go bad all the way making it much more easy to find the shorted out/bad part in the circuit. Every system that I recap I leave turned on over night to make sure no bad traces/shorted sections show up. That old cap goop can really get into things sometimes.

mario_pic · 10/09/2015, 11:02 PM

Quote from: Keith Courage on 10/01/2015, 05:34 AMSometimes if you hear crackling you can get lucky by just leaving the system turned on for a long time. Meaning, maybe after 12 hours or so the short will sometimes go bad all the way making it much more easy to find the shorted out/bad part in the circuit. Every system that I recap I leave turned on over night to make sure no bad traces/shorted sections show up. That old cap goop can really get into things sometimes.

let my unit run for 12 hr playing audio loop still the same nothing changed any info on what points on the ic I could tap for sound

thesteve · 10/10/2015, 02:30 AM

its likely an open via by the heatsinks and the 10UF caps

mario_pic · 10/25/2015, 09:13 PM

Quote from: thesteve on 10/10/2015, 02:30 AMits likely an open via by the heatsinks and the 10UF caps

I made a headphone probe unit to test the sound so far I got clean good sound from the c6280 chip on both left and right audio out points wondering if anyone knows where the first vias for sound feed what amp ic on what leg so far pin 18 and 19 are left and right audio on the c6280 ic

thesteve · 10/25/2015, 10:41 PM

if its chip sound the first stop is the last stop
amp chip between the heatsinks and AV port

Valkyrie · 06/12/2016, 01:22 PM

I just recently finally started digging into this thing again. I removed all of the amp caps and started testing a bunch of traces and vias, but I didn't find anything else obviously bad. I put it back together and was going to try BlueBMW's suggestion of following the schematic and probing for audio. But after plugging it up with a new AV cable, I actually found that it worked pretty well! Turned out, the left audio channel on my other cable is flakey. So that was part of my problem.

In testing it for a while, it seemed good until I realized that the sounds from the ADPCM channel were very quiet. Looking at the multiplexer schematic, I saw it was handled by IC503. That's the one I removed to repair a couple vias when I did the cap job.

I took some voltage readings, and confirmed that it had ground on 8v on pin 8. But where the schematic says it should have 2.5v on pins 3 and 5, I'm getting about 3.8v. And in checking the other pins, they're all reading 3.8v also.

So I'm not really sure where to go from here. Does this sound like a bad opamp at IC305? And is the high voltage on pins 3 and 5 a problem?

MNKyDeth · 06/12/2016, 01:45 PM

Diagnosing the sound issues on the TurboDuo/PCE Duo has been the hardest for me. After a lot, of console repairs I have found that you need to measure the voltage on the top and bottom of the board around the op-amps.

Specifically, IC506, IC503 and IC521. The areas where the traces go through the PCB to the other side of the board I find get plugged up with gunk. Sometimes they are just bad and you need to run a wire from one side of the board to the other. Follow each ground trace to ensure each ground is really ground and not getting voltage somewhere because of corrosion and electrolytic fluid issues.

IC502 is almost always good although I have run into bad IC505's because of so much corrosion on the legs, they just had to be replaced cause the legs on those chips were literally trashed.

If voltages are not within range on the op-amps there is either a short or bad trace and this I typically find by starting with following ground on pin 4 of the op-amps.