REPAIR GUIDE - TurboDuo: Sound Fix

[Fakk2]

...replaced every cap that I could (some have strange info on them so I don't know what they are so I could not do all of them)...

This probably isn't what you want to hear, but it might be one of the unidentified caps.  Sorry I can't be on any real assistance. 

If I took pics of the thing can you guys help me then? I mean, I know the PC Engine PAC is rare as hell and nobody has one, but still it is very much like a regular turbo duo just smaller, so there should be ways to repair this unit. I dont care if I must replace every cap on the unit, (theres not many left to replace) I just need to know the values of the caps to buy some new ones. They have weird values on them for example...the ones that read 10  and 16v... were replaced with 10uf caps at 16volts each. The cap that said 47 16s was replaced with a 47uf cap at 16volts..  which should be fine but then I have a TON more with 100  6s on them (Im guessing its 100uf at 6volts?)  and a bunch more with 22  6s  37c on them  which I can only guess would be 22uf at 6 volts?  any ideas?  Anyone here with a LaserActive system that can repair this for me???

[Charlie]

General notes-
C301, 307, 308 are raw power supply filtering. 

For CD audio (sourced at U103 PCM decoder), start at U201 (DAC), come out stereo to U202 filter (caps C205,C206 significant here),through U203 amp/filter, through U504 audio gate, into U505 (caps c617,c618).  Out U505 (through caps c613,c614  -- also, c616 sets frequency response) to U506, out U506 (caps c604,c610) to AV output connector.  Same signal also fed to U507 amp/filter (through caps c670, c671), then output (via c678, c679) to headphone connector.  U507 also uses caps c675 and c676 to set its filter operation. 

For game audio (sourced by U901), come out stereo through caps c878 and c879 into U506, continue as above. 

For ADCPM audio (sourced by U502), come out mono through cap c652 to passive filter (uses c623), to one-half of U503 amp  , out U503 (cap 653) through passive filter (uses c621) to other-half of U503, into U504 audio gate (both channels), continue as above.

C526 is the VCC cap for U515, the 512K ROM.

C323 is regulated power filtering.

Somebody should start tracking this stuff in one of the "sticky" posts, maybe as a table of what cap does what.

Good luck.

Charlie

[Duo_R]

wow Charlie, at 3 posts you sure have a lot of information on the Duo. Did you just trace this yourself?

General notes-
C301, 307, 308 are raw power supply filtering. 

For CD audio (sourced at U103 PCM decoder), start at U201 (DAC), come out stereo to U202 filter (caps C205,C206 significant here),through U203 amp/filter, through U504 audio gate, into U505 (caps c617,c618).  Out U505 (through caps c613,c614  -- also, c616 sets frequency response) to U506, out U506 (caps c604,c610) to AV output connector.  Same signal also fed to U507 amp/filter (through caps c670, c671), then output (via c678, c679) to headphone connector.  U507 also uses caps c675 and c676 to set its filter operation. 

For game audio (sourced by U901), come out stereo through caps c878 and c879 into U506, continue as above. 

For ADCPM audio (sourced by U502), come out mono through cap c652 to passive filter (uses c623), to one-half of U503 amp  , out U503 (cap 653) through passive filter (uses c621) to other-half of U503, into U504 audio gate (both channels), continue as above.

C526 is the VCC cap for U515, the 512K ROM.

C323 is regulated power filtering.

Somebody should start tracking this stuff in one of the "sticky" posts, maybe as a table of what cap does what.

Good luck.

Charlie

[Fakk2]

General notes-
C301, 307, 308 are raw power supply filtering. 

For CD audio (sourced at U103 PCM decoder), start at U201 (DAC), come out stereo to U202 filter (caps C205,C206 significant here),through U203 amp/filter, through U504 audio gate, into U505 (caps c617,c618).  Out U505 (through caps c613,c614  -- also, c616 sets frequency response) to U506, out U506 (caps c604,c610) to AV output connector.  Same signal also fed to U507 amp/filter (through caps c670, c671), then output (via c678, c679) to headphone connector.  U507 also uses caps c675 and c676 to set its filter operation. 

For game audio (sourced by U901), come out stereo through caps c878 and c879 into U506, continue as above. 

For ADCPM audio (sourced by U502), come out mono through cap c652 to passive filter (uses c623), to one-half of U503 amp  , out U503 (cap 653) through passive filter (uses c621) to other-half of U503, into U504 audio gate (both channels), continue as above.

C526 is the VCC cap for U515, the 512K ROM.

C323 is regulated power filtering.

Somebody should start tracking this stuff in one of the "sticky" posts, maybe as a table of what cap does what.

Good luck.

Charlie

So this information is good for Turbo Duo users only or what? I cant find the caps you listed at all in my PC Engine PAC.

[nat]

If you're speaking of the LaserActive PCE pack, then yeah, it's highly unlikely that any information contained herein is going to pertain to anything you find in the LA pack.

[Charlie]

Reference to the Volume Control VR601:

It's connected between C604/C610 and C671/C670 (stereo, of course).  Interestingly enough, instead of the typical connection whereby the audio is the source and the volume control acts as a pot to select some fraction of that audio, in this case the volume control is connected as a "short" across the audio line.  At zero volume, it actually "grounds out" the audio.

Charlie

[Mobius]

I just wanted to say thanks to everyone in this and the various other sound fix/cap replacement threads.  Not because it resolved a sound issue in my Duo, but because it helped me solve something completely unrelated.  Several months ago, I bought a CD32 off of ebay, but the controller was all wonky.  The seller sent me a new one, but the second one started doing the same weird stuff after about an hour of use.

I opened the controllers up to take a look.  I saw a capacitor on the board, and remembering what I had read in these threads about bad capacitors from the early 90s, figured it was worth a shot to replace it.  After all, I had nothing else to go on, and another controller would probably run me something like $40!

Sure enough, it's good as new!  Now I can finally enjoy my CD32 and not have it be a total waste of money.

(And as a side note, the guy at Radio Shack assured me a 47uF/35V cap would be a suitable replacement for a 47uF/10V cap, but that was totally wrong.  Stick with the same ratings!)

[nat]

(And as a side note, the guy at Radio Shack assured me a 47uF/35V cap would be a suitable replacement for a 47uF/10V cap, but that was totally wrong.  Stick with the same ratings!)

Actually, that is totally right. The voltage rating on capacitors is simply an indication of how much voltage the capacitor is rated for. As in, it can withstand up to whatever the voltage rating says. If a 47uF/35V cap didn't work in place of a 47uF/10V cap, it was just a fluke (you probably had a bad cap). You could put a 47uF/999999999999V cap in there (if such a thing existed) and it would behave exactly the same as the 10V because the console is still only supplying the same amount of voltage to it.

[Mobius]

(And as a side note, the guy at Radio Shack assured me a 47uF/35V cap would be a suitable replacement for a 47uF/10V cap, but that was totally wrong.  Stick with the same ratings!)

Actually, that is totally right. The voltage rating on capacitors is simply an indication of how much voltage the capacitor is rated for. As in, it can withstand up to whatever the voltage rating says. If a 47uF/35V cap didn't work in place of a 47uF/10V cap, it was just a fluke (you probably had a bad cap). You could put a 47uF/999999999999V cap in there (if such a thing existed) and it would behave exactly the same as the 10V because the console is still only supplying the same amount of voltage to it.

Huh, weird... Guess it was a fluke, then.  It definitely didn't work.

[agt_dale_cooper]

Interesting....Charlie is my new hero.  [Not to mention already my hero(es) from Military Madness ]
Haven't messed with this PCE Duo that had me resurrecting this thread for a LONG time, I've had other stuff to repair...
Now with a specific plan of attack/testing for the CD audio, I will drag the thing out of the box and trace through those specific points, looking for faults.  I've re-capped the thing twice, but that's not to say that my soldering is invincible...
I also enjoyed the commentary about the headphone jack shorting across the CD audio...fairly certain I tried headphones with the thing and came out with the same really faint audio, so I imagine the headphone jack is NOT at minimum setting....that would be a really stupid solution.
I'm interested to hear if Charlie's commentary prompts other folks with similar audio issues to mine (everything works EXCEPT Redbook from the CD drive, even after replacing laser pickup) to pick up their forgotten-due-to-excessive-irritation no-audio PCEs....

[override]

Interesting....Charlie is my new hero.  [Not to mention already my hero(es) from Military Madness ]
Haven't messed with this PCE Duo that had me resurrecting this thread for a LONG time, I've had other stuff to repair...
Now with a specific plan of attack/testing for the CD audio, I will drag the thing out of the box and trace through those specific points, looking for faults.  I've re-capped the thing twice, but that's not to say that my soldering is invincible...
I also enjoyed the commentary about the headphone jack shorting across the CD audio...fairly certain I tried headphones with the thing and came out with the same really faint audio, so I imagine the headphone jack is NOT at minimum setting....that would be a really stupid solution.
I'm interested to hear if Charlie's commentary prompts other folks with similar audio issues to mine (everything works EXCEPT Redbook from the CD drive, even after replacing laser pickup) to pick up their forgotten-due-to-excessive-irritation no-audio PCEs....

Hello,

Although you seem to know more or less what your doing which is most likely more I just figured I would throw this one out there even though its been posted on this thread before. Have you tried replacing the M51131L chip? or the M5205 18 Pin oki chip?

I had the sound issue and replaced a handfull of suspecting caps (ones that leaked) and it fixed the sound but since it has become faint, and when playing like lords of thunder when you shoot the sound makes a popping noise. I gotta pull it back apart and recheck it all again...Probably another cap leaked...Time to just replace all of em.

[Bludgeon]

Just noticed my Turbo Duo has that problem. When I play the hucard it has all the sound but when I play Ys 1&2 the background music only plays. Kinda strange when I play the disc in my laserdisc player I can hear all the soundtrack but to bad I dont own that laseractive player. One sweet machine and the price is just as sweet to.

[agt_dale_cooper]

FINALLY got around to this.

Assumptions:  If all the ICs are good for the CD audio circuit, then there are a limited number of failure points in terms of caps:  C205, 206 (bottom of board, surface/flat mount) and C617, 618 (top of board, surface/flat mount, to the right of IC505).  [Remaining caps in circuit is all stuff we replaced:  C613, 614, C616, C604 and C610.]

Questions:
1)  What the frell are proper readings for C617 and C618?  I broke out the working-CD audio USA unit, and it's readings (DC V 20m) behaved radically differently than the faint CD audio JAP unit.
2)  Assuming they're frelled, how do we replace?  Too frelling small to get a reading/part number off.
3)  What are C205, 206 supposed to read?  I'm less concerned about them than I am the ones on the top, but I'll ask.

Comments:  Haven't replaced the 5205...I don't see the point before insuring all other circuit components are in working order....
Also pulled the black cover off the lens to insure it wasn't one of the double-style ones where you have to clean the bottom lens too (fixed a recalcitrant SCPH-50001 PS2 by doing this yesterday....spinning the lens height gears (yes, the 50001 has two!) yielded results for DVD5 and CD, but not DVD9.  Took the cap off the lens, cleaned lower lens with my favorite 91%, works like a charm now.)

Thanks for any help, kids.....glad to see this got stickied so it's not me resurrecting the dead again 

[Charlie]

C617,C618 ,C205,C206= .22uf.  Anything 16V or more is ok.

Note that U505 has a CD mute function and a CD fade function on pin 8; check that also.


Charlie

PS: This is probably something else that should go into the "repair data encyclopedia".  (Is anyone actually keeping track of this stuff?  It would make it easier for a user, as compared to having to search all the various posts)

[Platinumfungi]

(Is anyone actually keeping track of this stuff?  It would make it easier for a user, as compared to having to search all the various posts)

I totally agree about recording any useful information. The stickied "REPAIR GUIDES" are actually a very newly implemented feature here and only became so after some requesting was put in the right direction. Anything that's complied into what seems like a nice guide can easily be stickied now 

I'm not sure if it would be the right place, but I'd be happy to update or alter my  "Duo Total Cap Replacement Chart" guide into something a little more like an archive of all the comprehensive repair data, part numbers, proper readings, etc for the Duo. I'd also be perfectly find with someone making some other thread to do so. I don't care who spearheads it, but, just like you, I want to make sure it's actually happening.

I just second the vote to record and archive all pertinent Duo info.

On a side note I made a topic in the hopes of doing the same premise for the often ailing Turbo CD/PCE CD. Hopefully it will one day be of some use to people as well.