Coregrafx Sound Issue

[wolfman]

Had to switch from my LT to my region-modded Corgrafx due to power problems 

From my Coregrafx I don´t get any sound...when I turn up my stereo all the way I can faintly hear game sounds...so at least something is coming trough.

Where would I have to look out for on the board? I can´t seem to find a chart or a hint on sound repairs for this model...

This is my current setup:

-Coregrafx with original AV-Cable ---> Cinch Adapter ---> Stereo Amplifier

Any hints/tips?

[thesteve]

For starters on the CG sound issues are not common
Further is the sound missing from cards or CD games?
Does the sound work without the CD hardware (IFU/SCDR2)?

[wolfman]

For starters on the CG sound issues are not common
Further is the sound missing from cards or CD games?
Does the sound work without the CD hardware (IFU/SCDR2)?

This is what I tested yesterday:

-Coregrafx is in my WORKING IFU, CDROM2 is also working correctly, so I can sort that out. Since I modded my IFU in a way that sound has to come through the output of the Coregrafx/PCE/LT, I can assure that its not briefcase-related.
-Sound issue came up with a Card game. I didn´t test a CD game yet on the Coregrafx (but it works fine with LT on the same setup).

Do you think its the DIN jack or cable? I get picture through the AV cable, and very very very faint sound when I turn up my stereo all the way. Will test another input today on my stereo...but since sound doesn´t come as well on my TV when I plug it in directly, I am somewhat puzzled as to what it could be......

Will test the missing setups from your last post today and let you know.

Any further hint perhaps that I could look for too? Is there a chance that there´s trouble with the region mod (although it works with US/JP when I flip the switch)?

[pulstar]

It's not common on a Coregrafx system, but it could be the electrolytics in the audio section (or the amp). I'd check the AV cable first though.

[wolfman]

It's not common on a Coregrafx system, but it could be the electrolytics in the audio section (or the amp). I'd check the AV cable first though.

Where´s the audio section on the board located?

[wolfman]

For starters on the CG sound issues are not common
Further is the sound missing from cards or CD games?
Does the sound work without the CD hardware (IFU/SCDR2)?

So, I checked everything and found the following:

-ONLY IFU puts out CD sound thru its connectors, it doesn´t pass Sound thru Coregrafx/AV out
-L/R audio doesn´t seem to get to DIN connector on Coregrafx (no chiptune).
-I only get sound from Coregrafx directly when I connect L/R audio from expansion port to DIN connector (only chiptune, NO CD sound however).

So what could be the reason? The DIN connector seems fine, all contacts seem fine (otherwise there would be no output at all...)...

Caps? A defunct chip or controller? Bad traces? Where should I look for?

[thesteve]

ok no need to test other setups (was just covering my bases)
the CG DIN will never pass CDA
DIN and EX Bus output the same sound (chip tunes only)
full sound must come from the IFU directly, as it mixes the chiptunes into its sound circuits

[wolfman]

ok no need to test other setups (was just covering my bases)
the CG DIN will never pass CDA
DIN and EX Bus output the same sound (chip tunes only)
full sound must come from the IFU directly, as it mixes the chiptunes into its sound circuits

Thanks for the hint on the IFU,  this is new to me. However my LT mixes Chiptunes AND CD sound, putting it all out thru headphone jack! This way I got all sound on my stereo...so this is impossible with Coregrafx???

The strange thing is - without a direct bridge from the expansion bus to DIN I wouldn´t even get chiptunes! Where should I look for damages on the board? Or what could it be?

[thesteve]

are you saying your not getting chip tunes to the ex bus or the din?

[wolfman]

are you saying your not getting chip tunes to the ex bus or the din?

WITHOUT modification I DON´T get chiptunes from DIN on Coregrafx, BUT on IFU thru EX. Thats what puzzles me...

[thesteve]

if its there at the IFU then its usable by using IFU outputs
not sure if they have anything between the DIN and BUS on the CG

[wolfman]

if its there at the IFU then its usable by using IFU outputs
not sure if they have anything between the DIN and BUS on the CG

Do you know if there is any board layout on the interweb? Tried searching but couldn´t find anything...don´t want to remove the whole shield from the pcb underside just to look where traces go...

[thesteve]

I don't know of any layout info out there
I'd have to remove the shield and trace it

[Fidde_se]

And even if there would be and decent signal at the CGs DIN
its still only mono for ADPCM and CDA as only pin B1 is sending that
those signals back from the IFU.

[wolfman]

And even if there would be and decent signal at the CGs DIN
its still only mono for ADPCM and CDA as only pin B1 is sending that
those signals back from the IFU.

So there should be CDA on the Coregrafx? I am confused right now...