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NEC TG-16/TE/TurboDuo => TG/PCE Repair/Mod Discussion => Topic started by: Bonknuts on March 18, 2012, 06:04:41 AM

Title: ADPCM sound problems for the SuperCDROM attachment
Post by: Bonknuts on March 18, 2012, 06:04:41 AM

The sound levels are barely audible for ADPCM, although red book and PSG is fine. I didn't see anything specific about this in searching the forums. Anyone have any experience with this? Is this a resistor or cap in the mixing circuit for ADPCM to the others?

Title: Re: ADPCM sound problems for the SuperCDROM attachment
Post by: Keith Courage on March 18, 2012, 06:58:55 AM

This can be caused by bad caps and sometimes you can get lucky and make it work again by changing them. However, as of late I have come across quite a few DUOs that have other shorts, bad resisters, or broken traces on the board in that area causing the problem. I would attempt to change the audio caps first and see what happens.

Title: Re: ADPCM sound problems for the SuperCDROM attachment
Post by: Bonknuts on March 18, 2012, 10:09:35 AM

Crap. I took it apart, but it's more consolidated that I had originally thought. This is gonna be a pain the ass :/

 Edit: Some details: there's a daughter board that plugs into the main board. The daughter board is right next to the AV output. There's a four 4558's, one bu4053bf, and one M51131L.

Title: Re: ADPCM sound problems for the SuperCDROM attachment
Post by: Keith Courage on March 18, 2012, 12:58:56 PM

Yeah, those super cd drives are a pain in the ass to change caps on. You can pull off the top portion of the daughter you board to get to the caps better. Here is the total capacitor chart link for it http://www.pcenginefx.com/forums/index.php?topic=9544.0

Title: Re: ADPCM sound problems for the SuperCDROM attachment
Post by: BlueBMW on March 18, 2012, 04:47:56 PM

Yeah, SuperCDROM2s are no fun to do caps on...  Granted they're not a Laseractive Sega PAC, but they're still up there as far as annoyance level.

Title: Re: ADPCM sound problems for the SuperCDROM attachment
Post by: Bonknuts on March 23, 2012, 09:31:08 AM

Ouuu :3 Thanks for the link. I'll see about replacing the caps on the daughter board first.