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Color Classic no sound output via internal speaker or headphone out but issue is NOT analog board.

Verault

Well-known member
So I have two color classics. One I recapped both the logic board and analog board a couple years back and it works fine. The other is a machine I have been getting piece by piece. A friend gave me a color classic chassis with a broken LC550 board and no rear cover and I very recently got a color classic board. The board had very minimal leakage from caps. No leakage from battery. The board would power on as is when I got it but no sound.

for testing purposes I used my known good recapped board in the uncapped color classic case and it boots up and has sound via the internal speaker (also used the non sound board in the recapped Chassis,, still no sound). I figure its just a cap issue so I recap the board. Still no sound. No sound via headphone out which is puzzling.

I did some tracing on the goog and bad board to look for possible breaks but found nothing. Both connect to the IC in the same way. See attached photo:
IMG_20220324_132701.jpg
Using the block diagram on this document: https://powercc.org/downloads/files/Mac Color Classic.pdf
I am assuming the 343S0129-01 IC is what is called DFAC2. Is this the culprit? Is the IC dead?
 
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bibilit

Well-known member
The DFAC is the sound chip, can be bad or simply goo contaminated. You can remove the chip, clean the board and chip legs and put it back.
 

Verault

Well-known member
Thanks bibilit. I just wanted to make sure to exhaust all checks prior to doing that. I do have one spare off a bad board I can use to swap I just wanted to make sure there werent any "known things" to check first.
 

Verault

Well-known member
Well it turned out that the 343S0129-01 DFAC2 chip was in fact bad. I took the one from a bad LC550 board and installed it into the Colormacintosh and I now have sound again. I did check to make sure there were good solder points on the original chip before removing it. It was perfect... It must have somehow fried.

But anyway.. I now have sound again. What could have blown out that IC?IMG_20220328_125619.jpg
 

Plasticoat

Active member
With no sound chip on the board, it will fire up from soft power on keyboard, but will not go further than a grey screen, no cursor.
 

Verault

Well-known member
Ok thats where I am at. Complete grey screen (with the dfac2 installed). See this color classic had a bad DFAC2. I removed one from a bad LC550 board (battery and capacitor bombed). I got sound but not via the headphone jack. I removed the chip to make sure of no bridges but no change. I did notice the DFAC2 was super hot.. Well now I am at a grey screen. Not sure if I left it alone with no headphone jack if it would have kept working. To late to tell now.

Where can I source a replacement DFAC2? that was my only one. Man I am really upset by this.

The chip as a TI logo with numbers 9328xn
And Apple part number 343S0129-01
 
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Plasticoat

Active member
Well sound is important, I’d call it a win, however if you really are set at the headphone jack working,

LC III boards onwards to early PowerPC use the same chips etc, bad boards on eBay are a source
But cannot be guaranteed they are working.

you may be able to acquire one from someone here for a postage cost.. good luck
 

Verault

Well-known member
Thanks, Ill make a posting for one.

I only own one LCIII and it works fine, wouldnt want to sacrafice it!
 

Verault

Well-known member
Well sound is important, I’d call it a win, however if you really are set at the headphone jack working,

LC III boards onwards to early PowerPC use the same chips etc, bad boards on eBay are a source
But cannot be guaranteed they are working.

you may be able to acquire one from someone here for a postage cost.. good luck
So funny thing. I am just working on my LCIII and it also has no sound.. I dont know if this is new or I never noticed. But it does not have the same sound chip it has a 343S1069-A S Anyone know the differences in these chips? Are they interchangeable?
 

Plasticoat

Active member
Sure are, different manufacturers , but they do the same job.

what is more worrying is that lately the failure rate on these sound chips is high.

unfortunately nobody Has come up with or suggested a reason for this, or if there are modern chips that could do the same job
 

Verault

Well-known member
YEah, the 343S1069 has less pins and is a slightly smaller package.

I now have 3 confirmed machines with failed sound chips. This IS a problem. My color classic sound chip has completely failed and now the machine only boots to a grey screen so without a new sound chip the machine is dead in the water.

This is a pandemic and I only see it getting worse. I have had to replace serial controllers and SCSI controller IC's on macs they can still be found. But these custom Sound ASICS are impossible to source. I am hoping someone can reverse engineer them and come up with a modern replacement.
 

Verault

Well-known member
Actually on closer inspection the LC III is a 344S1033-B I believe that is the sound chip. ITs a 28 pin package. I am not sure what the 343S1069 is on the LC III but I dont think its sound.
 

Verault

Well-known member
Well I was able to sourcea new 343S0129 sound chip and it fixed my color classic right up. I get proper sound and when I use headphones the sound comes out via the headphones and not the internal speaker.

I still need to find a 344S1033 sound chip so my LC III can have sound again but those are apparently impossible to source.
 
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