• Updated 2023-07-12: Hello, Guest! Welcome back, and be sure to check out this follow-up post about our outage a week or so ago.

LC III lost sound

Verault

Well-known member
So my LC III doesnt make a sound anymore. I have been trying to find the soundchip to no avail. I was able to get sound back on my LC II by using deoxit and a toothbrush on a couple areas which had some whitish buildup on IC pins. I tried this on the LC III but still no sound.

Board was recapped a couple years ago and has been fine otherwise. Any ideas?
 

MrFahrenheit

Well-known member
I had this problem back in the day. Apple service outlet told me to power on fresh holding PRAM reset keys for 11 restart cycles to clear corrupted PRAM. It solved the problem which quite surprised me.
 

Verault

Well-known member
I havent tried the audio out jack to be honest. I will try that.

I dont use the system with a PRAM battery in it though (and I didnt use a PRAM battery when the sound was still working). Do you think that fix may work anyway? Waht are the PRAM reset keys?

Thanks guys
 

MrFahrenheit

Well-known member
I havent tried the audio out jack to be honest. I will try that.

I dont use the system with a PRAM battery in it though (and I didnt use a PRAM battery when the sound was still working). Do you think that fix may work anyway? Waht are the PRAM reset keys?

Thanks guys

Its possible the PRAM has become corrupt. I’d still try resetting it.

The keys to hold down before switching on are:

Command Option P R

I usually hold half down with one hand, switch on and quickly place fingers on other half before the system skips it.
 

joshc

Well-known member
Try the audio out jack, could just be a bad speaker.

How well was the board cleaned when the caps were done? Could be dirt on the sound chip.
 

Verault

Well-known member
Ok So I tried headphones and I do get sound out via the audio out. There is a hot popping though almost as if there is a short.

I tried the PRAM reset in excess of 11 times and it still makes no sound via internal speaker.

Board was cleaned pretty well. This board didnt have much residue as compared to the LC1's and II's I repaired. The board is pretty clean.

JoshC I tried a spare speaker as well.. I have a small heap of good speakers.. No change with that either.
 

Verault

Well-known member
I did the work. And like I mentioned the sound was working up until this year. Then one day it was just silent.
 

Verault

Well-known member
Ok this is weird. The sound just came back. After about 3 or 4 restarts from doing the PRAM reset. I could be wrong but it sounds slowed down to me but its there.
 

3lectr1cPPC

Well-known member
Did you ever remove the sound chip? Maybe some crud has been lying under it and it’s now causing a short or an intermittent trace/via.
 

Verault

Well-known member
it could be crud, like I said its pretty clean and i used deoxit with a toothbrush and I dont see anything.
 

Verault

Well-known member
Honestly I have no problem removing an SMD IC like this. But my track record with sound chips failing on old macs makes me not want to touch it. Too many color classic repairs and pulling chips on and off. Ill just run it until the issue presents again.
 

David Cook

Well-known member
Follow these steps to determine if there is a problem with the jacks or any of the traces:

Let me know what you find.
 

Verault

Well-known member
Completely unrelated but what is meant to connect the the strange tiny connector at J7? I see this on a bunch of boards and have no idea what its for.
 
Top