Macintosh LC no sound

[NickNick]

Greetings!

I am a long time reader, new member and first post. I think its fantastic that there is people who are into these awesome machines and there is a site totally devoted to this. Awesome! I can remember my first taste of a Macintosh Computer it was when I was in fifth grade. I first saw them when fourth grade finished up, as I peered into the computer room connected to my classroom to see Macintosh LC after Macintosh LC; all with their covers off. That was it I was hooked. Fifth grade I finally got to use one. Ever since then I have had an interest in the pizza box mac's. I just think they are a cool little machine with a rather small foot print. Plus I can play all the cool games on them.

My problem is that I have an macintosh LC that I won off ebay. I recapped the machine myself thinking it would resolve the sound problem. No go. I washed it with rubbing alchol and a tooth brush, still nothing. I can not see any visiable damage to anything on the mobo, any of the chips or anything. The head phone jack makes no sound either. The only sound I hear is a clicking from the speaker or head phones when I am playing around with the head phone jack. I did manage to hear a faint sound from the machine with the head phones half way in and half way out but only on one side. Never through the speaker. Any thought would be greatly appreciated as I really am not to sure what else, but the sound chip being broken, could be the issue.

Thank you for your time and have a great day.

Nick.

 

[mcdermd]

The first step should be to double check your work and go hunting for rotten traces around where the capacitors' electrolyte leaked.

 

[Trash80toHP_Mini]

. . . and salutations! Welcome aboard, Nick.

 

[uniserver]

there is a bunch of 10 uf 16v caps that go bad over near the sound chip.

download/file.php?id=2774&mode=view

they just need to be replaced.

no sound or squelching sound is very common on the lci lcii lciii

 

[olePigeon]

Also, make sure the contacts are clean where the motherboard and speaker assembly touch. Not sure how you can check to make sure the speaker is good, though.

 

[mcdermd]

I think that's a long shot as audio through the headphone jack is also faint. It's also probably worth suggesting that you inspect the headphone jack for debris or corrosion fooling the computer into turning off the speaker output.

 

[NickNick]

Evening!

Thank you all for your reply as well as the warm greeting; it is greatly appreciated.

I have checked over the board numerous times; even using a flashlight to see if I could see any break in the traces. I never see any but that would make sence. Is there anything in particular I should be looking for other than a broken trace. Any discoloration or such like that? Also...you just might be on to something there too Mcdermd as, this is the only way I have ever heard the speaker produce a noise is by inserting headphones into the plug. With the plug all the way in like they should be I get nothing no sound. With them half way in and half way out I get very very faint sound and only on one side. If I can recall I did read something on here before in regards to some other member having to replace or remove the audio headphone jack for some reason.

Yes! Your pictures have been an immense help with all the re-caps I have attempted. Made it quite easy to walk in to Chester Electronics here in Kenosha and get the caps. THey unfortunatley only sell the regular caps. On my first LC III re cap I got to use three caps like the one the boards came with as they had three on hand.

The speaker was the first thing I tested and it worked. In my experience with fixing electronic gadgets I have learned to always test the speaker first. I have been burned by the speaker before by not testing it first only to find out it was it all along.

 

[NickNick]

I still am tinkering with this LC and still no luck. I no longer get the popping sound from the speaker with the head phone jack but, with powered speakers and the Mac's volume on max, I get faint, very faint sound. Its either the head phone jack is messed up or the sound chip is shot. I have no other idea what else is wrong. It works perfectly otherwise. Its just that sound is one of the best things of 68k Macs. I just wiped its HDD and installed system 7.5.3 on it.

Thanx all for your input.

Nick.