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castroa320

Macintosh Classic no sound

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Hi everyone. I recently pulled out my Macintosh Classic from the closet so I can play around with it. I acquired it on a eBay auction a couple of years ago. The Macintosh has a 500 mb hard drive with 4MB of RAM installed. The little machine runs great but lacks sound. No startup chime or anything but boots right into System 7.5 that I installed fresh less then an hour ago. I go into the Control Panel for sound and it still plays nothing even though the volume is on max. I've plugged in my external speaker and it makes very little sound. I've even tried out the Control Panel for sound as well with the speaker. I've read on here and, on other sites, that washing the motherboard can resolve problems with leaking capacitors and all that. My motherboard seemed really clean but I still went ahead and gave it a little bath and let it dry for about 24 hours. I plug it in and I'm back to square one.  :(  I know that this problem has been talked about on here and other places on the internet but I want to know any other solutions other then recapping(if possible). I have no experience with soldering and all that and don't know any LOCAL places where I can get my motherboard recapped. All those services like MacCaps seem great but I'd prefer a local repair shop or something if thats the worst case scenario.   Any tips will be appreciated!

 

 

Thanks!  

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 I want to know any other solutions other then recapping(if possible).

 

No other solution, unfortunately. Classic logic board and analog board caps are notorious leakers. If you post where in the world you are, someone may be able to offer you their services.

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No other solution, unfortunately. Classic logic board and analog board caps are notorious leakers. If you post where in the world you are, someone may be able to offer you their services.

Do you(or anyone) know of any services in the Detroit,Michigan area that recap motherboards? 

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I do know that the last time I had a board out to Charles (maccaps.com) he was based out of Southfield, MI. If I'm not mistaken, that's a Detroit suburb.

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If i have to get the Mac recapped, which capacitor is it? I know its good to get all of them recapped because they leak overtime but i would like to know which one it is. Is it on the board that has all of the power supply stuff or is it on the actual motherboard? 

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There are eight surface mount capacitors on the Mac Classic logic board that will need to be replaced. By the time that sound goes wonky, usually all of them are leaking. There are seven 47uf 16v and one 1uf 16v caps on the board. They look like little silver round trash can lids and they often leak directly underneath, so the leakage isn't always evident until they're removed. The leakage from these can damage traces and vias on the logic board, so the sooner they're replaced, the better. The power supply and analog board section of the Classic is also worth having recapped so that it can provide stable power to the system and drive the CRT without distortion or flickering.

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There are eight surface mount capacitors on the Mac Classic logic board that will need to be replaced. By the time that sound goes wonky, usually all of them are leaking. There are seven 47uf 16v and one 1uf 16v caps on the board. They look like little silver round trash can lids and they often leak directly underneath, so the leakage isn't always evident until they're removed. The leakage from these can damage traces and vias on the logic board, so the sooner they're replaced, the better. The power supply and analog board section of the Classic is also worth having recapped so that it can provide stable power to the system and drive the CRT without distortion or flickering.

 

Cool thanks. I'll give this a try sometime this week. Hopefully that resolves the issues. Another question though(off topic), is it possible to upgrade this Macintosh Classic to a Classic II? Like buy a motherboard from a Classic II and put it in the original Classic? They both have the same case from what It looks like. Am I wrong? 

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, is it possible to upgrade this Macintosh Classic to a Classic II

 

yes, but the rear casing should be modified to suit.

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An update:

 

So I managed to buy two motherboards for this machine. One MB is for the original Classic and the other for the Classic II. For some reason, the new Classic MB produces a louder, but very quiet at the same time sound. I plug-in my Classic II motherboard, it produces sound normally. Now the only problem I have now is that the motherboard Makes this high-pitched noise and I'm afraid to leave it on for a long time. Note that the other motherboards don't have this problem. They simple don't make sound. So now, I have 2 problems ????

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Caps. Probably at least...

Most likely be replacing the caps. One strange thing is that when I connect a external speaker to the motherboard, it still does that high pitched sound through the external speaker. Thankfully, it's not something that will blow up the whole machine! 

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The screeching is very reminiscent of capacitor failure too. My guess is that the boards are in different stages of failure. Some seem to exhibit audio issues first, others show stability issues, and some just stop turning on suddenly without the user noticing problems first.

 

EDIT: years ago, my Colour Classic started intermittently making a high pitched whine. I thought my tinnitus was getting worse until I figured out it was coming from the Mac after it warmed up significantly. I disconnected the speaker, somehow thinking it was responsible and the noise stopped. Of course as soon as I plugged headphones or speakers into the output jack, there was the awful noise, just horrendously loud.

Edited by rsolberg

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The screeching is very reminiscent of capacitor failure too. My guess is that the boards are in different stages of failure. Some seem to exhibit audio issues first, others show stability issues, and some just stop turning on suddenly without the user noticing problems first.

 

EDIT: years ago, my Colour Classic started intermittently making a high pitched whine. I thought my tinnitus was getting worse until I figured out it was coming from the Mac after it warmed up significantly. I disconnected the speaker, somehow thinking it was responsible and the noise stopped. Of course as soon as I plugged headphones or speakers into the output jack, there was the awful noise, just horrendously loud.

See i've never did any kind of soldering in my life. I'm gonna start with a old CD-ROM drive I have to gain some skill. But after that, which caps should I replace? The little round ones that are around the board? 

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which caps should I replace? The little round ones that are around the board? 

 

These ones

Macintosh%2520Classic.jpg

 

And you should clean all your boards in soapy water before putting the new caps on.

 

 

The screeching is very reminiscent of capacitor failure too. 

Just have a listen:Mac Classic.mp3

That's my Classic II. Haven't got round to recap this baby yet. Next thing on my list.

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Haha that Mac sounds like a kettle coming to the boil! My CC was this horrendous tone that changed pitch occasionally. It was somewhat higher than 15kHz and many other people couldn't hear it, further convincing me it was my tinnitus at the time.

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These ones

Macintosh%2520Classic.jpg

 

And you should clean all your boards in soapy water before putting the new caps on.

 

 

Just have a listen:

That's my Classic II. Haven't got round to recap this baby yet. Next thing on my list.

Thats how mine sounds! I think I'm going to take a risk and solder it myself since I have two other motherboards incase one catches on fire or something after recapping  :b&w: . But one more question.... Do the new caps matter how they look? I found a couple of 47uf 16v and 1uf 16v capacitors and they look different. Not sure if they have to be the can looking ones or not. 

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