68kMLA Classic Interface

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Macintosh Classic no sound
Posted by: castroa320 on 2017-04-03 17:41:15 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!
Posted by: MJ313 on 2017-04-03 17:44:48 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.
Posted by: castroa320 on 2017-04-03 17:54:02 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?
Posted by: rsolberg on 2017-04-03 18:13:14 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.
Posted by: castroa320 on 2017-04-04 09:09:42 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?
Posted by: rsolberg on 2017-04-04 09:56:26 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.
Posted by: castroa320 on 2017-04-04 14:58:04 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?
Posted by: techknight on 2017-04-04 15:27:51 the Classic II motherboards are much more rare because a few of them didnt survive the maxell bomb, and the capacitor plauge.
Posted by: Johnnya101 on 2017-04-04 15:29:11 I've got a survivor!!! :0
Posted by: techknight on 2017-04-04 16:51:38 One of the lucky few. They can be had, but they are much more rare than the Classic 1.
Posted by: bibilit on 2017-04-04 23:26:43 , is it possible to upgrade this Macintosh Classic to a Classic II yes, but the rear casing should be modified to suit.
Posted by: castroa320 on 2017-04-16 11:09:25 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 ????
Posted by: Johnnya101 on 2017-04-16 12:01:08 Caps. Probably at least...
Posted by: castroa320 on 2017-04-16 13:59:27 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!
Posted by: Themk on 2017-04-16 14:02:11 The capacitors on the Classic and Classic II are notoriously horrible. :-/
Posted by: rsolberg on 2017-04-16 16:51:52 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.
Posted by: castroa320 on 2017-04-17 05:52:04 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?
Posted by: BadGoldEagle on 2017-04-17 07:30:51 which caps should I replace? The little round ones that are around the board? These ones 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.
Posted by: rsolberg on 2017-04-17 15:54:46 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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