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#1
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I have a McIntosh 2100 that was performance certified in 1976 at a
clinic. Now it needs service - one of the channels intermittently drops. Do they still have those free clinics? |
#2
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On May 14, 1:00*pm, Bob Simon wrote:
I have a McIntosh 2100 that was performance certified in 1976 at a clinic. *Now it needs service - one of the channels intermittently drops. Do they still have those free clinics? Been a while since I heard of one but you can find people to service them. The free clinic wouldn't have fixed it anyway. |
#3
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#4
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![]() "Bob Simon" wrote in message ... On Wed, 14 May 2008 10:56:00 -0700 (PDT), wrote: On May 14, 1:00 pm, Bob Simon wrote: I have a McIntosh 2100 that was performance certified in 1976 at a clinic. Now it needs service - one of the channels intermittently drops. Do they still have those free clinics? Been a while since I heard of one but you can find people to service them. The free clinic wouldn't have fixed it anyway. There's a guy in town who has a good reputation. A few months ago he replaced some components in my NAD preamp/tuner and it cost around $125. This was more than I expected but I haven't paid for electronic service for 10 years so I really don't know what this work should cost now. Do you think there may be an advantage to sending it to McIntosh for factory service? As I understand it, the transistors have to be matched. $125 for anything over and above a quick cleaning is cheap. Shops generally are charging $50-$75 for a diagnosis/estimate these days. If you've got the cash, sending it to the factory for servicing GENERALLY guarantees a certain quality of service and availability of parts which your around-town guy might (or might not) be lacking. We've all heard horror stories though, so it's not a lock on perfect results. Sending it back to the manufacturer almost always involves a lengthy period of time too. If you have a knowledgeable, competent technician I don't think you're going to do any better at the factory. You can buy output and driver transistors in matched sets, a PNP mated with an NPN with similar gain characteristics. You'd only ever need to replace a transistor if it was bad, it's not a preventative maintenance item to replace any. If your channel cuts out randomly, it COULD be a transistor, but it's more likely a cold solder joint or dirty switch in a piece of vintage gear. Dave |
#5
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![]() "Bob Simon" wrote in message ... I have a McIntosh 2100 that was performance certified in 1976 at a clinic. Now it needs service - one of the channels intermittently drops. Do they still have those free clinics? Unless the input level control is dirty, there really isn't much inside the 2100 that would cause a channel to be intermittent. No switches, no relays. Your problem could well be elsewhere in the system. Mark Z. |
#6
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On Wed, 14 May 2008 12:00:03 -0500, Bob Simon
wrote: I have a McIntosh 2100 that was performance certified in 1976 at a clinic. Now it needs service - one of the channels intermittently drops. Clean the switches and controls. Pay special attention to the speaker on/off switch. If cleaning with Caig MCL doesn't make it operate reliably, replacements are available from Mc. It's also a very good idea to remove the driver cards and to clean their contacts. Just a very, very, very light coating of Caig on the board contacts and re-insert. Do they still have those free clinics? Sadly, Davey O'Brien has been gone these several years. Nobody else was willing to do the gig. All good fortune, Chris Hornbeck "I have a gift for enraging people, but if I ever bore you, it'll be with a knife." -Louise Brooks |
#7
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Bob Simon wrote:
I have a McIntosh 2100 that was performance certified in 1976 at a clinic. Now it needs service - one of the channels intermittently drops. Do they still have those free clinics? In response to Mark Z's reply. Sometimes the card edge connectors of the driver boards can also cause noise. They can be cleaned, but getting to them is not a task for someone who does not feel comfortable doing serious repairs, as a lot of the amp has to come apart. (DON'T use any abrasives on the contacts, just lacquer thinner on a swab will do, clean ONLY the card edge, not the socket on the chassis. Work the card in and out of the socket a few times to wipe the contacts.) I've also seen the input differential transistors get noisy, and these should be well matched if replaced. They are much more likely to cause a noise problem than the output transistors. a few other parts on the driver boards can also cause problems. Ask the repair shop if they can gain match (beta match) transistors. If they seem to have no idea of what you are talking about, take the amp elsewhere. If there is ANY significant DC at the terminals (I'd say more than 10 mV) then the amp needs service. Also, one channel running considerably hotter than the other is reason for concern. The amp should be a bit warm after an hour or 2 with no signal, but not hot. Sending it to McIntosh is certainly a safe choice, but shipping could be expensive depending where you are. You might want to look at the McIntosh web site for an authorized servicer in your area. Regards, Tim Schwartz Bristol Electronics |
#8
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On Thu, 15 May 2008 10:44:17 GMT, Tim Schwartz
wrote: Bob Simon wrote: I have a McIntosh 2100 that was performance certified in 1976 at a clinic. Now it needs service - one of the channels intermittently drops. Do they still have those free clinics? In response to Mark Z's reply. Sometimes the card edge connectors of the driver boards can also cause noise. They can be cleaned, but getting to them is not a task for someone who does not feel comfortable doing serious repairs, as a lot of the amp has to come apart. (DON'T use any abrasives on the contacts, just lacquer thinner on a swab will do, clean ONLY the card edge, not the socket on the chassis. Work the card in and out of the socket a few times to wipe the contacts.) I've also seen the input differential transistors get noisy, and these should be well matched if replaced. They are much more likely to cause a noise problem than the output transistors. a few other parts on the driver boards can also cause problems. Ask the repair shop if they can gain match (beta match) transistors. If they seem to have no idea of what you are talking about, take the amp elsewhere. If there is ANY significant DC at the terminals (I'd say more than 10 mV) then the amp needs service. Also, one channel running considerably hotter than the other is reason for concern. The amp should be a bit warm after an hour or 2 with no signal, but not hot. Sending it to McIntosh is certainly a safe choice, but shipping could be expensive depending where you are. You might want to look at the McIntosh web site for an authorized servicer in your area. Regards, Tim Schwartz Bristol Electronics Thanks to all for the good advice. Bob |
#9
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McIntosh no longer runs free clinics for a variety of reasons, one being
that Dave O'Brien retired several years ago and sadly passed away last year or so. I'd give all the switches a good cleaning, reseat all connectors and cards and just for good measure go over any suspicious solder joint carefully with RMA flux snd reflow it. Then clean carefully. -- Message posted using http://www.talkaboutaudio.com/group/rec.audio.tech/ More information at http://www.talkaboutaudio.com/faq.html |
#10
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![]() "BretLudwig" wrote in message lkaboutaudio.com... McIntosh no longer runs free clinics for a variety of reasons, one being that Dave O'Brien retired several years ago and sadly passed away last year or so. I'd give all the switches a good cleaning, reseat all connectors and cards and just for good measure go over any suspicious solder joint carefully with RMA flux snd reflow it. Then clean carefully. -- Message posted using http://www.talkaboutaudio.com/group/rec.audio.tech/ More information at http://www.talkaboutaudio.com/faq.html There is also a resistor on each driver board which needs to be resoldered. It's fairly large and is pretty obvious when you see it. Mark Z. |
#11
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On May 27, 8:21*pm, "Mark D. Zacharias"
wrote: "BretLudwig" wrote in message lkaboutaudio.com... McIntosh no longer runs free clinics for a variety of reasons, one being that Dave O'Brien retired several years ago and sadly passed away last year or so. I'd give all the switches a good cleaning, reseat all connectors and cards and *just for good measure go over any suspicious solder joint carefully with RMA flux snd reflow it. Then clean carefully. -- Message posted usinghttp://www.talkaboutaudio.com/group/rec.audio.tech/ More information athttp://www.talkaboutaudio.com/faq.html There is also a resistor on each driver board which needs to be resoldered.. It's fairly large and is pretty obvious when you see it. Mark Z. It is probably not a good idea for most people to be reflowing solder joints unless they have been identified as a problem and that person has some experience soldering. The rest of your advice may well solve his problems and are within the capabilities of just about everyone. |
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