I have a McIntosh 2105 I bought new in 1967. After all these years yesterday when I turned it on all was fine until I turned up the gain. Then the left channel put out a super loud beating noise. The right channel is OK. I am not sure whether there is any audio from the left channel any more or not. Any ideas about what could be wrong? I am definitely not an electronics whiz. I can solder but I don't really know much more than that. Many years ago I built one of those HK Citation pream kits and it worked fine, but that was just a "paint by numbers" kind of job. My only test equipment would be a volt/ohm meter, a new one but more for car work than stereo.
Any ideas?
Thanks in advance.
Any ideas?
Thanks in advance.
Service manuals are readily available to download - but beware - there is more than one version of the MC2105.
I agree that this task may be best left to a professional, as the electronics involved are quite complicated.
Judging by the number of recapping kits available out there, a good start may be to replace the electrolytic capacitors.
Replacement is not for the uninitiated - note the complexity and the safety precautions in this video:
McIntosh MC 2105 Restoration P2: Let’s Recap The Power Supply - YouTube
I agree that this task may be best left to a professional, as the electronics involved are quite complicated.
Judging by the number of recapping kits available out there, a good start may be to replace the electrolytic capacitors.
Replacement is not for the uninitiated - note the complexity and the safety precautions in this video:
McIntosh MC 2105 Restoration P2: Let’s Recap The Power Supply - YouTube
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My original intention was to add to post 2 :
Hurry before people talk you into recapping.
A Mac of that era fails usually after 40 years,
so you are already in advantage.
Hurry before people talk you into recapping.
A Mac of that era fails usually after 40 years,
so you are already in advantage.
Note that the restoration video I linked to is but one of a series.
The next one is here: McIntosh MC 2105 Restoration P3: Let’s Recap & Test The Input Board - YouTube
Of course, the cause of your fault, which sounds like a form of motorboating, may lie elsewhere than with the electrolytic capacitors.
I am simply attempting to alert you to the complexity of the task.
The next one is here: McIntosh MC 2105 Restoration P3: Let’s Recap & Test The Input Board - YouTube
Of course, the cause of your fault, which sounds like a form of motorboating, may lie elsewhere than with the electrolytic capacitors.
I am simply attempting to alert you to the complexity of the task.
MC2105 has a beating sound
Yes, motorboating, that's a very good description of what's going on. Does that lead to any ideas about what could be wrong?
I'm not in a money state to spend $1,000 or something to get it fixed. Would I be better off selling this one as a "fixer upper" to a technical person?
Yes, motorboating, that's a very good description of what's going on. Does that lead to any ideas about what could be wrong?
I'm not in a money state to spend $1,000 or something to get it fixed. Would I be better off selling this one as a "fixer upper" to a technical person?
I know that motorboating can be caused by ageing decoupling capacitors. Can't swear as to that being the cause in the case of your MC2105. You could look for signs of bulging/leaking electrolytic capacitors.
It could be said you have had your money's worth from this amplifier, and, unless you have the expertise to troubleshoot it, it may be time to move on.
It could be said you have had your money's worth from this amplifier, and, unless you have the expertise to troubleshoot it, it may be time to move on.
P.S. If you can keep the thread going a bit longer, you may eventually catch the eye of a McIntosh expert!
Many thanks for all the replies. I had seen one or two of the resto videos before. They are of very high quality, showing clearly what is being done. It would appear that there are a few tools and supplies a person would need for a complete restoration. The hardest part of all this would most likely be desoldering from the circuit board. I have soldered lots of stuff over the years but never worked with boards before. The maker of the video makes it all look easy. There are lots of vultures out there who want to pay me very little for my two Mc items, wonder what a realistic value for a broken amp might be.
I presume you've been inside and inspected the components, including the electrolytic capacitors, David?
It's just possible that a visible fault may be uncovered by comparing the motorboating channel with the working channel.
Working MC2105s are worth thousands, so yours is well worth some further exploration.
It's just possible that a visible fault may be uncovered by comparing the motorboating channel with the working channel.
Working MC2105s are worth thousands, so yours is well worth some further exploration.
I'm thinking if this unit were to be repaired it might fetch around $2,000 US. Is there any interest among the readers here at say, $750 plus whatever shipping is?