MC2100 repair. Scratching and popping.

JoNate

New Member
Hi, thanks for reading.

I have a MC2100 that is scratching and making the occasional loud pop in the right channel only. I want to repair it myself. Where do I start.

Thank you!
 
It sounds to me like a transistor issue. There are dozens in this amp. First you'll want to isolate which section it is in by swapping which board is going where by process of elimination. Once you know which board or card it is located on, look at the schematic to try to figure it out. I have used freeze spray in the past to isolate which transistor is causing the issue to good effect, but that can fry other components in your amp and definitely nuke your speakers, so be careful.
 
You could do that, but new ones may not sound like the old ones. I bought a bunch, and replaced only the needed one in my MC50. I have extras now for my new MC2105 I'm picking up next week.
 
That might not be the end of it. Sometimes it is a failed or out of spec resistor or cap or some other part that is the root cause of something like this. Finding the culprit and then examining the schematic to see what is in the circuit nearby (electrically) can lead you to the root of the problem.

Good Luck.

Shelly_D
 
The amp is over 40 years old. There are a number of us who daily restore these to try to keep them performing to spec for another 40 years.

I have one on the bench right now that was improperly repaired in the past with the wrong parts and would not meet specifications when bench tested.

If you do not want to have someone,who knows what they are doing, repair it correctly it would make a great trade in towards a newer model or one that is already restored.

It is a McIntosh, it will always retain it's value if it is repaired and or restored correctly.
 
Good point, c_dk.

What do you think something like this is worth it's current condition (really good physical shape)? What would it cost to have the amp gone through completely?
Just gathering thoughts for the big picture.
 
Labor rates vary all over the country, wish we could charge per hour what lawyers get, but then again they do not have to work around live voltge that can stop your heart and we do know the pen is mightier than.......electricity.

If the main filter caps are good parts, cost is usually south of 75 to 100 dollars. Labor for a MC2100 restore is usually less than 4 hours at your local professional service labor rates.

Audio Classics and McIntoshaudio often have MC2100s for resale on their websites, that would put them in the position of establishing prices I would think.
 
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