MC2100 repairs

duder1982

Active Member
I will be receiving a MC21000. Come to find out it the breaker pops, I would love to ship this off to Terry(if he is still in business). But would like to take a look under the hood myself. Anybody have any ideas where to start, once its up and running any mods or anything particular that should be replaced. I figured I might take a whack at rebuilding the power supply, I know some like to maintain the stock look. But for me its about functionality, any good parts recommendation, or where to get a schematic. I think it is coming with a service sheet or brochure. I am kind of excited as this will be my second piece of McIntosh gear I will own.

I am sure there are dozens of threads on everything I just asked, if so then if someone would be so kind to post links to them here.

Thanks.

One last thing is there a good location to obtain new transformer schematic prints, the ones on this look a bit rough. Plus I may need to repaint them as well.
 
I purchased transformer labels for an MC2105 from McIntosh directly (about 10 years ago) so I bet they still stock them. They're of the peel and stick variety.

Terry is still in business and going strong.
 
Most likely cause of the breaker "popping" is a shorted output. At it's age of 40+ years I would replace input and driver board electrolytic caps. If the output failure was catastrophic expect to rebuild driver board to last design spec.
 
I purchased transformer labels for an MC2105 from McIntosh directly (about 10 years ago) so I bet they still stock them. They're of the peel and stick variety.

Terry is still in business and going strong.

Thanks for the info, good to hear Terry is still in business. I will call audio classics as they seem to carry Mc parts, I don't mind peel and stick as along as they look decent.
 
Most likely cause of the breaker "popping" is a shorted output. At it's age of 40+ years I would replace input and driver board electrolytic caps. If the output failure was catastrophic expect to rebuild driver board to last design spec.

I was wondering that, dang now I have 2 McIntosh amps that need over hauled. I think I will do this one from the ground up once I have time.
 
Most likely cause of the breaker "popping" is a shorted output. At it's age of 40+ years I would replace input and driver board electrolytic caps. If the output failure was catastrophic expect to rebuild driver board to last design spec.


After re reading this, this doesn't sound do bad to do. I have driver boards out now, is there a parts list of the latest updates. I figured I would start with that. One other thing I found that the isolator on one of the heat sinks is cracked. Is there a simple replacement.
 
If anyone can answer a question that would be great, on the input board c303c304 are listed as a 470 uf cap, but on mine I have a 680 uf cap installed. Could this be do to a serial number change or is it possible that someone has been in here. What should go here.

All so what has everyone done about the multi section cap c203 is there an alternative I could install. Thanks.
 
Couple more things, if someone has a better replacement for q11-14 please let me know, all so if someone could double check my order here at this link that would be great too, man am I asking alot. I guess I just want to do this right.

http://www.mouser.com/Cart/Cart.aspx

There are some extras for other projects, those are after the 12 output transistors.

Other then the multi section cap
 
Ok I have answered my own question to why I have 680 uf caps on the input board, as these are original to the schematic I have. I have 2 schematics, the original one and the one from Audiokarma database, which I believe may be an updated version. So from that I should order replacement parts as per the updated version. Now I just need to know if the output cards are correct from the AK database.
 
Replace all the 'lytic caps on the input board. The value of that 680µf cap isn't critical (I think early units used 500) and I replaced mine with 1000µf axial caps.

Also, replace all the 'lytic caps on the driver boards. Some odd values. Driver boards are same both sides so can be swapped.

I cleaned out the small filter can cap on mine mainly because I could. Probably wasn't necessary.

Yes, you probably have a shorted output on yours and may also have a shorted whatever transistor on one or both driver boards.

My 2105 is on, playing some tunes right now.

K0QxrD3.jpg


hv3zZJP.jpg
 
I used Panasonic M series caps (2) 100/200v, (1) 150/160v and (1) 68/160v caps to replace the original.

Original is 80/200v, 80/200v, 150/150v, 50/150v.

If it was me doing this, I'd fix the short problem first and then move on to more fun stuff.

Murray
 
I used Panasonic M series caps (2) 100/200v, (1) 150/160v and (1) 68/160v caps to replace the original.

Original is 80/200v, 80/200v, 150/150v, 50/150v.

If it was me doing this, I'd fix the short problem first and then move on to more fun stuff.

Murray

Thanks for the info, I will probably fix the short first. I just want to only have one order to Mouser if I can.
 
Ok back up, parts ordered. I did do as Skippy recommended and started testing all the outputs. So far 1 out of 9 have only tested bad. I have 3 more to test, along with the driver transistors. I have all new outputs, drivers and electrolytics ordered. So the outputs and input cards will all get updated. Meanwhile will continue to look for a good pull from my mc2505 so I can test it out and see if the bad output was the source of my fuse popping. For some reason this mc2100 seems easier then my 2505.

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Can anyone tell me if I should replace this diode, it test good but the chip bothers me. I guess if I have to ask I probably should.

uploadfromtaptalk1403320503208.jpg

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Hello duder1982

Can anyone tell me if I should replace this diode, it test good but the chip bothers me.

this diode looks like the one under the heatsink of driver transistor .
This diode is MCINTOSH part number 070043 and it is a 1N4724 diode

Yes , if I was you , I will replace it :thmbsp:
 
Hello duder1982

Can anyone tell me if I should replace this diode, it test good but the chip bothers me.

this diode looks like the one under the heatsink of driver transistor .
This diode is MCINTOSH part number 070043 and it is a 1N4724 diode

Yes , if I was you , I will replace it :thmbsp:

Thanks for the quick response, another thing if you may. I ordered 2 new driver transistors. But I wasn't able to remove the original heat sinks from the older transistors, is there a way to do this, or do I need to replace the heat sinks. If I need to replace the heat sink, is there a recommended on.

Thanks again, If I can get this unit up and running I think I will have another wonderful amp on my hands.
 
One more thing, if I remove the driver card, and the fuse doesn't blow. Does that mean the problem lies between either the driver card and output stage. From what I understand if the outputs go they take the drivers with them.

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