My new McIntosh 2105 blowing Fuses!!

Well I picked up a 2105 yesterday at an estate auction in an untested state along with a MR74 and a C26, a Teac 3300S and some University speakers all for $600.00.

There was no way to test the units since they were brought out from a basement and sold from a big flat hay wagon in the middle of a field. But I thought for the right price I would take a shot, even though the 2105 did not have a fuse in it.

Sure enough, today I hook up the amp, along with the other units, and it blows a fuse as soon as the power is switched on. So I do a little research on the old infoweb and it sounds one possibility is a short somewhere in the driver section or bad driver boards. I remove the covers and pull the drivers as suggested and power the unit up again. Fuse blows instantly again. Well, I am thinking major problems here. Then I get to looking around and I notice that the right channel driver board has had a resistor replaced (see pictures pretty severe burns to board). This leads me to believe that the problem is in the right side. I get to looking around and I see a green wire that is smashed up against the chassis sub structure (see photo's), and it has exposed wiring.

OK, this is were the story ends for now. I am out of fuses and need to run to the hardware to pick some up. In the mean time what do you guys think about this? Do you think by powering the unit on and blowing fuses that it could have caused other damage to the unit?

I will get back with an update after returning from the fuse run. In the mean time chime in with your thoughts.

Don't keep blowing the fuses, when the fuse blows, yes something is shorted out, you don't want to cause any further damage by repeatedly blowing fuses.

At this point it could be a number of things.

Could be a bad Bridge Rectifier.

Could be dried up main caps if the unit has been sitting for a long time (least likely though)

Could be and is most likely shorted output transistors and/or drivers usually accompanied by some other issues.

600 bucks for that haul is pretty good!! You're ahead of the game already.

If you are not a competent tech, then I would get all of it into somewhere like Audio Classics or Terry Dewick and get the units repaired and restored to operational condition.

When you pull the driver board, that disconnects the outputs.

Rig up a "light bulb variac" and it will save some time and fuses. Separate the hot side of an extension cord, get a small standard lamp socket and wire it in the the open section of the cord. Since it's in series with the amp, the lamp will light up brightly if there is a short in the amp. 60w or so incandescent lamp.

Murray

Too nice of unit to mess around ........time to break down, spend the money because it deserves to be done right, and hire a tech.

Burnt resistor shows the negative pre driver has most likely failed and the amp will need the service bulliten update with subbed parts. Since some outputs are shorted, they are hot right off the supply, they all will need to be replaced with most likely the resistors. A recap is what 15 years overdue....It will need some major service to get it back to spec.

There was a reason it was put in storage in the basement.

kevzep said:

If you are not a competent tech, then I would get all of it into somewhere like Audio Classics or Terry Dewick and get the units repaired and restored to operational condition.

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This purchase is a common problem I have had many times when seeing a classic Mcintosh for sale somewhere. He wanted a $600 system. He didn't want a $1000+ system by the time he got through (although we don't know how high he was willing to bid). He didn't state whether the MR74 and C26 were working normally. Possibly more money. I just bought a $450 MC2200 and it will cost me at least $200 more to properly restore it (this includes fixing the service problem).

Owning restored vintage McIntosh is not an inexpensive proposition......but certainly cheaper than restoring cars or motorcycles.

I would like to hear from JMARLEY as to his intentions when he bought the equipment. Did he cross his fingers and hope he could take it home and just plug it in or did assume and budget for a restoration, either on his own or from a pro. It would be interesting to know what he mentally set as a bidding limit during the auction. It's easier to justify a refurb if there was a big spread between the two numbers. I have never been to an estate sale but I assume everything is sold as is with no opportunity to plug it in.

i agree its worthy of a proper tech to fix it up . save your time in saving up for the invoice ...

Well, after isolating the wire from the chassis and replacing the fuse it has blown again. I does blow instantly and I hear a slight buzz when it does so.

As far as my intentions on purchasing the unit goes, I had purchased with the hopes of using the entire set up. I, of course, was hoping that everything was in working order but was buying also knowing that there was a good chance I would have to put some more money into the system, which I am not opposed to doing. As far as one poster saying that the unit was stored in the basemant because it had a problem, that is not actually the case. The entire system was at one time being used in a "man cave" it was not actually just being stored in the basement. The basement was fully finished, and quite nicely I might add with a nice pool table, large plasma tv and very nice bar along with a nice poker set up. The actual estate, which was not part of the auction, was listed at 1.6 million. which in rural Indiana is a quite nice estate. Now as far as how long the system did have issues, that I do not know.

The other units, C26 and MR74 are both in nice working condition as all three units had the wood cases around them and the front glass is in great condition on all three. I have tested the other to units by hooking the up to my Yamaha CA-2010 and they work as they should.

I guess what I need to do is find someone that can do that proper work on the amp, since I am definitely not a tech capable of working on such a unit. I can do just some basic parts replacement and soldering if I know exactly what the problem is. But as far as tracking down the possible problem that is beyond my skill level.

Anybody familiar with a good reliable service tech in North East Indiana or even central Indiana, say around the Indy area?

By the way. I was willing to bid up to $1200 for all three pieces, with the idea they might need some work. The speakers and reel to reel were just throw ins and not part of the equation. Here are some pics of one of the University speakers. Not sure what the model # is, I couldn't find a badge on the outside of the cabinet that gave the model number.

jmarley7 said:

Anybody familiar with a good reliable service tech in North East Indiana or even central Indiana, say around the Indy area?

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Why don't you contact c_dk in south east Michigan