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McIntosh - Hints and Kinks

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Scottsmrnyc,
I had an idea this am as the wife would like to have Christmas music on during a family gathering this evening.
I looked up the input voltage on my C32 inputs, and thought to use my multimeter to read what I was putting out at what setting on my PC volume control.
Unfortunately I could read voltage with my postive on the RCA male parts of ajack, but when I grounded the negative to the shell the voltage just dropped down.

So maybe I would have to do this while the output is actually running something, I don't know.

Maybe someone will chime in on what I was doing wrong, and how to do it.
If possible.
Jeff
 
Hello All:

I noticed last night on my MC 2205 amp that when you are facing the unit the rear right "heat sink" is warm to the touch and the rear left is cool, no heat. The amp is working in stereo and both meters work independently and I can turn the gain down seperatly so I don't understand why only one "sink" would be warm any thoughts
 
MC2205 has a bias adjustment on the driver board, correctly set the heatsinks will get slightly warm at idle (no output). The bias setting procedure requires an AC amp meter in the AC line, procedure is described in the service manual.
 
MC-30 component questions

I've got an MC-30 which I'm completely rebuilding since it was in pretty sad shape. For the resistors: what type is best? Stick with the carbon composition or go to a newer type? Capacitors; new orange drop OK? How do you get the transformers out of the potting compound in the can? It seems to melt with a heat gun (but slowly) so I was thinking of sticking the whole can upside down in some boiling water or an oil bath. Reasonable?

Conrad
 
The tar melting point is 600dF, neither hot water or oil can safely melt it, I have used a hot plate, question is why. If you must remove the potting use the heat gun from the inside to pull the tar from around the transformer, then pry the core out.
The resistor type is up to you, I personally use carbon or metal film for temperature stability. Orange drops are OK but may give the 30 to modern a sound, I mix types to mellow the sound, paper foil or PIO in at least one stage.
 
I need to remove the transformer from the can since the wire insulation is badly cracked (power transformer). I'd like to replace it as close to the winding as possible and have the cans powder coated while they're empty.

Conrad
 
Have seen the covers removed by hanging the transformer by it's leads and using a torch to heat the cover, do it fast and don't catch the tar on fire are my thoughts.
 
MC2002 RT Channel cuts out to protect no protect light

Dear experts,

ok, the mc2002 is now a problem...on occasion at any volume the rt channel goes quiet, if I apply a solid smack to the wood cabinet, presto it's back...

Any guesses, it could be an old RT channel interconnect gone bad or the output of the MC 4xxxx eq where I use it OFF and just the Bass controls.

Maybe I should swap the EQ for the other backup unit?

Maybe a new interconnect for the rt channel?

Curious...

John
 
Terry, I have a MQ101 which sounds distorted when put on the tape loop on my C2200 pre-amp. I tried inserting it between my tape deck and the pre- and I still get the same results. Does this unit has a history of caps drying up? I don't have the SM so I can only guess at this point. Any help is greatly appreciated.
 
No real history on the EQ101, a transistor or two and a power supply filter, only had 2 on the bench in 3 years.
 
I've searched high and low and can't find it, but I swear I recall seeing a bit of discussion on how to take apart and troubleshoot those pesky IF cans. The tech who sat on the 113 for a year before returning it "unable to fix- part not available" said that the 19KHz transformer (Mc part 162-055) was bad. How do I get it out of the can, and which pins are which?
 
mrz80, thanks and a very Happy New Year! You are right Terry. This unit has been very reliable and I am the second owner. It is the first time it has broken down in its history. Let me go through and post my findings on it. Thanks once again gentlemen.
 
mrz80 said:
I've searched high and low and can't find it, but I swear I recall seeing a bit of discussion on how to take apart and troubleshoot those pesky IF cans. The tech who sat on the 113 for a year before returning it "unable to fix- part not available" said that the 19KHz transformer (Mc part 162-055) was bad. How do I get it out of the can, and which pins are which?
Click to expand...

There was a discussion some time back regarding MX-110s and I/F cans with where they were rebuilt to eliminate a small silver-coated cap in the can's bottom. Might search with those elements.....I've got an MX-110 with the symptoms that will need attention at some point.

Cheers,

David
 
Well, as it turned out, it was dead simple to get the can off the transformer; it was just crimped to the sides of the base. When I got it apart, this is what I found - all the wires leading from the coils to the base were snapped off. (see the picture)

I just got a quote of $400.00 and 2 months' time to have it rewound. That seems a trifle steep; I could nearly buy another 113 for that! :)

I'm wondering what to do now. I've browsed until my eyeballs dried and can find no source online for even a near match of this little guy. I'm guessing that someone a lot more adept than I at resonant circuits could cobble up something in the way of a design for a substitute.
 

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MX110 never had a lit dial pointer, if the glass does not glow from the edge lighting it could be a bad festoon lamp, bad filter between the festoon and the glass, or tired glass that the lettering is getting loose and does not pick up the light from the glass. If the letteing is getting loose do not attempt to clean the inner dial glass as the lettering can fall off with any touch.
 
Thanks Terry. The glass glows, dimmer setting works lettering is intact no bubbles. I just did not know if the pointer was suppose to light up.
 
So Terry, what *is* your approach to dealing with one of these units (like my 113) where that 19kc xfrmr is damaged like that (all the coil wires broken)?
 
Either figure out the wiring, ohm the leads, and wire them back, or order a new one from the factory. You would be surprised what they still have in stock, I just ordered a 162-031 19K coil for a MR73, retail at $6, better than telling the customer his tuner is scrap.
 
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