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    MC-2155 +15v/-15v power supply board part overheat

    I am trying to remember the first units Mac used these IC type voltage regulators in...might have been in the MAC4100, certainly soon thereafter. So as part of routine restoration, and having seen them fail in a number of ocasions, replacing the smoothing caps has become SOP. You still need...
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    Mcintosh MC2300 Rebuild

    Under the NY shut down rules who know at this time, phone always worked before. The 15003 has been the device of choice since the 80s, still is, but does have a smidge more gain than the originals so a little more sensitive to oscilation. Central semi still makes the predrivers, the heat sinks...
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    Mcintosh MC2300 Rebuild

    There is also a predriver, driver, and output transistor mod than Terry shared as inside info with me years ago. Made a lot of sense to me but since it was his trade secret it is his choice to reveal. Jeffs79 and I have expanded on his trick to experiment with other driver transistors for the...
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    MC-2155 +15v/-15v power supply board part overheat

    Well you have implied that one polarity is running hotter than the other. So a place to start would be to compare the two actual draws. Thar regulator circuits have been used for decades by Mac enginees in lots of different units. I have seen failed ICs ( Mac categorizes the regulator...
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    MC-2155 +15v/-15v power supply board part overheat

    Oh and lastly, this has nothing to do with the power guard circuits other than I believe the red lights blink along with the count down circuit. The PG circuits are on the driver boards and work exclusively with the output stages and input stages.
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    MC-2155 +15v/-15v power supply board part overheat

    Parts of this board, specifically the voltage regulator circuit will run warm by the nature of their design.....what is too warm or hot I do not know. However measuring the current draw on the regulators might give insight to why one runs hotter than the other as would the voltage drop across...
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    Mcintosh MC2300 Rebuild

    You will have your work cut out or you. Suprised there is no duct tape or bailing wire under the hood...... Have you searched the forum for the numerous MC2300 posts? Most all of your questions should have been already covered in them.
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    Mcintosh MC2300 Rebuild

    Lots of pictures of the unit in it's current state might let us see what has been done correctly or possibly short cutted to keep the show going on. A proper bench test would also be in order to see where you are starting out.
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    McIntosh MAC 1900 Receiver - Short Somewhere on Outputs

    Most techs would use a pair of multimeters setup as ammeters in conjunction with a variac to explore for excessive current draw...... A dim bulb tester is a nice tool for the toolbox when hitting garage sales or after a major rebuild to minimise possible issues either missed or created by the...
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    Using MC2200 with L54

    There should be two holes in the case bottom that match up to two clip nuts in the amps bottom cover. They accept a sheet metal / wood screw type thread, MUST explore, research and be careful about screw length. The screws would have come in the standard screw packet included with each unit.
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    Clueless eBay seller, ...

    Need to keep the reviewers employed....
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    Clueless eBay seller, ...

    I have posted in the past my (our) attempts to extract from Gow and other principles at McIntosh euphoric descriptions of the sound of their audio equipment. Their unwillingness to jump on that bandwagon drove any number of golden ear audio sales people, reviewers and owners crazy...... It...
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    McIntosh MC2215 Power Guard issue

    This whole thread is mistitled....... The OP had a issue with the power supply's regulator circuits and it appears you believe you do also. Best to start a new thread focusing on what concerns you have? Power Guard is a whole seperate circuit design which is indicated in use by the red lights...
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    MR78

    Again none of this matters until he purchases a second Mac unit and needs to find a matching cabinet. As to Modeferri and what I gathered from guarded conversations with a number of Mac principles I think it could be inferred that RIM did not play well with others. As the market demands changed...
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    MR78

    Particle board........very early c8 and such might have been plywood. Again the vast majority of cabinets were made by the OEM speaker cabinet suppliers and they used particle board.
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    MR78

    I will have to look into my stash of cabinets and see if I can produce some pictures. However with the bias you have already shown toward the slant leg style, even when it is not period correct to the unit, I would not be suprised that you would find any other to be wanting. What Tony and his...
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    Glass Faced MC2500!

    Every time I moved a MC2500 I was thankful for the front handles, moving one without them makes me shudder just thinking about even twisting one around on a shelf to attach speaker wires. This glass front unit would need some sort of hand holds but threaded inserts on the top to accept eye...
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    Woofer removal on McIntosh ML-10C speakers

    It is a black window glaze type material......could well be linseed oil based.
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    MR78

    Improper or at least Incomplete cabinet information Seacliff. McIntosh cabinets were built by the companies that OEMed the speaker cabinets, so they varied over years as the speaker cabs varied in their finishes. They basically always made 3 sizes of different height. Since the MR 78 came out...
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    MC2255 click at startup through speakers

    Yes you are. You are fixated on a quick and easy shotgun fix without diagnosing if the "problem" is a problem or just a benign issue that you need to chalk up to aging parts. Have you looked at the pulse on a scope or even to see which speaker driver is pulsing or whether it pulses in or out...
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    MA6100 issue

    Most common issue with monitor circuits is hooking them up backwards......out to out and in to in and corroded switch contacts. Everybody hooks up a tape loop incorrectly at least one time and partial disassembly and Deoxit D5 application is always a given with the switches every few years.
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    Glass Faced MC2500!

    It would not be the only time that a experimental prototype slipped past Fran's shipping authorization..... I do wonder how long before the glass broke assuming the MC2500 was used in a typical comercial installation. We one time had to use a Mc2205 in a roller/ ice rink for a emergency system...
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    McIntosh MX110Z and C20 (later model)

    Well let's have some fun with this......... I have posted in the Mac forum a conversation I had with the president of McIntosh over dinner, soon after he returned from visiting his friends in Japan. Gordon told us of their museum grade McIntosh collections that sat under glass to be taken out...
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    McIntosh XR3 drivers

    Twii We all know you detest Roger's speaker designs for McIntosh, I believe you use modified 45 year old Bozaks from the days just after McIntosh and Bozak had a falling out. The Morel drive units Roger spec'ed for the replacement are certainly high quality parts but his crossover design...
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    Power Guard in MC2105??? Has anyone ever seen this?

    The external limiter box prototype the factory sent us for evaluation was a utter failure, sucking the dynamics put of the music. It's reliance on the diode avalanche effect to brute force yank down the output set back the acceptence of the PG circuit that had been implemented with the MAC4100...
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