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Old 11-21-2018, 07:41 PM
Evitzee Evitzee is offline
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Default MA7000 problem .... can Autoformers leak?

I've had an MA7000 integrated in the system since they first came out in 2008...absolute perfect function and reliability. No issues. It was their biggest integrated when it came out at 250w/ch, all LED lighting, five band equalizer, etc. Two weeks ago I was walking over to change CD's in the Mac SACD player and the amp clicked off. Odd, and the red led light was off, no power. The next day I pulled the fuse....BLOWN. H'mm, not a good sign but maybe it was a fluke. Put a new 8 amp, 250 volt slo blo fuse in, reconnected the power cord and got the red led light...great. Pushed the button and the fuse immediately blew again and now a snap-crackle-pop back by the fuse area. Dang. I left it for about a week until I could wrestle the 98 lb beast off the credenza with the help of a friend and got it into my SUV for a trip to the authorized service center 85 miles away. When the tech was pulling the amp out of the vehicle this afternoon I noticed that there was an oil looking substance staining the right side of the chrome chassis right below the autoformer. It was not there yesterday when the amp was loaded in the vehicle. The tech didn't think it was coming from the amp but there was absolutely no liquid in the vehicle that could have leaked on to the chassis. It was the consistency and color of motor oil. Can the tar substance in an autoformer degrade and separate over the years and start leaking? I did a search here but couldn't find anything along that line.

I'll have to wait for the diagnosis from the shop but I now believe the autoformer has failed.....hope not too much damage has been done if that is the case. Any thoughts or experience in this area for this kind of problem? I hate lugging a 100 lb lump around for service....a hard weight to handle except with two people and the amp sits on a 46 inch high credenza....so it has to be lifted up and down to the service cart.

Thanks.
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Old 11-21-2018, 08:05 PM
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Curios for sure. I would think the transformers that are encased in tar would not be the issue. The amount of heat it would take to remelt the tar would be extreme and the color would be much darker. Some capacitors are oil filled. Perhaps a capacitor blew or came apart?
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Old 11-22-2018, 01:07 AM
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Ampteks Ampteks is offline
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I would suspect a bad cap causing your problem and mystery substance. Curious to know as well...
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Old 11-22-2018, 08:47 AM
1KW 1KW is offline
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I would trade it in for something new, seriously time for a upgrade
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Old 11-22-2018, 11:17 AM
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Agree with the others above - impossible for the substance to be connected with the Autoformers. A leaking cap is the likely culprit here.

It's probably too late now but I would have recommended the unit be placed upside down to help prevent the oil from migrating into the chassis until it can be serviced.
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Old 11-25-2018, 12:48 PM
Evitzee Evitzee is offline
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Haven't heard anything from the service center yet but you are probably correct, a bad cap which would explain the sound it made when the power was applied. Didn't see the oily substance until the tech pulled it out of the SUV, perhaps the vibration and jostling of the 80 mile trip hastened the dispersion. Anyway it's in their custody now. I'll report back once I have the damage report. Is it normal practice to just replace the failed cap or should they all be done? Don't want to have to bring it back anytime soon.
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Old 11-25-2018, 01:01 PM
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An MA7000 seems awfully new to warrant a replacement of all capacitors for what is likely a manufacturing defect in the one that is leaking. If the rest pass visual inspection, I'd probably just have them replace what needs to be replaced.
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Old 11-25-2018, 01:51 PM
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Agree too with your assessment. But maybe the labor is not much more and I think the caps are to much money so maybe do all of them while they are in there?

I think even on older working amps etc it is a good idea to make work as good as they did when new by re-capping. Sure is not the same as maybe newer better tech stuff etc, but $Vs$ sometimes it makes good sense to draw the line somewhere and recap the units.

Now if you can get the parts and have the skill set of other like a jdandy etc aka hew repaired a JL sub, then you are really $$$$s ahead. But still non the less I think that several of the Macintosh shops like I think audio classics etc can do this for you.
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Old 11-25-2018, 02:05 PM
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Well that's certainly the OP's call but there's little doubt more labor will be involved. Certainly wouldn't hurt to get an estimate for both levels of service. It all depends on how many caps are in an MA7000.

Hard as it is to believe but all the main caps are still original to all 4 of my McIntosh power amplifiers which range in age from 45 - 34 years old and all continue to exceed factory spec.
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Old 12-04-2018, 12:02 AM
Evitzee Evitzee is offline
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Heard back from the Service Center today.....as expected a power capacitor blew up. The parts and labor for the capacitor weren't too bad, but it created a mess on the circuit boards which will require a lot of labor to clean up. A couple of weeks before it is ready, no problem as I will be out of pocket for the next three weeks. They said it was unusual, but not not that uncommon, in other words ' sh** happens'. Let's clean it up and get it back to functioning specs.
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