Known Factory wiring fault in SOME McIntosh MC611 monobloc amps

I own a pair of McIntosh MC611 monobloc amplifiers that I purchased new over a year ago.

Since that time I have sensed that something was wrong and I have been continually trying to track-down an imbalance in my system. I wasted many hours, labour and equipment-switching to diagnose the problem.

Only recently, with the help of the dealer and a technician did I find out what the problem was. In fact it is two problems:

1)

There was a mistake made at the factory, in which plugs from the  input board (J8 & J9) were reversed, resulting in one channel being out-of-phase! (improper imaging/no centre image)

2)

The Single-ended/Balanced switch on the back panel does not function properly. Corrosion from the circuit board coating chemical on that switch causes intermittent problems with the signal and a lack of proper power output of the amp, resulting in a volume imbalance. (which also ruins imaging)

I wasted a lot of time and trouble getting this problem diagnosed, but the McIntosh factory is not interested in making this in a general recall.

So, let's call this a 'Public Service Announcement'. I would not wish for anyone else to go through this trouble, expense and aggravation. I have been told that there is a (secret) Service Advisory regarding this problem, so there must be more of you out there with the same trouble.

However, you will not see any information about it on the McIntosh website! Let it also be known that it will not get detected on a test bench. See test meter readout. Also switching polarity at the speaker will bring out the problem but will also introduce harmonics – due to the nature of the circuitry.

If there are more of you out there, be advised….and I think we should be entitled to some compensation from the manufacturer.

http://https//drive.google.com/file/d/1AkoKtAidGMdQmTH5F2WIP1BHWf-FXkZo/view?usp=sharing