I had the same problem and had to send my unit to New jersey for repairs. the only authorized service company for the McIntosh units. The repaired the unit just fine. The name of the company is Panurgy OEM, 973-625-4056. They also upgraded my MS 300 to the MS 750 capability. They take a little while to repair and aren't very good in keeping you up to date on status, but if you don't mind contacting them routingly, they are the only ones authorized by McIntosh to repair the units.
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