Need McIntosh service advice

Several years back I purchased a McIntosh MA7000 solid state Amp from a reputable online dealer.  The Amp is in mint condition. I used the amp for about 6 months and it worked great.  The amp began over heating on the left channel.  I emailed Mcintosh service and they said the problem was the output circuit.  I took it to an authorized McIntosh repair shop. They keep it for about 5 months and fixed it.  I used it about 6 hours and the left channel overheated again.  My concern is that the authorized repairman did not have enough expertise in a beastly amp like the MA7000.  Any thoughts?