McIntosh MC2152 power amp technical question


My MC2152 suddenly acting up. When I use the XLR input the right channel makes popping sound when power off. To make the situation worst, the sound coming from this right channel is slightly lower compared to left channel which resulted in uneven sounds: left sound louder than right. IF I use the RCA interconnect the sound is fine and no speakers popping noise when powered off. I can settle by using the RCA interconnect and move on but i want to use the XLR input for better sound quality.  

Could it be the XLR right channel input connection defect? Or the electric board holding the XLR right input is defect?  Any technicians here in the community, your inputs would be greatly appreciated.  

thank you in advance for all your suggestions/help. 
kentrent
mrdecibel is of course correct.  However being in my late fifties, I harken back to the McIntosh of old.  I have owned a MA-6100, C-26, C-27, C-28, C-29, MC-2300, MC-2105, MC-2505, MR78 and none of it purchased new.
When I bought my MC-2300, it was nearly 10 years old, had a little noise in one channel. I called Mac, they sent me a shipping crate, a box and instructed me on how to pack it.  (I paid for those materials).  They repaired the amp and provided notes and test results.  It had a bad filter cap (about the size of a beer can) which they replaced at no cost.  They also replaced the good caps so that everything was a matched set. My 2300 was an early run, so my cap issue was a known problem which was remedied in later production.
So, because of that there was no cost to me.  That is the McIntosh that I am talking about.  First rate products, impeccable build and stellar service.
They are still the ones I would send my amp too, but their response to you clearly indicates that the old way of standing behind their products is gone.  I guess that it being “Mac” I expected more, I think anyone who’s buys Mac expects more.  
@normansizemore that’s exactly i would expect from Mac too. To stand behind their products and people buy an expensive product  they expect stellar service.   Like luxury cars and Toyota.   I’m disappointed in Mac.  Prolly wont buy anything from them anymore.   
Hi kentrent,
I'm sorry to hear you're having trouble with your MC2152 amp.
Whereabouts are you located?
My advise would be to start with the dealer that sold you the MC2152. It seems that it was only a few months since you bought it and they should be able to help even if you bought it used. Once it goes in for service you would get a repair estimate and the chance to authorize work based on that estimate for which there may be a small charge, you should not be surprised by a large bill.
A dealer may also be able to represent you better to McIntosh, usually things go a lot smoother once the dealer has confirmed the problem. I know it doesn't help you but probably over 90% of all reported faults are in fact not issues with the product itself hence the process to have a local dealer verify it first to make the best use of limited and precious service resources. Having said that I've never seen any noticeable delays in responses to my requests for answers, part requests or other types of requests.
My advise would be to try to build a relationship with a local dealer. McIntosh do not sell their products directly to customers, only through authorized retailers and dealers who all receive in depth training to support the products.
Jeremy Bicknell
Basil Inc. Audio Systems
@basilandco i bought the amp used from another seller.  Not from an actual McIntosh dealer hence why I didn’t get warranty. But im disappointed that warranty doesn’t follow the amp.  Its follow one owner and thats it not transferrable.  Now i left with a defective amp that doesn’t work as it should.  
Classe warranty is transferrable, but they were brought by Japaness conpany. Hope Mac can stay healthy and long. anyone heard this new set Mc2152/C70?  can give some review? since I am thinking to buy it if they are good. Thanks!