McIntish MC162 and C15

How come suddenly I don't get sound from right side amp? Since a long rest, I reconnected the system, but there was no sound. This is the first time I had such problem. I have done all kind of testings, but can't figure out what is the problem. I switched the cables and found the speaker and the amp were okay. I would appreciate it if you can give me any advices or ideas.

Although it has been long time since I had the amp and preamp, I used them only a few hundreds hours. They have been sitting in my music room, but they look like new. Been dry, no fungus, no dropping, no dent, nonsmoking, no pets, no impacts, and many more etc.
I had a C15, nice pre and certainly worth repairing .....give McIntosh a call they still support it.  

I have C15 as my preamp, for the power amps I use two MC2205’s driving a big JBL Studio monitor bi-amplified. After an extended non use period I fired up the system, the high end was working fine but the low end was dead, the solution was simple, I started turning various knobs on the dead power amp back and forth and boom it started working just fine, try this before you consider more drastic measures, who knows it might just work.

My guess is that build up of corrosion in various moving parts can cause this. 

Thanks vanes and  oddiofyl.

Vanes, mine was exactly the same as your situation, an extended time of non use.  I tried switching cables, amps and speakers, and turning knobs. Also, cleaned all contacts even though there were no corrosions. I realized the amp and the speakers were working. I am suspicious of either pre amp or its connections. All components, cables terminations are like new, and so it is very frustrated.

Oddiofyl, I called McIntosh and was informed that technician should open the components to find out the problem. 

One more unscientific observation on the longterm non use corrosion, houses that have natural gas appliances are particularly problematic when it comes to affecting contacts, the gas appliances produce a tiny amount of sulphur based corrosives in the air that corrode component contacts, here I am talking about very longterm and slow effect, but I have seen this happen many instances.

Yes, I can imagine so too. And I checked them all out again but found no corrosions. All contacts are very clean like new condition. The room where the components are is upstairs with no access from the gas or sulphur (I think) as the gas heater is in the downstairs garage and the gas range is in the other corner of the house downstairs. 

It is frustrated, and I have to contemplate what to do: not to use the McIntosh, to repair the components, to sell them or to replace the components.

Anyway, thanks for your kindness to try to help me, and sorry for misspelling your ID previously.