All those equipment not found faulty at the same time.
MCH-300C7 at 2015
AVP-18 at 12-2015
HD-AVP just right now.
For AVP-18 I have contact distributor in Hong Kong, they claimed no parts and needed to contact Taiwan but no feedback after that. Fine, I go for HD-AVP, unfortunately, the same problem occur. I have connected my Stereo Int. Amp on the same source, it runs over 3 years without problem, so I don't believe there is power issue in my home. Of course, I don't power up both Int. AMP and Multi-Channel AMP at the same time.
I just contact distributor for repairing my HD-AVP, wait their reply on nearly repair center.