I have a very unusual problem with my home theater system need some help

Hi, I live in Bangladesh I bought my home theater system from Bangkok. I have a unusual problem with my home theater system. My speakers system is Revel Performa 3 and paradigm sub 15 sub woofer 5:1, Mark Levinson 5 channel power amp, Marantz av 8801 surround processor. After using a month suddenly my front Right speakers is not working. It gives a very low ssssshhhhhh sound. You could hardly here it. I have chanced slot (connection) in marantz right to left the speaker was working but now the left speaker was not working giving the same sound. I have checked all five slot (connection) in Mark Levinson all of them working. I thought Only in the Marantz av 8801 front right solt (connection) was not working. I did factory reset, update marantz but nothing is working. So I decided to take it to Bangkok to fix or replace Marantz. But the funny thing is when they connect the Marantz to there system everything was working fine. So they told me to checked the system that I made some mistake. So I came back home and connect the system in my home and everything was working fine. But after 10 maybe 15 days later same thing happened. Front right speaker is not working. This time again I took Mark Levinson & Marantz with me to Bangkok. But again they make the connection and everything was working fine. Again I came home and connect the the system and everything was working fine. After 10 maybe 15 days later same thing happened. Front right speakers was not working. In my country there are no good technician. They don't know what's the problem. Please if anybody can help me solve this problem I would very grateful. Thanks