Hello, my Harmon Kardon AVR 310 has been malfunctioning- the output goes off and on every two seconds or so....on for two...off for two, etc. Doesn't matter what source of input, mode of Surround Sound, speaker selection, how long it's been on or off, where it's plugged in, etc. I bought it used and it worked well for a brief period, then I had to have it serviced because it quit working altogether and all they would really tell me is that they re-soldered some of the connections, but it worked fine for the better part of a year. If anyone knows what I might check for myself I would be grateful. I'm not sure I want to spend another wad of money- the first repair was $175 and, of course, it's beyond warranty. Is this a common problem with this kind of receiver? Thanks, Steve