no center output on Sony STR-K502P


2013-04-21 3:52 pm
I have a Sony STR-K502P home receiver. While watching a program the other day the center channel stopped working. Prior to that I had recently noticed a clicking noise like a relay switching off and right back on. I am assuming this was one of the blue rectangular relays on the main board. I have taken it apart a couple of times since and resoldered some cold joints but nothing seems to have done the trick. I also placed a non conductive thin layer of foam underneath the main board just in case it was a grounding issue. Should I replace the center channel relay? How do I determine which one is for the center channel and a part number for it. I also read in a forum that my output transistors could be bad. There are 2 for each channel. Again, which ones are for the center channel and how can I get a rating or a part number?