I have a Pioneer receiver that I recently got in pretty Mint condition. I recently set it up and started listening. I noticed occasionally it will play fine on FM and then the left channel will drop out. I tried plugging in my IPOD with a nice gold plated Aux cable. Same thing was happening. Yesterday I had the IPOD plug in everything was working fine. I went to plug in the power adapter for the IPOD and when I did the channel dropped immediately. Would you think this would be a grounding issue????? The stereos from the 70's only had a 2 prong plug on them. I still have other troubleshooting to do but thought I would ask in advance. Any input appreciated. Thanks in Advance!