My problem is this. I have a Sony CDX f5700 and a JL Audio E6450 Amp in my boat. The Amp is powered by 4 awg wire at positve and ground. The Power for the Sony comes directly from the power at the amp. When I turn on the head unit the face immediately goes off unless the blue remote amp wire is disconnected or there is a battery charger connected to ths battery. Voltage at the battery and head unit in 12.86v. I had a pioneer head installed with the same wiring and it worked fine. Also, I tried another new Sony head unit, and it acted the same. Any ideas or thoughts will be appreciated.