I have a very confusing situation with my radio. It is a 12V replica radio I installed in my 51 F1 truck that is still 6V positive ground. I installed the power inverter for positive ground systems and it comes in with 6.8 V and converts to 12.06 V. With the key on the radio uses .59 A and the radio works fine. If I start the truck with the radio on it works until I shut it off then it wont work. If I start the truck and try to turn on the radio it wont turn on. Only the light comes on but cant change stations and not even static. The amps used jumps to 3.6A and 4A. Macs Auto warrantied the power inverter but that didn't change anything. I tried to disconnect the radio light, speaker, antenna, no change. I disconnected the radio and hooked up an equalizer and the amps were less but similar reaction . Has anyone seen anything like this before?