broomball

My '78 280z 2+2 would not start yesterday even with a jump. Not a noise from the starter or the open door buzzer or anything. Dead! A week ago this happened and it started with a jump then worked as if nothing happened. I immediately turned off the car an it restarted again and again. But yesterday it didn't respond to a jump. I took off the leads to the battery, which is new from last summer, and cleaned them then tried to start it again but no luck. I tried hitting the solenoid with no success. I did notice that the amp meter did slightly move negatively as I turned on the key but that stopped after trying to jump the car. Any help would be greatly appredciated. Lou