i recently got my amplifier repaired and brought it home. i had to back to the place that i got it repaired at because i forgot to pick up my a/c cable. when i brought it home i tried to plug it into my amp and it would only go in 4/5 of the way even though it fit in the socket okay. is there any way to check if i got the right cable or should i go back and ask if he has it?