There is no number on it not sure of exact size does say hi dive looked inside two pill I don't know anything about trouble shooting it . But when I put the pre-amp on light comes on but amp power light is partially light also and the rf meter drops a hair with no increase rf . When I put power to amp and transmit light comes on and I can hear relay click put not seem to have increase wattage output. I got this amp new and had it for years always worked fine is it at the end of it's life or is there something I can do with it?