I have an Ameritron AL80B that was working. I started noticing some sporadic issues last year but has finally stopped working. Turns on, tube gets hot and glows xmit light turns on and I hear a click from the relay high/max SWR on my radio when switch on OPR with radio set to lowest output very low SWR when switch set to STBY HV reading 2800 Plate lg 125ish absolutely 0 RF output I've taken it apart and there are no obvious signs of something being burned up. I pulled the tube and it looks like it's in great shape. Nothing looks scorched anywhere. Do my symptoms above indicate anything obvious? What could cause this behavior? What else should I test?