Traduciendo paso 5
Replace the fuse. Insert transformer power cable to PCB.
Since the Amp did not turn on, check the power out on the transformer. It does show 12V DC. Reconnect it and turn the Amp face forward.
The Amp uses a 6.3mm input and output jack. Apply a sound source to the input. Still no sound from the Amp, it is time to check a bit deeper.