Before revision: For example some tuners, usually only pins 1, 4 and 2 are required for audio signal, other ( 3 and 5 were used to send power supply to the tuner U usually DC, as AC may cause hum, tuners usually having low power requirements).
After revision: For example some tuners, usually only pins 1, 3 and 5 are required for audio signal, other ( 2 and 4 were used to send power supply to the tuner U usually DC, as AC may cause hum, tuners usually having low power requirements).