737-300/400 TR3 Disconnect Relay
Why is this relay labeled TR3 when in reality it is disconnecting the TR1 from TR2 and separating the two DC buss-es during the glide slope capture or when the bus transfer switch is switched off. I realise that TR3 can back up TR2 and TR1 via a diode under normal operations however this is separate to the TR3 disconnect relay.
Cheers mangatete.