good heavens shaun, thats an old one, the psu circuit isnt in the the manual but this is from memory, dc to the smoothing block is not present until it receives an on from the signal board. I take it the standby light is lit, if it is, marked on the board there will be pwr on from the main board to the psu. Once this feed to the psu is present, if the psu is working it will energise the relay and mains will be applied to the bridge. I suppose you could bridge the relay contacts to determine if the psu works or not, i take it the relay does not energise if the standby button is pressed either on the set or remote. If the relay does not click it is likely to be a signal board problem but we binned all ours years ago. make sure your stb6 is correct and reaching the signals pcb and let me know. I love challenges. see you soon,
tony
