[The Philpott]

Must admit i need to have a think about this, a bit tricky without the meter in front of you.. Ian's better than me at visualising circuit faults from a distance.

The rectifier, if faulty, can be replaced by (four) germanium diodes (eg OA91) but they're temperature sensitive so the leads need grabbing with pointy pliers when soldering, to wick away the heat. (A three handed job unless you've a purpose made heatsink clamp)

dave