Reviving an old full wave rectifying valve

[Brianc]

The bases are normally held on by shellac and a filler of some sort - sawdust or similar. This can be softened with thinners. The wires need to be un-soldered by heating the tips of the pins and using a sucker or braid. Once the wires are free, the base can be pulled off. As laurence says, only two diodes are required and these go between pins 1 and 3 or 4 (the heater pins) and between 2 and the same heater pin as the first. Do NOT join pins 3 and 4 together or you will short out the secondary on the power Xfmr. You must examine the wiring to see which heater pin to use. It must be the pin to which the reservoir capacitor is connected. I hope I have explained that well enough!