Looking at the switch from the side will reveal the split pin which secures the knob to the switch. Removal of the knobs and the two bolts which hold the front plate to the switch panel will give you a better idea of the state of the switches and brass tracks. Removal of the ammeter terminal screws will reveal the countersunk screws which hold the ammeter in the panel. Releasing the nuts behind the switches will release them note their position before removal-they are handed. If the brass tracks are broken I've soldered heavy gauge copper wire across the breaks although I seem to think one of our cherished suppliers now supplies new ones. The best thing for cleaning the contact surfaces is a glass fibre burnishing tool, which modellers use, don't get the glass fibre particles get into your skin or eyes.

Thanks to you all. I must remember to label all the wires going into the panel- they are all black & unmarked! And take photos.
D

Location: Stratford upon Avon

Tony Betts can supply a new main brass track.

David

Thanks for the advice. The assembly came apart without problem & all the parts were intact! I now understand why it feels as if there are more than three positions. As you move from one point to another the dimple briefly is in contact with both terminals, it then makes positive contact with the target point.
Now to wire it all back together.
One further question....when the car was rewired in the 80's all the wires he used, except for starter leads, are 28.030 (28 strands each 0.03mm thick)This appears to be rated at 16amp. Is the considered opinion that this is enough? The wire from the battery to the B terminal on the ammeter concerns me as also does the dynamo output cables. I know that there is not much, but....?
David

Location: Stratford upon Avon

Just to (maybe) put your mind at rest, David. In it's original specification the car's entire electrical load, excluding that of the starter motor, would not have exceeded 16 Amps. The maximum safe output from the dynamo was approx. 8 Amps.

Ian Mc.

Location: Shropshire

That was encouraging!
Well it is all back together, wires connected & the lights work 100% correctly!
I have converted back to negative earth & need to get a new positive terminal over the weekend, then wheels back on & see if the dynamo still charges (& the ammeter reads the right way round!)
David

Location: Stratford upon Avon