14-07-2022, 09:32 PM
Dynamos are fairly easily to test on the car. Take a wire from both the D and F terminals on the dynamo, connect them together and then test with a voltmeter when the engine is running. The voltage should rise to anything up to 15 volts ir more as the engine speed increases.
However, given your previous comments regarding the ignition switch, I would see if there is a poor contact in that first. Try wiggling the charge/lighting knob and see if that brings the charging circuit to life. The dynamo field windings earth out via the charging part of the switch, either directly (Winter) or through a resistor (Summer). If they are not earthed, you won't get any charge.
However, given your previous comments regarding the ignition switch, I would see if there is a poor contact in that first. Try wiggling the charge/lighting knob and see if that brings the charging circuit to life. The dynamo field windings earth out via the charging part of the switch, either directly (Winter) or through a resistor (Summer). If they are not earthed, you won't get any charge.