The red/black wire was disconnected but this had no effect. My problem is that the distributor hall sensor does not switch when I slowly hand turn the engine (voltmeter at the correct ignition switch amplifier terminals just shows a flat 10v). I have bench tested the distributor hall sensor and it switched when I supplied a dc voltage of 5V & 10V and turned the rotor arm. So the hall sensor is not at fault. I also used another second hand distributor and the same results occur. I also used another second hand ignition switch amplifier and same results occured. The coil has the correct ohmage ratings. When I first did the tests the volts supplied to the hall sensor was 5V but now it's always 10V. When I measured the volts at the coil it first gave 2 volts then 0 volts (as expected) when I switched on the ignition but now it gives 5 volts then 0 volts. How is this possible?

The red/black wire was disconnected but this had no effect.

My problem is that the distributor hall sensor does not switch when I slowly hand turn the engine (voltmeter at the correct ignition switch amplifier terminals just shows a flat 10v).

I have bench tested the distributor hall sensor and it switched when I supplied a dc voltage of 5V & 10V and turned the rotor arm. So the hall sensor is not at fault. I also used another second hand distributor and the same above results occur.

I also used another second hand ignition switch amplifier and same results occured.

The coil has the correct ohmage ratings. All leads have been checked.

When I first did the tests the volts supplied to the hall sensor was 5V but now it's always 10V. When I measured the volts at the coil it first gave 2 volts then 0 volts (as expected) when I switched on the ignition but now it gives 5 volts then 0 volts. How is this possible?