Hi all,
I'm trying to get an a12 to run on the shed floor to see if it is okay to go into a mini, however I cannot get any spark out of the coil.

It has 12V to the + terminal on the coil but no power from - terminal (with points open or closed). There is power from the main terminal on the coil though (terminal from coil to rotor) constantly.

I have checked everything and so far: Ballast resistor is fine, new coil which should be fine, new rotor button and dizzy cap, new spark plug leads and plugs, new points which have been gapped.

Coil is getting 12 volts but it seems that when the points are closed the coil is not earthing through the distributor.... any ideas anyone? Have I missed something obvious?

Also, engine is safely secured on the floor so no need for flaming.

Cheers,
Jim.

Replace the condensor

Cheers
Dave

I agree condensor or points normally.

Thanks guys,
Will order one tomorrow and give it another go.

if you put 12V to the coil + terminal, you should get some V from the - terminal with the points open. If not, the coil is bad.

Condensor won't cause this problem.

there is really no need to order a condensor,unless your miles from nowhere, they are available off the shelf at any supercheap/repco/autobarn

As accurate as a diagnosis is from the other end of the internet, I had exactly this problem about a month ago, and after first replaceing the coil with no result, it was the condensor.

12V at coil +, 0V at coil -. Replaced condensor, all good.

Cheers
Dave,

If you pit power into one side of the coil's primary winding terminal, you should get power out of the other side.
You can use a test light or multimeter when testing the coil alone [disconected from other wires]

From the description I'd say a coil test would be an advantage.

Now I am quite confused.

Following your advice Dodgeman, I did a coil test which showed 12V in and 12V out with coil disconnected from the distributor. When I reconnected the distributor however it dropped to 0.4V out.

It has a new condenser now too, along with the new coil, new rotor button, new dizzy cap, new ht leads, new plugs, new points.....

Does anyone have any suggestions as to what could be causing this?

Cheers,
Jim.

All that means is that the coil is acting properly. It should show exactly as you tested.

When the points are closed, the output is at earth level. Well close to it, yours has a slight earth problem.

Run a new wire from the battery NEG to the body of the distriburtor to improve the earth temporarily.

Also confirm that with the distributor connected and engine turned so that the points are open, you still get 12V out both sides of the coil. If not your points are still grounded internally and something is wrong there.