Mk1 mini minor, no spark

[MMM1965]

Hi, hope someone can help, my mk1 mini positive earth started mis firing, i took distributor cap off (points ignition) cleaned rotor arm and cap terminals, replaced and ever since i have no spark. Checked for spark at end of ht lead from coil, nothing there. I have 12v going to - terminal on coil from ign switch and 12v at + terminal. As soon as I connect wire that goes to distributor from coil, voltage at + terminal drops to zero, doesnt make any difference if points are open or closed. I have replaced points and condenser, inspected all wires in distributor,
no difference. Can anyone point me in right direction here please or have a guide how to fault the ignition system please? Many thanks

[Daz1968]

Have you checked the insulation washers on condenser

[MMM1965]

Thanks for reply, do you mean the little plastic washer under where condenser connects to points?

[Daz1968]

Yes that’s the one I was referring to.

[111Robin]

Points open, ignition on, LT lead to distributor disconnected, should be 12v at coil positive. If not the coil primary windings are at fault. Repeat with the LT lead connected. If no voltage this time there is a short to earth inside the distributor, either the insulating washer or the points wire insulation causing a short. Repeat with points closed (if previous test shows no faults) , should read zero. If not then the points aren't closing or are dirty.

[MMM1965]

Thanks all for your help, so much appreciated. Terminals from condenser and LT wire on top of instead of under nylon insulator, doh! Earthing it out! Ive only had minis for 32 years, still learning.. thanks again.