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MG MGA - Charging light on

Just converted my A to Neg earth and now there is a problem. Was working ok before

Done everything correctly and repolarised the dynamo, I then found that at tickover the charging light was on and had to blip engine to extinquish light. Gradually the revs needed to keep light off got higher. Took it on a run and when parked the charging light was on with ign off , i started the engine and now thats it , its stuck on when engine running regardless of engine revs. But when ign off the light goes off as it should.

The dynamo and regulator are both fairly new items , so whats up ?

Thanks Roy
R Mcknight

There is a mod. that can be made to the RB106 regulator by adding a diode in the circuit to reduce contact arcing. I've done it with mine mainly because it was no real trouble as I had a large enough diode available. However, by doing this you make the regulator polarity sensitive and if I ever changed to negative earth in the future I would have to reverse the diode.

It may be that a PO has done this mod. so I would check underneath and inside the regulator to see if a diode has been added.

If there is no diode there or if you know the history of the regulator then I would go through the normal setting up procedure using the workshop manual
m.j. moore

This thread was discussed on 12/06/2013

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