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MG TD TF 1500 - TD cut out

Does any body have an idea what would cause the regulator (RB106) cutout points to open and close,I tried another regulator and this did the same.
The cutout closes normally as the revs rise and the regulator controls the voltage OK (except when the cut out opens).
It is not speed or load related just random.
The car was off the road for 36 years and the owner is keen to use it again.
Ray Lee
TF 2884
Ray Lee

I ran into a similar problem several years back. I was driving myself crazy trying to adjust the cutout. I eventually found that a my freshly charged modern battery was showing well over 14 volts. I believe that this was telling the voltage regulator to cut out and my red ignition light would glow. I parked the car and left the lights on for a bit and ran the battery down to where it was showing around 13 volts with no load. After this, the problem did not resurface. I think that the battery was starting off a little overcharged and the generator (dynamo?) would give it a little extra bit of "glow" and this would fool the regulator.
Steven Tobias

Ray -- I would suspect the voltage (shunt) coil of the cutout to have a broken (corroded) wire. Makes a connection when cold, opens when it warms up. Try another regulator. See if it does the same thing. If it does the same thing it's not the cutout.

Put a voltmeter on the yellow wire (from the dynamo to the regulator). If that shows voltage only when the cutout closes then it's the dynamo.

Let us know what you find.
Bob Jeffers

This thread was discussed on 10/05/2010

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