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MG Midget and Sprite Technical - Control box burn out

I have a midget to look at because the battery was going flat after a drive of just 10km or less. The battery has just been changed to see if that was the issue, and no improvement resulted.

Going to check and adjust the dynamo control box I discover that the left hand coil (the one with the adjusting screw) was looking decidedly sorry for itself, and a light touch with a screwdriver caused it to crumble - it is completely burnt through.

The question before I fit a replacement is : What needs to be checked and fixed before sending another one to its grave?

dominic clancy

I saw over on the MGA site they suggest that you fit an alternator.
You can get alternators that are bodied as dynamos. Up to recent times these have been mega expensive. One of my members, at last years Classic Car Show, bought a cheaper version 139 (show discounted to 100) from Bad Boy Classics. He tested it over 2500 miles, on his 1275 Frogeye,on our September Miglia Tour with no problems.
You can read a report of the Tour at
Alan Anstead

If Alan's solution isn't an option here is a link to a website from Moss with instructions for a voltage regulator prior to fitting.

And here is a link for a PDF file for Generator and control box tests.

Hopes this helps.

pjw Seezink

I agree, now is the time for a modern alt with a built in electronic regulator... single wire is the easist to install wont regret it

Prop and the Blackhole Midget

I have no experience of one but there are firms that supply / convert voltage regulators to electronic.
Alan Anstead

I'm grateful for the replies

I have bought a replacement unit from Moss. If this burns out then I will switch to the same Accuspark alternator I have in my own car. The reason I didn't go for that solution is that the car is still +ve earth and has an electronic tachometer that I will also have to remove and modify if I decide to go that route, plus switching the battery around, the diode on the fuel pump........

and as the Accuspark alternator has only done 5k km in my car, I'd like to see a bit more use before I start retrofitting other cars with it.
dominic clancy

And the Moss unit arrived this morning and after a call to Moss went straight into the trash

One terminal loose in the box, another bent, and all loose

Made in India printed proud on the box

We'll see what turns up next week.....

dominic clancy

Here in the U.S. they've been running ads on TV about how good things made in India are. Mostly aircraft items, seats, engines, etc. If that control box is a sign of their quality.......
Martin Washington

At least 1 800 telephone computer repair customer support from idia is super top notch

(Im assuming)

Prop and the Blackhole Midget

This thread was discussed between 10/11/2015 and 21/11/2015

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