Morris Minor Owners Club

Thought I had sorted it! The red charge light would stay on after the ignition was turned off then sometimes it wouldnt go out while driving, so having had a flat battery a few weeks ago I got a new control box from Bullmotif.
That sorted that one out and everything was peachy, tonight the red light is back on when the ignition is switched off and the keys are out the switch.
So I checked the wires to the control box, none have come out, cleaned and checked the dyno wires which were pretty dirty, that hasnt helped.
When the engine is revved a bit the light should go out? It doesnt! Could it be the brushes in the dyno? or a dodgy control box?
Has developed a slight misfire and I wondered if this may be connected.

Any Ideas

If the battery volts are low - it could mis-fire. Yes - dynamo brushes are the next check - although that won't explain the red light staying ON with Ign off - which is a sign of the Reg box having stuck ON. When this happens you must disconnect the battery asap! And have a look inside the Reg box to see if the contacts are stuck shut. If they are - gently prise apart and clean the contacts by dragging a light abrasive through between them.

Thanks,
Theres two sets of points in the box, which should be open? Seems odd that a new box would have the same probs, Ive got a quick disconnect switch on the battery which Ive been using just in case!

Have you checked that the fan belt is tight by trying to turn the fan blades?
When you rev the engine to fast tickover the points in the control box should open and the ignition light should go out and stay out until the revs drop to slow tickover.
Check the dynamo brushes

The main points CLOSE when you rev up ! The second coil 'vibrates' to control the voltage. Both sets should be open when at rest.

I knew it was one or the other, I could not be bothered to check, besides I knew that you would correct me if I was wrong

Thanks, I will check the points, that kinda rules out the dyno.
I did clean the points when I fitted the new box, as a sticker on the part said I should, cant think they would need cleaning again already. The last one lasted 20 years!

No point giving WRONG advice Mike - if you don't know - don't say....... We can all make mistakes - I suggest you go back now and edit your post to correct it....

Ah ha, just checked the control box, the big points on the right are open all the time even when the engine is revved , the smaller points on left are closed when the engine is off.
The charge light now goes out when ignition is off, but will not go out when the engine speed increases. I tried closing the points and they spark but wont stay closed.
Ive wiggled the key in the ignition switch just in case thats a bit iffy but the light doesnt flicker.
This is pretty much where I was at with the old box.
Could it be wiring probs?

Sounds like useless dynamo to me......

Forgive me as I may be wrong here, but I am sure your control box is correct, the regulator points on the left are normally closed, and the cut off points on the right are normally open.

Rev it and the cut off should close, the regulator points will then open, and close quite quickly, they are controlling the field windings, and hence the output from the dynamo, regulating it.

Not closing when revving is either the dynamo or the wiring between it and the box, more than likely the dynamo, moving parts that wear.

Have you downloaded a manual to help check the charging circuit? Here is one,
https://www.google.co.uk/?gws_rd=ssl#q= ... manual.pdf
It covers checking the regulator and dynamo, also it offers advice on checking the whole electrical system of a car.

Thanks,
The points stay open when revved so I will have a look at the online manual

Had a quick look at the manual, looks like Im gonna need a multimetre voltage tester jobby. Bit thin on the ground in the wild west! mmm mmmm
Must be a Cornish tester, the farm next door has some very big hammers!

For everything you will do with a Minor one of the cheap multi meters will be absolutely fine, you don't need anything accurate down to the last millivolt, and they are generally a very useful piece of kit to have around for electrical fault finding.

Meant to say that B&Q used to sell a cheap one, I have one that I leave out in the workshop, my expensive calibrated one that I use for my electronics does not get kicked around the car then.

Geoff

Here you go. http://www.ebay.co.uk/itm/Digital-LCD-M ... 53f1c8bba5

Got a cheap multimeter from the big city (penzance!) Took ages to figure out how the thing works. Battery was a bit down 12.5 volts but I guess it wasnt charging, Dyno was 13 volts and increased with engine speed.
So checked the wiring again and guess what? found that one of the dyno wires in the control box was only hanging by one tiny bit of wire and pulled straight out. So re-connected and the points work and the light goes out.
Im off to eat humble pie, on the + side ive got a shiny new multimeter.
Thanks for the replies.

Well done ! Great success !

Excellent stuff, so the multi meter did its job, helped you diagnose what was not wrong and find the fault.They really are useful to have around.

Glad its sorted out.

Thanks,
looks like im gonna need it, foggy today so used headlights and wot not, managed to loose headlights and stop indicators from flashing!