Control Box testing - help pls (2 bobbin RB 106/2)

I’d be very grateful for any insight as to what next to do. I’ve a replacement control box (new old stock ) which I have fitted which hasn’t solved the problem & before i write-off this ‘new’ control box i thought i’d try and learn a bit more about these old things…

printed off instructions for testing generator & control box and have given dynamo clean bill of health and the D & F wires too. I think I MUST BE DOING SOMETHING VERY STUPID BUT I CAN’T FIGURE OUT WHAT IT IS
Here’s where i come unstuck …
with engine stationary and A1 & A leads pulled off control box and connected to each other , I put a voltmeter between A and E terminals on control box it says YOU SHOULD READ AROUND 12V . I read about 0.1 v
Instructions diagnose this as break in earth i.e. poor earth to E . However, when I run a new good earth to E it’s the same !
can’t be right can it!
Incidentally , rather than join A1 & A it recommends putting a piece of card between the contacts to isolate the battery but I’m damned if i know which contacts it is referring to … LH bobbin or RH bobbin.
This is a steep learning curve for me and I’m not yet finished I know!
don’t suppose there’s much chance of that MOT i was aiming for tomorrow unless one of you has the magic?
RichC

Hi Rich

Luckily my box has been fine so I have not had a lot to do with it.

Have a look at mg-tabc.org/techn-up/lucas_c … arging.pdf

Previously on my Minis I have just replaced them if I suspected they were faulty, there are a few new ones on Ebay for under ?25.

Good luck

Jason

Hi

Just another thought; I may be teaching you to suck eggs but are you wiring the control box up correctly? Isn’t your car is Positive earth?
First wiring diagram in the Workshop Manual (on the disc I gave you) is the one you need.

Pages 30-35 of the Workshop Manual tells you how to adjust the box.

Jason

After linking A1 and A the voltmeter goes on D to check the voltage the cardboard is for the left bobbin and you check amps between the linked wires and A,
Neil

Sorted!
workshop manual makes it very clear & Lucas diagnostic intructions found on web very helpful .in the end it was a questiion of adjusting the screws for both regulator & cutout to get the correct readings . So nice to see the ammeter kicp up into the positive for the first time
RichC