3511 dynamo fault

Help. I've got a zetor 3511. I've replaced the dynamo with a new one.This has a + and a - terminal on the side and another + terminal on the back. It is drawing current not charging. I have tried polarising it which has not worked. I've spent all day working on it and I'm going mad. Can anyone suggest a solution other than fitting an alternator which I don't want to do. Thanks, Dom.

Control box ?

I have a 6745 with generator with similar fault. I have just ordered a new voltage regulator pn 3511 5709. Make sure you do not have a broken wire and that your regulator has voltage. There is a piece in the workshop manual on checking the circuit.