Your inner brush looks strange. It looks like an outer brush was installed over the framework of an original inner brush. Here's a pic of the outer and inner brushes. Note the larger bracket on the inner brush, held in place by 3 screws .....
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I don't know, maybe what you've got will work fine, but maybe not. Maybe the brush isn't getting grounded as well as it should (it grounds through the 3 screws). Maybe that's why your slap test is weak. You might want to get yourself an actual inner brush.
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Well spotted ..
If I get this right it has now been tested with 2 regulators
Dead regulator? Was leant one by a mate to substitute in and I think it was dead. ( Green windings beside it got really hot after only a few seconds in place, was quick to remove it. )
I would be careful jumping and sort out the brushes first Since the Regulator already jumps it if I remember it correctly.
( Bricks at 5 o clock shorts connection until it starts charging )
?? Taking out the Brushes And plug in and out the regulator Measure at brown and green ..perhaps