V50 II electrical issue

After a lengthy three month refurb on my newly aquired V50 II I finally started her up a couple of days ago and everything appears to be fine apart from a charging issue which has got me a bit stumped. I am sure the generator was working fine when I bought the bike.
During the refurb I removed the loom for various repairs and also replaced the mechanical voltage regulator with a solid state VR from Gutsibits.
Of course there was a possibility that the new VR was at fault so I have tried the old one but no joy.

With the violet wire connected to DF there is no output from any of the phases but if I connect a slave 12 volt battery to DF I get about 17 volts AC at 5000 rpm from each of the phases which tends to indicate that the alternator is ok.
Oddly there is a 10.5 volts DC signal on the violet wire.
The battery is fine and fully charged.

Any thoughts from Guzzi electrical gurus would be appreciated.

I assume this has the standard Bosch system. It’s usually a dodgy connection somewhere.
There are a couple of good fault finding guides here…

Gutibits The Shed. https://www.gutsibits.co.uk/pr/TheShed/techdocs.php

Or Charging around the circuit