The so called pin #4 of the BT card is the pin that was connected to C32 which in turn was connected to the internal mic(+). Double check it, starting from the internal mic(+) end, in order to identify correctly pin #4 of the BT card.
---------- Post added at 10:51 AM ---------- Previous post was at 10:48 AM ----------
I confirm Th mic signal from the socket has continuity to pin 4 on the BT card, which has continuity to the pad where the C32 resistor was but not to the other side which is cut.
Stumped here, was expecting this to be easy!
Is there a BT mic volume in software that needs to be enabled or set?