Sonoma installed but second monitor no longer works

Hi there,

I have just upgraded to Sonoma on my Optiplex 3050.

Everything seems to be working great and it was working until I followed the steps to reenable broadcom wifi. Since then my second display shows no signal. System information shows the monitor and the correct resolution and the mouse even moves over to it but alas no picture.

Any idea on where I should start?

Many thanks.