Thanks so much for the huge amount of work you've put into this - mad jock as well.
It's late, and I'll re-read the post tomorrow. But I'm uncertain about the impedance and stray voltages that my speakers might offer to the system.
Both types work well with another computer.
Both have some sort of internal amplification, the bigger being mains powered, the smaller 4 X AA cells, I guess aimed at the laptop market.
The rear plugs are on the M-Board and covered in a tin box. I've examined the solder joints to the M-B very carefully.
The front plug's 'instructions' to the Realtec software seems to be totally back to front. It's hard to get behind the bezel to inspect the pluggery but I'll guess I'll have to. At least putting the ribbon cable back seemed to bring the Realtec Speakers section to life. For now, I've pulled the ribbon plug off again to stop the repeated triggering of the menu.
That really is a very odd fault, and I know curiosity will get the better of me and I'll have to delve. However, the crisis in aviation right now might severely limit my time...we are booked to come home fairly shortly, with talk of much longer extensions to the ban.
