Replace the headphone port on the logic board?

Yes we are replacing the whole part it is much easier than faffing about trying this and that as nothing was changing, no settings available zero. If the issue still persists then we will try this https://www.youtube.com/watch?v=OdrNUOEy...

@livfe - If replacing the jack with the correct one (there are different jacks! Between the headphone and the auxiliary and the headphone are different. There are two different headphones as well between an analog only and a dual analog/digital (Red LED inside) so make sure you used the correct one.

So while shorting out the switch should allow the speakers to work you’ll discover the speakers won’t turn off when you plug in a headphone and as there are two switches one for the left and a different one for the right you won’t have both speakers working as well!

So if you do this leave the jack off so there is no confusion do seal the hole so nothing sneaks in.

@danj The jack is from an identical board same year and model so there shouldn't be any issues.... it is in the shop for repair so I will get them to double xheck that the part is the same, they will also have a look to see if the switch inside is stuck as maybe I missed that.

@danj Our friend Michael Scope revealed a missing resistor on the board by the headphone part.... did a transplant from the donor board and solved it now is OK.

@livfe - Good inspection is key! If your good let’s close this out.