Late 2009 iMac 21.5" mini display problem

[Niklaasuk]

I have tried three different mini display to vga adaptors and cannot get the mac to detect the displays at the other end, (of which I have tried two)

The vga cable (tried also with two different ones) works, as have connected to a pc and no problem, plus the power buttons on the monitors show up blue when on and amber when asleep, the vga cable when attached stays blue, but the moment the adaptor is attached, the button(s) turn amber

I have PRAM reset & SMC reset, all to no avail

How can I check if the mini display is functioning, as all I can find in 'ABOUT THIS MAC', is Thunderbolt - No Hardware Found, which is what I would have expected, but nothing obvious regarding Mini Display

Any ideas please?

 

[Ubuntu]

What happens when you press Detect Displays in the Displays preferences?

 

[Niklaasuk]

Late 2009 iMac 21.5" mini display problem

Absolutely nothing

I have also attempted a firmware upgrade with the cables attached and the message 'No mini display to vga adapter found' shows up, I have tried this with the vga cable attached at both ends and wit the adapter only