T400 no SPDIF via Minidock 2504

[annalogg1]

Can't get any output from the SPDIF connector on the RH side on my 2504 dock.

My T400 has Conexant 20561 shown as working with sound output set to SPDIF. On testing the graphical representation shows "sound" but there's nothing reaching my external DAC which I know is working with a known good co-ax connector.

Have tried unistalling and reinstalling the 20561.

Latest driver (4.92.12.0) installed though I have tried reverting to 4.92.10.0 and that does not get it working either.

Any ideas Thinkpad People?