TM600 DISEqC switching failure?

My TM600 runs a motor dish via a DISEqC switch Port 1 and a larger dish for SKY UK on the DISEqC switch Port 2. This is a 'custom' satellite configuration in the STB with Astra 2 (SKY) LNB setting as '1' and all other satellites set to '0'.

This has always worked well, but now it won't switch ports and just remains on Port 1 . I've changed the DISEqC switch and tested it with another STB and it definitely working. I've done a Factory Reset on the TM600 and reloaded everything, but still the same.

As far as I can work out, the STB is not commanding the DISEqC switch. The rotor works fine on Port 1. The SKY dish works fine when plugged into Port 1 too (irrespective of the DISEqC settings in the box). So it's only using Port 1 of the switch (which is open by default).

Has anyone experienced an issue like this? Is the DISEqC switching part of the firmware, or is it built into the box? Could it be kaput?

Any advise much appreciated.

I've now spent a few hours bench testing my TM600.
With a simple two satellite DISEqC configuration the switching works fine.
But when I use a DISEqC motor configuration (set as LNB 0) with a second LNB (from a seperate dish set as LNB 1) it will not switch, but remains on Port 1.
I've used this setup for several years and until now it has worked well.
I guessed firmware controls the DISEqC switching, so I installed an older firmware version, but still no change.

Any ideas?

Finally sorted. All my fault. Lost count of the number of times I went though this set-up, but I finally found another menu level for the second LNB.