Thanks for your answer.
We got a T5120 server for lab purpose (end of support), but the ILOM password was not known.
At the moment nobody can tell me howto startup the ILOM software from the beginning with the initial password 'changeme'.
To reset a lost ILOM password on a T5120, you need to put a jumper to connect pins 1 and 2 of J6801 on the motherboard. The J6801 you want is near the very back, middle of the jumper card right next to where the middle PCIe card would go. I've had to do this several times.