I've tried the multiface with another PCI card with the same result.
So, the Multiface must be broken.
I've opened it to check if there are any mechanical damages, but I found nothing. All capacitators look also fine.
Image: http://i.imgur.com/j3FQ9gR.jpg
So I checked some voltages on the board with the power supply plugged in.
After the big capacitor I get the full 12V, on the transformer, too.
But most parts on the board get only around 1.2-1.6V. I don't think that's right. There are two voltage regulators on the power supply section, one for 5V and one for 12V. On the 5V one I get the full voltage on pin 1 and 2 but on the 12V one I get only on the second pin 12V, on the first one is nothing. When I bridge both all LEDs flashing.
I think this voltage regulator is broken but I'm not shure.
Cause I'm not able to repair it, I will probably sell it. I don't think to let repair such an old device from the support isn't an option.