81100 Family: Self test fails

The unit is not defective, this behavior is a result of the extensive self tests:

During the self tests the external inputs and the levels at all outputs are tested.

If a signal is applied to an external input this can cause a self test failure as the variation of the threshold values at the inputs may not have the expected result. If a load different from 50 ohm is connected to the trigger or strobe output, the expected levels cannot be achieved during the output level test.