If you have a comparator wich would lock a repeter (see the "1.jpg"), and then you light up the comparator, the repeter should be locked but it does not load the model for it (see the "2.jpg").
It is locked bec you can't light up the repeter or if it was, you can't switch off the repeter.

The only way i found to make the repeter load the model is to right click on the comparator.