In a DIY forum, someone made the suggestion to remove the electronics from KH120 with electronics defect and instead install a passive crossover as in the Klein + Hummel P110, which is probably very similarly equipped. (picture of the KH P110 is taken from the web)
Add a cheap Class D amp and you have a second life for the KH 120. Repair at the manufacturer is apparently not worth it.
Funny idea, for hobbyists I think. Unfortunately, I have the circuit diagram of this crossover nowhere found. Does anyone of you know a source? If I had broken KH120, I would try it.
You could of course also use an active crossover and 4 amplifier channels, but the effort should be small, so that it pays off.