Hi all,
Quick check of the FET's learned this:
the recommended IRF730 has a input capacity of 620pF
The ordered replacement IPA60R280E6 has a typical input capacity of 950pF.
Time will tell if the transistor driving the FET is able to drive this larger capacity.
For what it's worth: the broken FET I found in my scope when I got is was a IRF710 (400V 200pF...)
To be continued,
Un saludo,
Leo