is it possible to repair a DMM which was burned by putting the leads into 230V on a frequency-measuring setting?
Small parts like transistors don't stop the 230V. It's very probable that most of the 230V went into the controller and that that is fried as well. This would explain why the meter doesn't do nothing anymore. Having the controller replaced may cost you more than a new DMM (if they replace it at all, you'll probably get a replacement DMM). This is a custom IC which you won't find to do it yourself.
It's impossible to identify the fried parts without a schematic if they don't have readable markings anymore. (It's even impossible to identify good parts without marking with absolute certainty.)
TP1 and TP2 probably refer to test points rather than components; TP is normally not used as a prefix for components.