Repair help? Lecroy waverunner 6050

I have a project involving this lecroy waverunner 6050.


It is damaged. Yet i believe it is worth repairing to at least shape my skillsets. Any suggestions? Art?

Tag on top says ch 4 not working. Do the other chnls / features work?. Get the manuals - hopefully with schematics, etc. My guess is someone burned out that chnl by feeding it to high voltage signal. Do a search and don’t stop at just using google.