-snip-
First thing, check the USB connector it might have full of dirt and rust to remove them use a brush and lacquer thinner(Or any rust cleaner, alcohol, or fluid) then test it again.
If not, you must disassemble the Trezor as shown in the image above then do this clean the ICs with brush and thinner make sure LCD is far and protected.
If it still doesn't work it might have some shorted capacitor or maybe one of the IC pins has lost contact with the board so you might need to resolder the pins to fix the issue.
Most people can probably still do the first and second tips. But for the third tip, special skills are needed, including knowing which part is the source of the problem, is it enough to re-solder it, or even have to replace the damaged spare part.