Hey, made an account just to say this. LPC4320FBD144 is a microprocessor and LPC1820FBD144 is a microcontroller. These likely have proprietary firmware flashed to them, and as such, would be impossible to replace.
You would have to flash the firmware to new ICs, and then solder them to the board. It's very unlikely you'll find firmware files for those two specific chips anywhere, as PreSonus probably hasn't released that.
There's a very small chance your repair man was wrong about the damaged components, and it may be possible to fix it if that's the case, but this is very unlikely. Maybe open it up yourself (with it unplugged, of course) and see if anything is visibly burnt or damaged-looking?
