LG LBC22520ST makes loud knocking noise

[mhartsig]

My LG refrigerator, model LBC22520ST has begun making a knocking noise at all hours of the day and night.  The ice maker has been removed, as we don't use it and needed the space, so it is not an ice maker noise.  The noise actually sounds as if it is coming from inside the fridge.  It seems to be functioning fine, both the refrigerator and freezer.  Ideas?

[Samurai Appliance Repair Man]

May be the evaporator fan tapping on ice as it spins. You'll need to disassemble the freezer and verify visually. If you see ice built up around the fan, then we'll need to test the defrost system and check the defrost drainage system. If you rule those out, then replace both the main control board and the evaporator fan.

Part number: EBR41531303

Part number: 4811JJ2002K

[mhartsig]

Many thanks for the advice. Love your site - nothing else like it out there.