The MF units handles that function via the apple. Check all the wires for chaffing (especially the TBU) and make sure the apple is secure in the base. That is why the have a metal locking system. Does it display hits on the apple but not record them as damage on the MF unit? One of the safeguards in the TBS is that it cannot give or record hits w/o the apple. If the apple is lights when hit and the wires and connections & wires (Comm cable too) are all good and you have good charged batteries (Helpfull Hint: Low batteries cause the majority of all tank electronic issues) then the MF is the likely culprit. I know you have several Tamiya tanks Troy. Try swapping apples and then swap in another MF. The MF unit numbers do not matter for this purpose. To further isolate the problem is you can also put the suspect units in a good tank to see if the problem in just in one component or more. Call me tonight if you like. I am finishing a Tiger and M26 for customers and will be up late.