It is very likely that you are using the uncoded receiver only unit in combination with a coded complete unit. To confirm this just check the package of the receiver only unit for "CAUTION, THIS RECEIVER IS NOT COMPATIBLE WITH THE FLIPPER/DELFY MODEL" and that the complete unit package or even the actual appliance has the Delfy logo. The same problem will arise if you attempt to combine an uncoded complete FLIPPER with a coded receiver only FLIPPER.