It sounds like you might have a prepay unit where a coin deposit is required before the phone's network is cut through. Do you know what model the phone is? It should be stamped in orange paint on the back side. I know for sure that a 1D2 model will function fully without modification or the need for a coin deposit.

Also, check to make sure that there's nothing held in the escrow chamber by gently pushing in on the coin relay's armature to open the hopper and dump any coins that might be in there. When the coin relay fires, the contacts will mute out the phone's network so that the user doesn't hear the noise caused by the 130VDC sent to activate the relay.

Ed Vaughn, MBSWWYPBX