Question:
Does anybody have a schematic for wiring a Gamewell Box to run off household current. I have one I want to wire up and plug in, in my home office but everytime I plug in BANG there goes another fuse.

Answer: What you need is a DC power supply. The design voltage for street fire alarm boxes is forty eight volts but any DC power supply between twelve and forty eight should work. If you wire a bell or a relay in series with the transmitter (i.e. the firebox) and the power supply the whole thing will work. Keep in mind that telegraphic fire alarm circuits are series circuits. When the transmitter is idle and the door is closed the box is a dead short. Its mechanism is just part of the circuit conductor when it is not operating. If you place an appropriate relay or bell in series with the box then the circuit will work. What happens is that the current flows constantly through the coil of the relay or bell. The coil serves as the load on the power supply so that it's output is not shorted and it's fuse does not blow. To be suitable for the use the bell has to be a special type designed to sound on loss of power. Such bells are difficult to come by. It will be easier to use a relay to energize a regular bell. If you connect the bell to the relays normally closed contacts; These are the contacts that are closed when the relay is de-energized; the bell will sound when the circuit through the fire box opens. When you trip the box it's spring driven mechanism opens the line through the box a fixed number of times. This number is the fire box address. The one I have is numbered 1314. It's code wheel has one tooth a space, then three teeth and a space, then one , then four. Each time the wheel revolves it opens the circuit once for each tooth on the code wheel. Each time the circuit opens the bell sounds. The bell thus sounds out the boxes number. You can ask at any electronic hobby shop for a power supply that will run off house current and provide, say, twelve volts. You also need a twelve volt relay and a twelve volt bell. If you have further questions just ask. One word of warning. In many places it is unlawful to mount the fire box in any location accessible OR VISIBLE to the public unless it is clearly labeled OUT OF SERVICE. Even with labeling it would not be lawful in some localities.