gates of a plurality of silicon controlled rectifiers scrs 162 167 respectively 12 volts is delivered to terminal 80 from the loom 11 the warp bars 32 37 are thus electrified in parallel as described hereinabove between the terminal 80 and the second terminal 81 the circuitry of the present invention further provides a current delivered from a power source such as battery 153 the power source may be either a direct current source or an alternating current source 122 utilizing a rectifier not shown battery 153 is connected to a normally closed reset switch 150 that connects two contact points 157 and 158 the plurality of indicator lights are connected in parallel each indicator light is in turn connected in series with one of scrs 162 167 the circuits controlling each of lamps 112 117 are identical therefore the operation is described in connection with the circuit for activating lamp 112 initially when the loom is in operation no current flows through lamp 112 and contact 132 is isolated from contact 142 because no drop wire establishes a connection through the conductors of warp bar 32 when a drop wire 40 shorts the contacts of warp bar 32 contacts 230a and 230a 39 become closed completing the circuit between positive terminal 80 and gate resistor 172 this injects sufficient current into the gate terminal of scr 162 to cause the scr to fire in response to its cathode to anode voltage when the scr fires current flows through lamp 112 once scr 162 fires it will remain in a conducting state until the anode to cathode current falls below a relatively low value.