Many automation systems utilize the Measurement Computing Systems -8 USB converter box for cue closure inputs. The is an instrumentation interface with differential isolated inputs designed to handle up to 500Vac or dc. Its use for broadcast automation requires an external power supply, which means another wall-wart to clutter up the dc strip or a 9V battery to be replaced regularly. However, the unit has a 5V regulator on the circuit board, and with the addition of two tack-soldered leads this can be made to provide the voltage to operate the inputs. Simply lift open the cover, and solder wires to both ends of capacitor C2. Connect the positive lead of the capacitor to switch and bring it back to the A sides of the inputs. Then connect the negative lead from C2 to the B sides of the inputs. If desired, a small picofuse can be added to the positive lead to protect the power supply.
Landry is an audio maintenance engineer at CBS Radio/Westwood One, New York.
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