Abstract: In a system for troubleshooting a unit containing microprocessor-based digital circuitry including a bus, wherein the system includes a digital test apparatus that emulates the microprocessor of the unit to test components on the bus and a device for interfacing signals between the test apparatus and the microprocessor comprises a clip that mounts to the microprocessor in electrical contact with the microprocessor leads. The clip preferably is of a type adapted to attach resiliently to the leads of all four sides of a soldered-in microprocessor in a leaded chip carrier housing. A connector to couple the clip to the test apparatus through a wire harness is mounted on a printed circuit board carrying pins corresponding to the lines of the microprocessor bus and the clip, and cables extending from the circuit board to the clip are coupled to the pins of the circuit board and clip by push connectors.