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PROBE BRAKE OPERATION
The MicroChine's Probe Brake feature instantly stops all rotary machining at a selected layer depth for
nondestructive multilayer repair.
In use, the Probe Brake cable is attached to the PROBE BRAKE Receptacle on the front panel of the
system power source. The opposite end of the Probe Brake cable must be connected to a connector pin,
component lead, or a soldered-on extension of the circuit board assembly. The connection point must
have electrical continuity with the internal conductor to be repaired. A schematic diagram or layout
artwork of the printed wiring assembly (PWA) is a great aid in locating the most effective connection point
for the Probe Brake cable. The electronic Probe Brake circuit stops the MicroChine instantly when the
working drill or mill makes contact with the internal layer of circuitry, in continuity with the Probe Brake
lead, and the Status LED illuminates Red in color. Once the brake circuit has stopped the motor, the
finger switch or foot pedal must be released before the motor can be started again.
WORKPIECE GROUNDING
The Probe Brake may activate prematurely if the workpiece is attached directly to ground. The Probe
Brake circuit operates when a connection is made between the MicroChine bit and the conductor to which
the Probe Brake Lead clip is attached; a low current flows through this connection to activate the Probe
Brake. Low resistance to ground or high capacitance in the workpiece circuit connected to the Probe
Brake lead may activate the electronic sensing circuitry, in continuity with the Probe Brake lead, in the
system power source. In this case, PACE recommends the use of the PROBE BRAKE Receptacle to
ground the workpiece. To prevent electrostatic build-up, this receptacle provides an impedance of 1,000
ohms to ground.
Figure 118. Workpiece Grounding
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