Troubleshooting Guide, Testing The Gun

Troubleshooting Guide

Regardless of which gun or feeder used, all MK Products’ push-pull guns operate on the same principle. The slave motor in the feeder runs at a fast, constant speed, but has very low torque. It is always trying to feed more wire than the gun motor wants, and when the motor gets all it wants, it slows the slave motor, preventing a bird’s nest. Because of the low torque produced by the slave motor, a brake system is used to prevent wire overrun rather than tension. The drag adjustment in the feeder is used simply to keep the wire slightly taut, so it will not pull off the spool while feeding wire.

The high torque 24VDC gun motor is controlled by a solid state speed control located in the feeder, and a pot located in the gun. The gun motor, potentiometer, and micro switch are connected to the cabinet/control box via a control cable and amphenol connector. If this cable becomes damaged, a variety of symptoms can occur, depending on which wire(s) break. To test, check each wire for continuity and shorts.

Remember, the micro switch in the gun activates both the slave motor and gun motor circuits in the cabinet. Therefore, if the slave motor and brake solenoid operate, but the gun does not, look more toward the gun motor’s 24V circuits, speed control, control cable, or the gun motor. If nothing operates, look more toward the slave motor’s input, micro switch leads, or micro switch.

Testing The Gun

Reference the "W" clocked gun wiring diagram on

the CobraMAX™ electrical diagram (in appendix) for information

about pin-outs and locations.

Motor Check

Remove the gun connector from the cabinet.

Using the gun amphenol connector, check the resistance across pins “A” and “B” (motor leads). The resistance across the motor should be between 5 - 10 ohms as the potentiometer is turned.

If an open circuit or short exist, check the motor leads and motor independently.

Testing the Potentiometer - “W” Clocked

Using the gun amphenol connector, check the resistance across pin “D” (wiper) and pin “C”. The resistance should vary from 0 - 5K ohms as the potentiometer is turned.

Check the resistance across pin “D” (wiper) and pin “G”. The resistance should vary from 5K - 0 ohms as the potentiometer is turned.

Testing the Micro Switch

Using the gun amphenol connector, check for continuity across pins “E” and “F” when the trigger is pressed.

CobraMAX™ Owner's Manual - Page

IM774 specifications

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