MK Products COBRAMIG 300, Owner'S Manual, Page: 24 / 36

CobraMig
® 300
Owner's Manual -
Page 18
Troubleshooting Guide
Wire feeds but wire is not energized. Loose cable connection or no work
ground.
Check all power and ground
connections.
TRIAC in power supply defective. 1. Use volt meter to measure the
output voltage at the (+) and (-)
terminals on the back of the power
supply. Press gun trigger;
- If voltage is uncontrolled and
maxed out, replace the TRIAC.
- If no output is measured,
proceed to next step.
2. Remove Power Source side panel.
Use Volt meter to measure voltage
across (+) and (-) of TRIAC
terminals. Trigger and verify;
- If voltage does not change
when triggered then replace
Front PCB.
- If voltage does change
when triggered then replace
TRIAC
Front PCB defective.
Symptom Cause Remedy
Gas leaks from power block
connection.
Gun power pin connector not inserted
fully or defective o-rings.
Make sure the o-rings on the power
pin are good and that it is fully inserted
into the power block. Then locked in
place by turning knob.
Wire feeder does not lock into place
on top of power supply.
Bent mounting and or lock tabs. Adjust tabs as needed to align with
mount holes and locking mechanism.
System black out. No input line voltage. Check input voltage supply and fuse.
Unit not set internally to correct input
voltage.
Make sure your input voltage matches
what is specified on the voltage input
tag on your unit. See page 9 for
instructions on how to change input
voltage of your unit is necessary.
Bad F2 fuse (28VAC) on main board
P/N 003-2613.
If power supply fan is running then
check F2 fuse (28VAC) on main
board, replace if needed.
Unit does not respond to gun trigger. Gun trigger is defective. Press gun trigger to verify voltage
displays two step dash lines. If not,
unplug gun control cable. Use jumper
to jump connection pin 5 to pin 6.
- If voltage displays two step dash
lines while jumped then the gun,
trigger or cable is bad (see gun
manual). Replace if needed.
- If not, replace Front panel PCB
Front panel board is defective.
Brake solenoid or slave-motor not
working.
Main PCB is defective. 1. Press torch trigger, visual check that
relay on main PCB is energized.
- If yes, check F1, F3 fuses. Replace
as needed.
- If not, replace main PCB.
2. If fuses are okay and relay is
energized then use ohmmeter to verify
resistance per below:
Slave motor:
Red – Blue: approx. 180 Ohm
Black – White: approx. 180 Ohm
Brake solenoid: approx. 290 Ohm
Replace as needed.
F1, F2 input fuses on main PCB are
blown.
Brake solenoid or Slave motor
defective.
Wire feeds one speed only. Front PCB is defective. Set select button to wire feed display.
Use Volt meter to measure voltage at
J1-1 (GND) and J1-6 (POT) on Main
PCB.
Trigger and verify voltage changes
when adjusting the voltage knob or
buttons on the gun.
- If no change is seen, replace Front
PCB
- If it changes, replace Main PCB
Main PCB is defective.
Defective electrical cable.
Defectiive potentiometer (analog guns
only).
Defective control buttons (digital guns
only).
Check with meter, replace as needed.