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BOSS Inverter Mig 250 Operating Manual
7.04 Power Supply Problems
Fault
Cause
Remedy
1. Input power supply
voltage is ON. Indicator
light is not lit and welding
arc can not be
established.
A Primary fuse is blown.
B Broken connection in primary
circuit.
A Replace Primary fuse.
B Have an accredited BOSS service
agent check primary circuit.
2. Input power indicator
light is not lit and welding
arc can
not be
established.
Indicator light is open circuit.
Have an accredited BOSS service agent
replace indicator light.
3. Input power supply is ON
and indicator light is lit
but when the gun trigger
switch is depressed
nothing happens.
Gun trigger switch leads are
disconnected.
Reconnect.
4. Input power supply
voltage is ON, no wire
feed but gas flows from
the MIG gun when the
gun trigger switch is
depressed.
A Electrode wire stuck in conduit
liner or contact up (burn-back
jam).
B Faulty control PCB.
A Check for clogged/ kinked MIG gun
conduit or worn contact tip, replace
faulty components.
B Have an accredited BOSS service
agent investigate the faulty.
5. Wire feeds when the gun
trigger switch is
depressed but arc can
not be established.
Poor or no work lead connection.
Clean work clamp area and ensure good
electrical contact.
6. Wire continues to feed
when the gun trigger
switch is released.
The mode selector switch has
been set to 4T (latch operation).
Set the mode selector switch to 2T
(normal operation).
7. Jerky wire feed.
A Worn or dirty contact tip.
B Worn feed roll.
C Excessive back tension from
wire reel hub.
D Worn, kinked or dirty conduit
liner.
A Replace.
B Replace.
C Reduce brake tension on spool hub.
D Clean or replace conduit liner.
8. No gas flow.
A Gas hose is cut.
B Gas passage contains
impurities.
C Gas regulator turned off.
A Replace or repair.
B Disconnect gas hose from the rear
of Inverter Mig 250 or then raise gas
pressure and blow out the
impurities.
C Turn on the gas regulator.
9. Gas flow continues after
the gun trigger switch
has been released.
Gas valve has jammed open due
to impurities in the gas or gas line.
Have an accredited BOSS service agent
repair or replace gas valve.
Table 10
