Tweco 251 Thermal Arc Fabricator - Manual (Page 63)

FABRICATOR 251
Manual No. 0-4847 5-7 SERVICE
5.05 Power Supply Problems
FAULT CAUSE REMEDY
A. Indicator light is ON but welding
arc can not be established.
1. Power On/Standby switch
in standby position.
a. Switch the power On/Standby
switch to the “On” position .
1. Primary fuse is blown. a. Replace primary fuse. B. Mains supply voltage is ON.
Indicator light is not lit and
welding arc can not be
established. 2. Broken connection in
primary circuit.
a. Have an Accredited Thermal Arc
Service Agent check primary
circuit.
C. Mains indicator light is not lit
but welding arc can be
established.
1. Indicator light is open
circuit.
a. Have an Accredited Thermal Arc
Service Agent replace Indicator
light.
D. Mains supply voltage is ON and
Indicator light is lit but when the
gun trigger switch is depressed
nothing happens.
1. Gun trigger switch leads
are disconnected.
a. Reconnect.
1. Electrode wire stuck in
conduit liner or contact tip
(burn-back jam).
a. Check for clogged / kinked MIG
Gun conduit or worn contract
tip. Replace faulty
component(s).
E. Mains supply voltage is ON, no
wire feed but gas flows from the
MIG Gun when the gun trigger
switch is depressed.
2. Faulty control PCB or
Tweco Gun
a. Have an Accredited Thermal Arc
Service Agent investigate the
fault.
F. Wire feeds when the gun trigger
switch is depressed but arc can
not be established.
1. Poor or no work lead
connection.
a. Clean work clamp area and
ensure good electrical contact.
G. Wire continues to feed when the
gun trigger switch is released.
1. The Weld Mode Switch has
been set to 4T (latch
operation).
a. Set the Weld Mode Switch to 2T
(normal operation).
1. Worn or dirty contact tip a. Replace
2. Worn feed roll a. Replace
3. Excessive back tension
from wire reel hub roll.
a. Reduce brake tension on spool
hub
4. Worn, kinked or dirty
conduit liner
a. Clean or replace conduit liner
H. Jerky wire feed
5. Low Swing Arm pressure a. Increase the Swing Arm
pressure.
1. Gas hose is cut or pinched a. Check hose and replace or
repair.
2. Gas passage contains
impurities
a. Disconnect gas hose from the
rear of Fabricator then raise gas
pressure and blow out the
impurities.
3. Gas regulator turned off a. Turn on.
I. No gas flow
4. Gas cylinder is empty a. Check cylinder volume and
replace or refill as needed.
J. Gas flow continues after the gun
trigger switch has been
released.
1. Gas valve has jammed
open due to impurities in
the gas or the gas line.
a. Have an Accredited Thermal Arc
Service Agent repair or replace
gas valve.
Table 5-4: Power Supply Problems