Trouble Shooting Chart - Snap-On MM140SL Owner's Manual

The Trouble Shooting Chart is a guide in identifying and correcting
possible troubles which may occur when operating this equipment.
FAULT
No main power,
fan does not
operate,
"on" indicator
light is off.
Main power on,
torch
trigger
activated,
no response.
Main power on,
torch
trigger
activated,
no wire feed
but contactor
operates &
gas flows.
- USE THIS IDENTIFIER, ALONG WITH THE SCHEMATIC DIAGRAM FOUND IN THE SERVICE
(SYMBOL*)
MANUAL, FOR TROUBLE-SHOOTING PURPOSES.
TROUBLE SHOOTING
FOR TECH. SERVICE, CALL TOLL-FREE 1-800-232-9353
POSSIBLE CAUSE
EQUIPMENT MALFUNCTION
MM140SL switch is "OFF".
Wall breaker is "tripped".
"Open" circuit breaker
on MM140SL.
Loose or broken connection
in power input circuit.
MIG torch unplugged.
Faulty trigger switch.
Fault in torch cable.
Loose or broken connection
on wiring harness.
Wire feed motor unplugged.
(RC5)
Faulty control transformer.
(T2)
Loose spot timer circuit
board.
(PC2)
Defective spot timer
circuit board.
Pressure roll arm unlatched. Latch arm & add tension.
"Slippage" at drive rolls.
Wire path restricted.
5 amp mini breaker is
tripped.
(CB2)
Wire feed circuit board
needs calibrated.
Defective wire feed
circuit board.
Faulty wire feed motor
or connection.
Faulty motor relay.
Loose or broken connection.
(continued on following page)
Snap-on Tools Corporation Kenosha, WI 53141-1410
(SYMBOL*)
(CB1)
(CB1)
(S1)
(PLG2)
(CR2)(PC2)
(PC1)
(M)
(CR1)
REMEDY
Turn switch "on".
Reset wall breaker.
Reset or replace
breaker.
Tighten or repair
connection.
Plug in MIG torch.
Replace micro switch.
Check torch cable
for continuity.
Check or repair
connections.
Plug in motor.
Check for 28VAC output.
Install properly.
Replace board.
Increase drive roll
tension. See page 8.
Clean path or replace
torch liner.
Reset or replace
breaker.
Calibrate wire feed
circuit board. See
page 19.
Replace circuit board.
Repair or replace
faulty item.
Check motor on a
12VDC battery.
Sand points or replace
relay.
Tighten or repair
connection.
15