Troubleshooting; Electrical Diagram - MAC TOOLS MW250 Owner's Manual

No weld
output;
wire does not feed; fan
-s
motor continues to
run
and pilot light is
off.
No weld
output;
wire feeds.
-~
Connect work clamp
to get
good metal to metal contact.
Replace contact
tip.
Section
-s
3-6
-s
5-2
-s
3-6
-s
3-5
-s
5-2
Figure
4-3
1-~
5-4
SECTION
6-
ELECTRICAL DIAGRAM
5-5.
Troubleshooting
I
Welding Trouble
INO
weld
output;
wire does not feed
READ SAFETY BLOCKS at start
of
Section 5 before proceeding.
Remedy
Secure power cord plug in receptacle.
Reset circuit breaker CB1. Replace
fuse Fl and/or F2.
Replace building
line fuse
or
reset circuit
breaker if open
Secure gun trigger plug in receptacle
or
repair
leads,
or
replace
trigger
switch.
Thermostat open (overheating). Allow fan to
run;
the thermostat
will close when the unit has cooled.
Electrode wire feeding stops during
-s
welding.
I
Low weld
output
-
Connect unit
to
proper
input voltage
or
check for low line
voltage.
~ -
3-6
]
Wire Drive/Gun Trouble
_________
-s
5-4
Straighten
gun
cable and/or replace damaged
parts.
Adjust hub tension.
Adjust drive roll pressure.
Replace contact tip
if blocked.
Clean
or
replace wire inlet guide
or
liner if
dirty
or
plugged.
Replace drive roll
or pressure
bearing
if
wom or
slipping
Secure gun trigger plug in receptacle
or
repair leads,
or
replace
trigger
switch.
Check and replace Fl and/or F2.
Check and clear any restrictions
at
drive assembly and liner
Have nearest Factory
Authorized Service Station check drive
motor.
--a
--s
--s
--s
--s
--a
--a
--a
--a
3-7
3-8
5-4
5-3, 5-4
5-3
3-5
5-2
5-3, 5-4
WI
5Z
r~
~u~i
AAA-A-A
~ ;~~ ci
c
ci~
~3~<1FU~
R3-1I~>---~-<3
14.
~ 4
~3-2
>>~<
I
~3-9
~3-~
>~~~~<n
Figure 6-1. Circuit
Diagram
For Welding Power Source
I~4TNE
SB-174 099-A
OM-154 501
Page 17