Lincoln Electric LN-742 LN-742 Operator's Manual page 38

E-5
PROBLEMS
(SYMPTOMS)
The purge key does not activate
the gas solenoid. The solenoid
does activate when the gun trigger
is pulled.
The gas solenoid does not activate
either when the purge key is
pressed or when the gun trigger is
pulled.
The cold inch key does not activate
the wire feed motor. The wire feed
motor operates normally when the
gun trigger is pulled.
The HI symbol appears on the dis-
play when the voltmeter function is
selected.
The Er symbol appears on the dis-
play.
The EXX appears on the display.
(XX is some number from 1 to 10.)
The EP symbol appears on the
display.
The uP symbol appears on the dis-
play. (Microprocessor RAM error.)
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your
Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
TROUBLESHOOTING
Observe all Safety Guidelines detailed throughout this manual
POSSIBLE
1. Contact your local Lincoln
Authorized
Facility.
1. Check plug J6, located on the
control board for loose or faulty
connections.
1. Contact your local Lincoln
Authorized
Facility.
1. If the arc voltage is greater than
44 VDC, this is a normal condi-
tion. The voltmeter only reads
0-44 VDC.
1. This is an EPROM error. The
parameter recalled at power-up
is out of range. Press any key
to reset unit. Check all weld
settings before proceeding with
weld.
1. Remove input power to the
feeder (42 VAC). Wait 5 sec-
onds. The symbol should not
reappear
returned.
1. Remove input power to the
feeder (42 VAC). Wait 5 sec-
onds. The symbol should not
reappear
returned.
1. Remove input power to the
feeder (42 VAC). Wait 5 sec-
onds. The symbol should not
reappear
returned.
LN-742 & LN-742H
CAUSE
Field Service
Field Service
If all recommended possible areas of
misadjustment have been checked
and the problem persists, Contact
your local Lincoln Authorized
Field Service Facility.
when power is
when power is
when power is
CAUTION
RECOMMENDED
COURSE OF ACTION
E-5