Lincoln Electric RED-D-ARC DX450 Service Manual page 62

F-18
Observe Safety Guidelines detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
The engine will not develop full
power.
The engine will not idle down to
low RPM. The machine has nor-
mal weld and auxiliary output.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely,
contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed.
Call 1-888-935-3877.
TROUBLESHOOTING AND REPAIR
POSSIBLE AREAS OF
MISADJUSTMENT(S)
FUNCTION PROBLEMS
The fuel may be old or contaminat-
ed. Supply the engine with clean
fresh fuel.
The fuel filter may be clogged,
replace if necessary.
The air filter may be clogged,
replace if necessary.
Make sure the idle switch is in the
"AUTO IDLE" position. Make sure
there is no external load on the
weld terminals or the auxiliary
power receptacles.
CAUTION
The engine may be in need of
adjustment or repair.
Put the idler switch in the "Auto"
position. Make sure there is no
external load on the weld terminals
or the auxiliary power receptacles.
Check the voltage from lead #405
(Plug J2 pin 5) on the control
board to lead #5G (Plug J2 pin 3).
Normal is 0 volts DC. This is the
low idle signal from the Weld con-
trol Board to the Engine Control
Unit. Also check the continuity
from lead #405 to lead #31GV a
the Engine Control Unit. If the cor-
rect voltage is read and the engine
will not go to low idle RPM, the
Engine Control Unit may be faulty.
If a voltage greater than 0 Volt DC
is read and the idler switch is func-
tioning correctly, the Weld Control
Board may be faulty. Also check
leads #257 and #256 at the idler
switch. Make sure they have con-
tinuity to the Weld Control Board.
See Wiring Diagram.
DX450
F-18
RECOMMENDED
COURSE OF ACTION