Lincoln Electric RANGER 305 D Service Manual page 66

RANGER 305D
Observe Safety Guidelines
detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
The machine welds, but it will not
maintain a steady output. The arc
may suddenly get hotter or colder.
(continued)
The weld output cannot be
adjusted with the front panel output
control knob in one or more weld
modes. The weld output terminals
have normal OCV (Open Circuit
Voltage), The AC auxiliary power is
normal and the engine operates
normally.
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely,
contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
WELD OUTPUT PROBLEMS
POSSIBLE AREAS OF
MISADJUSTMENT(S)
7. The weld cables may be
coiled, or wrapped around
metal reels or racks. This can
cause excessive electrical
inductance in the weld circuit.
Try welding after uncoiling the
cables, or disconnect the
existing weld cables and
attach a set of adequately
sized, short test cables.
1. Remote control devices
completely disable the front
panel control in all modes
except touch start TIG mode.
Make sure nothing is plugged
into either of the Amphenol
receptacles.
2. Check for dirt or moisture
contamination in either 6 pin or
the 14 pin amphenol receptacle.
C UTION
F 9
TROUBLESHOOTING & REPAIR
TROUBLESHOOTING GUIDE
RECOMMENDED
COURSE OF ACTION
6. The output control or arc
control potentiometers may be
defective or grounded. The
mode switch may also be
faulty. Perform the Control
Potentiometer and Mode
Switch Resistance Test.
7. The Amphenol receptacles
may be contaminated or
defective. Perform the
Remote Receptacle
Resistance Test.
8. Replace the weld control PC
board.
1. Perform the Remote
Receptacle Resistance Test.
2. The output control
potentiometer may be
defective.
3. Perform the Control
Potentiometer and Mode
Switch Resistance Test.