If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
216-383-2531 or 1-800-833-9353.

PROBLEMS
(SYMPTOMS)

POSSIBLE AREAS OF
MISADJUSTMENT(S)

RECOMMENDED
COURSE OF ACTION

FUNCTION PROBLEMS

The SET voltage is erratic or not
adjustable over the entire range of
control. The actual voltage is also
erratic like the SET voltage.

1. Check for loose or faulty con-

nections on leads #634, #635
and #636 between the voltage
control potentiometer (R3) and
the voltage PC board.

1. Remove power to the LN-9 and

disconnect Plug J1 from the
voltage PC board. Check the
resistance of the voltage control
potentiometer (R3). When
measured from the wiper (lead
#635) to lead #634, the resis-
tance should vary smoothly
from 0 to 10,000 ohms when the
shaft is rotated.

2. The voltage PC board may be

faulty. Replace.

The field fuse (F101), located on
the power PC board, repeatedly
fails.

1. Very rapid and repetitive gun

triggering can possibly cause
the field fuse to fail.

1. Perform the

2. Perform the

3. Disconnect the meter board. If