Lincoln Electric SVM154-A Service Manual page 63

F-18
TEST PROCEDURE
1. Remove input power to the LN-10 unit.
2. Using the 5/16 in. nut driver, remove
the wire drive cover.
3. Locate the motor armature leads for the
motor to be tested (one black (-) lead
and one white (+) lead). Do not discon-
nect the leads. See Figure F.1.
4. Apply the correct input power (42 VAC)
to the LN-10. Activate the gun trigger.
With the motor running, check the
armature voltage at the black lead #541
(-) and white lead #539(+). The normal
voltage range is approximately 1 to 25
VDC depending on motor speed. When
the armature voltage is increased the
motor speed should also increase.
TROUBLESHOOTING AND REPAIR
WIRE DRIVE MOTOR TEST (continued)
FIGURE F.1 — WIRE DRIVE MOTOR TEST.
(+)WHITE
LEAD
(-)BLACK
LEAD
5. If the correct voltages are NOT present
at the armature motor leads, check the
associated leads and plugs for loose or
faulty connections. See the Wiring
Diagram. If the leads and connections
are OK, the control board may be
faulty.
6. If the correct voltages are present at
the motor armature leads and the motor
does not run and vary speed with
changes in armature voltage, the motor
or gear box may be faulty. See Wire
Drive Motor and Gear Box Removal
and Replacement.
7. Install the wire drive cover.
LN-10
F-18