Lincoln Electric COMMANDER 400 SVM133-B Service Manual page 116

F-62
TEST PROCEDURE
NOTE: In this test procedure, the positive output
stud is used for common.
1. Using the 5/16" nut driver, open the control panel
and tilt out. Remove the control board cover.
Start the machine.
WARNING
There are high voltages present
inside the control box while the
machine is running. THE VOLTAGES
ARE HIGH ENOUGH TO KILL.
extreme caution to avoid the back-
side of the receptacles, breakers, and
terminal strip while checking voltages inside the
control box.
TROUBLESHOOTING AND REPAIR
SHUNT CALIBRATION TEST (continued)
Use
Figure F.29 Control Board Plug J1
C112
J2
J6 J5
Plug J1
+Pin #3
COMMANDER 400
2. Set the range switch to the CC/General fabrica-
tion tap. Using the fine control pot, set the pre-
set amps on the display to 300 amps.
3. Using a grid bank, load the machine to 300 amps
at 25 volts using an external ammeter and volt-
meter.
4. At the control board, measure the voltage from
J1 pin 3 (pos. lead) to J1 pin 2 (neg. lead). See
Figure F.29. The voltage should be 25 mVDC +/-
5%. The current reading on the display should
be within +/- 5% with the external ammeter. See
Figure F.29.
5. If step 4 fails, the shunt is out of calibration and
must be replaced.
6. If the test is complete, replace the control board
cover and close the control panel.
J20
J22
J1
J8 J7
J4
-Pin #2
F-62