Lincoln Electric SAM400 - Manual (Page 31)

E-8 TROUBLESHOOTING E-8
GROUND TESTS
This machine is equipped with solid-state electronic
components which can be damaged if subjected to a
ground test or a megger test without observing special
precautions as outlined here:
A. Prior to the ground test always turn the engine off
and remove the two Printed Circuit boards mounted
on the rear of the welder control panel. For access
remove the welder roof and the metal enclosures
over the PC boards. Remove one screw from the
smaller board and two screws from the larger board
and pull each board straight out from the connector
block. There are no wires to disconnect.
B. Connect the following jumpers:
1. Welding generator frame to base.
2. Across D13 (#232 to #1)
3. Across D14 (#234 to #75).
C. Place jumpers across the following points, see
wiring diagram.
1. Across the voltmeter terminals if the unit is
so equipped.
2. Positive side of SCR bridge (#75) to #214
on the SCR bridge located on the rear
panel of the control box.
3. Positive side of SCR bridge (#75) to #212
on the SCR bridge.
4. Across C5 on the SCR bridge.
5. Negative side of the SCR bridge (brown
generator field lead) to #214 on the SCR
bridge.
6. Negative side of the SCR bridge to #212 on
the SCR bridge.
7. Across C6 on the SCR bridge.
8. #1 on the two diode aluminum finned heat
sink to #212 on the SCR bridge.
9. #1 on the two diode aluminum finned heat
sink to #213 on the SCR bridge.
10. #2 on the base of D4, single diode mount-
ed on copper heat sink to #75 on SCR
bridge.
11. Across each of the three-phase bridge
diodes, jumper from the heat sink across
the diode on all six diodes.
NOTE: All jumpers must be as short as possible
SAM400 & 650
CAUTION