Lincoln Electric Ranger 305D Service Manual page 116

F-62
CHOPPER MODULE FUNCTION TEST ( ontinued)
TEST PROCEDURE
1. Perform the
2. Make sure that there is nothing plugged into Procedure.
either of the Amphenol receptacles.
3. Place idle switch in the "HIGH" position.
4. Place the mode switch in the "CC-STICK"
position.
5. Place the Welding Terminal switch in the
"REMOTELY CONTROLLED" position.
6. Start the engine and allow it to stabilize at
high idle RPM.
7. Check for 80 to 100 VDC at terminals B1- to
B2+ and B4- to B5+ of the chopper module.
See wiring diagram and figure #1.
8. If the correct DC voltage is not present at ter-
minals B1- to B2+ and B4- to B5+, check for
damaged conductors or faulty connections
between the chopper module, the output rec-
tifier, and the stator weld winding. See Figure
F.17. See the wiring diagram. Perform the
Stator Voltage Tests, and the Output
Rectifier Test.
TROUBLESHOOTING & REPAIR
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FIGURE F.17 – POWER MODULE CONNECTIONS
HL W6
HL W4
HL W9
SL302
Case Cover Removal
RANGER 305D
B7
B8
B4
B1
B2
B5
B6
B3
SL13
SL301
SL14
9. If the correct voltage is present at terminals
B1- to B2+ and B4- to B5+ of the chopper
module, check for DC voltage at the chopper
module terminals B2+ to B3-, and B5+ to B6-
, If significant voltage is present, disconnect
leads #23 and #25 from the chopper module
PC board. If voltage is still present, the cop-
per module is shorted and should be
replaced.
10. If the voltage drops to 0 VDC after the #23
and #25 leads have been disconnected, the
control PC board is driving the chopper mod-
ule when it should not be doing so.
Reconnect the #23 and #25 leads and per-
form the Weld Control Board Gate Drive
Test.
11. Reconnect leads #23 and #25, and place the
Welding Terminal switch in the "WELD TER-
MINALS ON" position.
12. Check for about 58 VDC between Chopper
Module Terminals B2+ to B3-, and B5+ to B6
and between the welder output terminals.
See Figure F.17. See the wiring diagram.
HL W11
HL W5
HL W8
F-62