Lincoln Electric RANGER 305G EFI Service Manual page 52

LINCOLN ELECTRIC
13. Connect leads 23 (B7) and 25 (B8) and place the welding terminal switch in the "WELD TERMINALS
ON" position.
14. 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.13. See the Wiring Diagram.
15. If about 58 VDC is present at chopper module terminals B2+ to B3- and B5+ to B6-, but not at the
output terminals, there is a problem between the chopper module and one of the output terminals.
Check for damaged conductors or faulty connections on leads W7, W8, W9 and W10. Also check
the shunt, the choke and the connections at the back of the output terminals. See Wiring Diagram.
16. If the voltage at terminals B2+ to B3- and B5+ to B6- of the chopper module is significantly higher
than 58 VDC, check for an open R4 load resistor. Also check for damaged conductors or faulty
connections at leads 301 and 302. See Wiring Diagram.
17. If the voltage at terminals B2+ to B3- and B5+ to B6- of the chopper module is very low or not
present, use the frequency counter to check for the presents of a 20 kHz PWM signal between leads
23+ and 25-, where they connect to the chopper module board.
18. If the 20 kHz signal is present, the chopper module is defective, replace.
19. If the 20 kHz signal is not present, perform the Weld Control Board PWM Gate Signal Test
Procedure.
20. If the weld control board is producing a PWM gate signal, check the 23 (B7) and 25 (B8) leads for
damaged conductors and faulty connections between the weld control PC board and the chopper
module.
21. When testing is complete, connect all previously disconnected leads and plugs.
22. Perform the Case Cover Replacement Procedure.
Figure F.13 – Chopper module terminal locations
Ranger® 305G EFI Service Manual
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