TROUBLESHOOTING & REPAIR
F-72 F-72
RANGER 305D
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WELD CONTROL FEEDBACK TEST (continued)
TEST PROCEDURE
1. Place the idle switch in the “HIGH IDLE”
position.
2. Place the mode switch in the “CC-STICK”
position.
3. Place the weld terminals switch in the
“WELD TERMINALS ON” position.
4. Make sure that nothing is plugged into either
Amphenol receptacle.
5. Connect the resistive load bank and the
ammeter to the weld output terminals per
the equipment manufacturerʼs instructions;
also connect the voltmeter probes across
the weld output terminals.
6. Start the machine and, apply a load of about
200 Amps, as shown on the external amme-
ter. If the machine will not produce 200
amps, apply as much load as you can.
7. Compare the readings shown on the exter-
nal ammeter and voltmeter to the amps and
volts displayed on the front panel of the
machine.
8. If the readings shown on the front panel dis-
plays are about the same or very close to
the reading on the external meters, the
feedback is probably good, and this test is
complete.
9. If the readings differ significantly,continue
with this procedure
10. Turn off the engine and release the load
from the weld terminals. (The load bank
and ammeter should remain connected, but
the load should be released.)
11. Perform the Case Cover Removal
Procedure.
12. Locate plugs P3 and P6 on the control PC
board. See figure #1. Remove the plugs
and check for dirt, corrosion, damaged,
expanded, or incorrectly positioned termi-
nals. Repair or replace wiring components
as needed and reconnect the plugs to the
control board.
13. Restart the machine and apply a load
across the weld terminals that measures
about 200 amps. If the machine will not
produce 200 amps of current, apply as
much load as you can.
14. Using the voltmeter, measure and note the
DC voltage at the weld output terminals.
15. Check the voltage between leads #204S+
(P6-1) and lead #208B- (P3-15) at the control
PC board Molex plugs. The voltage should
be the same as was measured at the weld
terminals.