Lincoln Electric Ranger 305D Service Manual page 113

F-59
OUTPUT RECTIFIER BRIDGE TEST ( ontinued)
7. Check for grounds by placing one of the ohm
meter probes on a clean, unpainted metal
surface of the machine.
probe to each of the five rectifier terminals.
The resistance to chassis ground from each
terminal should be very high, 500,000 (500K)
ohms minimum. If the resistance reading is
less than specified, the rectifier is grounded
and should be replaced.
8. If using diode checker or a multimeter with
diode check functionality, read and under-
stand the instructions that accompany your
test equipment.
9. If using an analog ohmmeter, the forward
bias test will indicate low resistance and the
reverse bias test will indicate high resistance.
Precise ohm values for this test will vary
depending on a test equipment used.
POS.
W3
W2
W1
W4,W5
W10
TROUBLESHOOTING & REPAIR
All manuals and user guides at all-guides.com
Touch the other
FIGURE F.16 – SHUNT/RECTIFIER LEADS
NEG.
W6,W11
FROM SHUNT
RANGER 305D
NOTE: A digital Ohmmeter is not recommended
for this test. A typical digital Ohmmeter
does not provide enough voltage or cur-
rent flow to reliably test the diodes used in
this rectifier.
10. Test all of the diode groups per the Table F.1.
TOP
W1
CENTER
W2
W3
BOTTOM
OR
F-59
OUTPUT
RECTIFIER
BRIDGE
CHOKE