Service manual

F-34
TROUBLESHOOTING AND REPAIR
POWER MIG 255C
F-34
0 VOLTS
20.0 V 5 ms
ABNORMAL OPEN CIRCUIT VOLTAGE
OUTPUT CAPACITOR BANK NOT FUNCTIONING
This is NOT the typical DC output voltage
waveform. The output capacitors are not
functioning. Note the lack of “filtering” in the
output waveform. The output capacitor bank
was disconnected. Each vertical division
represents 20 volts and each horizontal divi-
sion represents 5 milliseconds in time.
NOTE: Scope probes connected at machine
output terminals: (+) probe to electrode, (-)
probe to work.
Volts/Div . . . . . . . . . . . . . . . . . . 20 V/Div
Horizontal Sweep . . . . . . . . . . 5 ms/Div
Coupling . . . . . . . . . . . . . . . . . . . . . . DC
Trigger . . . . . . . . . . . . . . . . . . . . Internal
SCOPE SETTINGS
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