0 v 5 ms 0 volts, Troubleshooting and repair – Lincoln Electric POWER MIG SVM157-A User Manual

Page 59

TROUBLESHOOTING AND REPAIR

F-25

POWER MIG 200

ABNORMAL OUTPUT VOLTAGE WAVEFORM - MACHINE

LOADED (MAX TAP “G”)

ONE OUTPUT DIODE NOT FUNCTIONING

20.0 V

5 ms

0 Volts

This is NOT a typical DC output voltage
waveform. One output diode is not func-
tioning. Note the increased ripple con-
tent. One diode was disconnected to
simulate an open or non-functioning out-
put diode. Each vertical division repre-
sents 20 volts and each horizontal divi-
sion represents 5 milliseconds in time.
The machine was loaded with a resis-
tance grid bank.

NOTE: Scope probes connected at

machine output terminals: (+)
probe to electrode, (-) probe to
work.

Volts/Div.................................20V/Div

Horizontal Sweep.................5 ms/Div

Coupling........................................DC

Trigger....................................Internal

SCOPE SETTINGS

MACHINE LOADED TO 180 AMPS AT 16 VDC