Lincoln Electric PRECISION TIG SVM186-A Service Manual page 75

F-35
TYPICAL OUTPUT VOLTAGE WAVEFORM
HIGH VOLTAGE / HIGH FREQUENCY can damage test equipment.
• Perform all voltage and waveform checks with high frequency circuit OFF.
• Perform High Frequency Disable Procedure.
____________________________________________________________________
TROUBLESHOOTING AND REPAIR
AC STICK MODE
CAUTION
MACHINE LOADED TO 180 AMPS AT
26VDC.
This is the typical AC output voltage wave-
form generated from a properly operating
machine. Note that each vertical division
represents 10 volts and that each horizontal
division represents 2 milliseconds in time.
The machine was loaded with a resistance
grid bank. The grid load meters read 180
amps and 26VDC
Note: Scope probes connected at machine
output terminals: (+) probe to electrode, (–)
probe to work.
SCOPE SETTINGS
Volts/Div.....................50V/Div.
Horizontal Sweep .....2 ms/Div.
Coupling.............................DC
Trigger.........................Internal
PRECISION TIG® 225
- MACHINE LOADED
2ms
F-35
50 volts
0 volts