Lincoln Electric IDEALARC SP-255 Service Manual page 86

F-33
TYPICAL SCR GATE VOLTAGE WAVEFORM
This is a typical SCR gate pulse voltage
waveform. The machine was in an open cir-
cuit condition (no load) and operating prop-
erly. Note that each vertical division
represents 2 volts and each horizontal divi-
sion represents 5 milliseconds in time.
Note: Scope probes connected at Plug J3 on
the control board. The (+) probe to lead G2,
and the (-) probe to lead 204.
TROUBLESHOOTING & REPAIR
IDEALARC
SCOPE SETTINGS
Volts/Div . . . . . . . . . . . . . . . . . . .2 V/Div.
Horizontal Sweep . . . . . . . . . .5 ms/Div.
Coupling . . . . . . . . . . . . . . . . . . . . . .DC.
Trigger . . . . . . . . . . . . . . . . . . . .Internal.
® SP-255
F-33