SECTION 6
PCM-875A Plasmarc System
Troubleshooting
6-9
6.3
Reference Voltage Checks
A. Control Board Assembly (PCB1)
LED’s
LED-1 - Torch
Switch
LED-2 - High
Frequency
LED-3
-
Gas Solenoid Valve
Voltage Test Points
Tests are made with power on - no arc.
Disable High Frequency by disconnecting blue wire
with black sleeve
TP-0 -
Ground
TP-1 -
+15
vdc
TP-2 -
+12
vdc
TP-3 -
-12
vdc
TP-4 -
+5
vdc
TP-9
-
IGBT’s driving signal - switching
frequency = 16 KHz
TP-10 -
IGBT’s driving signal - switching
frequency = 16 KHz
13 vdc
-13 vdc
5 msec
62 µsec
0
IGBT Gating Signal
For 208/230 VAC input, the IGBT off time is 3msec.
For 400/460/575 VAC input, the IGBT off time is 6msec.