Firepower, a Thermadyne Company FIREPOWER FP-82 - Manual (Page 31)

Manual 0-2871 4-13 SERVICE
E. Gas Solenoid Circuit Test
Make the following voltage checks and replace the faulty
part as required.
1. Place the RUN/SET Switch to the SET position.
2. Measure for 28 VAC across Solenoid wires #8 and
#9. Refer to System Schematic in Appendix Sec-
tion.
• If 28 VAC is present, replace Solenoid/Pressure
Switch Assembly.
• If 28 VAC is not present, check for 70 psi (4.8
bar) at the pressure regulator.
3. Check for less than 2 vdc at P1-14 to TP1 on Logic
Board.
• If less than 2 vdc, replace Main PC Board.
• If more than 2 vdc, replace Logic PC Board.
F. Output Power Tests
1. No DC Output
Activate the torch.
• If INV ON indicator D21 on Logic PC Board does
not turn ON, then replace the Logic PCB.
• If the INV ON indicator D21 blinks ON then OFF
immediately, perform the following test:
a. Disconnect J28 from the CD PC Board to dis-
able the CD signal.
WARNING
Connector J28 on the CD PC Board must be dis-
connected to prevent electrical damage to measur-
ing equipment when testing the open circuit volt-
age (OCV).
b. Activate the torch. Logic PC Board Inverter
ON Indicator, D21, turns ON.
c. Measure open circuit voltage between E61(+)
to E43(-) on the Power Output PC Board. Volt-
age should be 200-300 Volts. If voltage is less
than 10 V, each
IGBT Module and Output Di-
ode Module should be tested individually.
WARNING
The following tests must be performed with the
power supply connected to primary input power.
There are extremely dangerous voltage and power
levels present inside this unit. Do not attempt to
diagnose or repair without proper training in power
electronics measurement and troubleshooting tech-
niques.
c. Activate the torch.
• After 2 seconds D21 on the Logic PCB should
turn ON. If D21 does not turn ON, replace
Logic PCB.
d. Measure open circuit voltage between E61(+) to
E43 (-) at the Output Power PC Board. Voltage
should be greater than 200 V. If voltage is less than
10 V, refer to the output diode test measurements
or IGBT module test measurements or shorted
torch measurements.
4. Gate Drive & DC Sensing
a. After checking all previous steps in Subsection
4.10-G, jumper TP1 to TP7 on the Logic PCB. Re-
fer to Appendix 3.
b. When the unit is turned on, the DC light
should remain ON.
c. Activate the torch. After two seconds INV ON
Indicator on the Logic PCB should come on and
remain on.
• If INV ON indicator does not remain on, re-
place Logic PCB.
• If INV ON indicator remains on, then check
for approximately 6 vdc between TP-1 to TP-4
and between TP-1 to TP-8 on the Logic PCB.
Refer to Appendix 3.
• If no voltage, replace Logic PC Board.
• If voltage is correct, measure for approxi-
mately 6 vdc between points as in the fol-
lowing chart:
E11 J2A E11 J2B
E19 J10A E19 J10B
IGBT A IGBT B
• If voltage is 0, replace Main PCB.
• If voltage is correct, proceed to the fol-
lowing step.