Hypertherm Powermax1250 Service Manual - Manual (Page 34)

powermax1250 Service Manual 3-1
Section 3
MAINTENANCE
In this section
Controls and indicators .............................................................................................................................................3-3
Indicator LEDs..................................................................................................................................................3-3
Theory of operation...................................................................................................................................................3-4
General ............................................................................................................................................................3-4
Functional description ......................................................................................................................................3-4
Sequence of operation .....................................................................................................................................3-5
Troubleshooting preparation .....................................................................................................................................3-6
Test equipment.................................................................................................................................................3-6
Troubleshooting procedures and sequence .....................................................................................................3-6
External inspection...........................................................................................................................................3-6
Internal inspection ............................................................................................................................................3-7
Initial resistance check..............................................................................................................................................3-7
Check the power switch ...................................................................................................................................3-8
Hypertherm IGBT tester ...................................................................................................................................3-9
Indicator LEDS and device tests ......................................................................................................................3-9
IGBT test preparation .....................................................................................................................................3-10
IGBT device test using the Hypertherm tester ...............................................................................................3-10
Troubleshoot the Hypertherm IGBT tester .....................................................................................................3-11
Schematic for building an IGBT tester............................................................................................................3-11
IGBT device test using a non-Hypertherm tester ...........................................................................................3-12
Troubleshooting guide ............................................................................................................................................3-14
Control board LEDs........................................................................................................................................3-20
Test 1 – voltage input .....................................................................................................................................3-22
Test 2 – voltage balance ................................................................................................................................3-23
Test 3 – output diodes ....................................................................................................................................3-24
Test 4 – pilot arc IGBT (Q8) ...........................................................................................................................3-25
Test 5 – inverter IGBT (Q6) and PFC IGBT (Q7) ...........................................................................................3-26
Test 6 – flyback circuit ....................................................................................................................................3-27
Test 7 – torch stuck open (TSO) ....................................................................................................................3-28
Test 8 – plasma start ......................................................................................................................................3-29
Test 9 – torch cap sensor ...............................................................................................................................3-29
Test 10 – gas solenoid ...................................................................................................................................3-30
Test 11 – incoming line voltage (VACR) .........................................................................................................3-30
Test 12 – pressure switch...............................................................................................................................3-30
Test 13 – fan...................................................................................................................................................3-30