Hypertherm MAX200 Service Manual - Manual (Page 73)

3-32 MAX200 Service Manual
3-00
MAINTENANCE
8. If chopper still does not output 280V after completing step 7, there may be a problem with the control signal or
the chopper module. The chopper drive signal comes through control board PCB7 as an analog level from 0 to
+8 VDC, which varies the duty cycle and subsequent output current of the chopper. These analog signals are on
pins 3 & 4 REC3 of PCB7 for CH1, and 5 & 6 REC3 for CH2.
To determine if there is a problem with the chopper modules or with control board PCB7, proceed as follows:
• Ensure that high frequency is still disabled (see step 1).
• Disconnect PL7 from REC3 on PCB7.
• Place voltmeter across output terminals of chopper (positve lead to (+) WORK and negative lead to (-)
TORCH) and press the START command.
• If the voltmeter reads +280 VDC, replace control board PCB7.
• If the voltmeter reads 0 volts, replace corresponding chopper module CH1 or CH2.
LED1
JP9
LED3
Thermo
Switch
TS1
Bridge (–)
Bridge (+)
JP6
(+) WORK
(-) TORCH
C H O P P E R . 0 1
Input