7.UNITS B-70315EN/02
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Fig. 7.2.1 Layout of diodes and FET module PCBs
7.2.1.3 Replacing an FET module PCB
(1) Turn off the power to the CNC, and turn off the main circuit
breaker of the oscillator.
(2) Remove the water fittings, and power and signal cables.
(3) Remove the mounting screws on the top plate of the laser power
supply unit, and remove the top plate.
(4) As shown in Fig. 7.2.1, you can see the two FET module PCBs
and the diode unit.
(5) Check for a damaged element, and replace it.
(a) Checking an FET module PCB
Measure the resistance across check pins D and S shown in
Fig. 7.2.1. If the resistance is several kilo-ohm, the PCB is
regarded as being damaged. (The resistance of a normal
FET module PCB is several tens kilo-ohms to several
mega-ohms.)
(6) After PCB replacement, power supply adjustment is unnecessary.