Hypertherm MAX200 Service Manual - Manual (Page 72)

MAX200 Service Manual 3-31
MAINTENANCE
WARNING
SHOCK HAZARD: Use extreme care when working near the chopper modules. The large electrolytic
capacitor(s) (blue-cased cylinder(s)) store largeamounts of energy in the form of electric voltage. Even if
the power is off, dangerous voltages exist at the capacitor terminals, on the chopper, and the diode
heatsinks. Never discharge the capacitor(s) with a screwdriver or other implement…explosion, property
damage and/or personal injury will result.
1. Turn all power to the MAX200 OFF. Disconnect PL26 from REC26 to disable high frequency transformer T5.
See Figure 4-10 for location of T5.
2. Remove large fuses F3 and F4. Check to see if fuse(s) is (are) open.
3. Place the positive lead to the + side of the bridge and the negative lead to the – side of the bridge. See Figure
on page 3-32. Note that actual connection points are hidden by cap support bracket.
4. Turn power to the MAX200 ON, and start system up. After the START command has been given, check voltage.
The input to the chopper at these points should be about +280 VDC.
If the input is OK and corresponding fuse F3 or F4 was blown, replace the chopper module.
If there is no +280 VDC input, check input to bridge for shorts. Also, check contactor (CON1), connections and
associated wiring to the contactor. Repair and/or replace defective component(s) if necessary.
5. If voltage from step 4 is +280 VDC and corresponding fuse is not blown, check the CH1 chopper output at TB1
by putting the positive lead of the voltmeter at the (+) WORK terminal (#48A output cable) and negative lead at
the (-) TORCH (#39A output cable). (Check the CH2 output using the same procedure used checkout CH1. See
Figure on page 3-32
6. Turn the system on and press the START command. After the START command has been given, check the
voltage. If the output from each chopper at these points is +280 VDC, then choppers are OK.
7. If the chopper does not output +280 VDC, check to see if LED1 logic power light is on. If LED1 is not on, check
if 120V is going to JP6. If there is no 120V at JP6, check wiring back to power distribution board. Repair or
replace defective component(s), if necessary.
Also check to see if LED3 is turning green when enabled (normal condition). If LED1 is on and LED3 is red
when enabled (fault condition), then make sure that JP9 is seated properly. If JP9 is connected, disconnect one
side of the thermo switch wire (TS1) and try again. If voltage comes up and LED3 turns green, the unit is either
too hot or thermo switch is shorted. Allow unit to cool and repeat test. If LED3 still turns green, replace chopper
module.
Test Procedures (Cont.)
Chopper Module Test Procedure
The chopper module operation is described earlier in this section under Theory of Operation: “Chopper” Power
Supply. In order to troubleshoot the chopper section for proper functioning, perform the following procedure: