CUTMASTER 60i
Manual 0-5475 SERVICE
5-25
2. Pull torch trigger or apply Start, nothing happens. (Trigger or Start problem).
a. START LED (D643) on the Inverter board should come on when the torch trigger is on or CNC Start (if
equipped) is applied. If it does not measure voltage at J607-3(+) to J607-4 or work lead (common). Volt-
age should be high, 12 to 15V, with the trigger/Start off and go to near zero with the trigger/Start on.
i. If it’s a manual torch and voltage remains high likely a problem with the torch, try another if available
or check for continuity at the torch ATC pins 3 to 4 when the trigger is pulled. If no continuity, torch is
faulty, possibly pins in the ATC or QD (torch handle quick disconnect) are pushed back. If continuity go
to “c.”
b. If it is an automation unit using the Automation Interface board and applying START at the rear panel
CNC connector, jumper pin 3 to pin 4.
WARNING!
The torch may pilot! If the START LED lights problem was in the CNC..
c. If when jumping CNC pins 3 to 4, or there was continuity in step a., and the START LED does not light
then go to J607 and jump pins 3 to 4.
WARNING!
The torch may pilot!
If it still doesn’t light replace Inverter board. If it does light but nothing else happens, no gas flow, replace
the Control & Display board.
3. No pilot, rapid cycling of gas, about once a second (no DC)
You can confirm that the issue is no DC by going to sub section 5:10 Advanced Features Menu and selecting
display of output volts. At idle it shows about 12V, it’s actually negative 12 but the sign isn’t shown, then when
you pull the torch trigger, if no DC, it will show zero or less than 12V as the gas cycles on and off.
a. One cause of no DC in too much current in the main transformer primary. This will latch on a red LED
(D159) on the back of the Control & Display board. It will stay on until the torch trigger (Start) is recycled
and will light again if the fault is still present. Cause can be a problem with the main transformer or the
Inverter board.
i. Inspect the transformer for broken or cracked ferrite cores. Also make the transformer leads are not
shorting to anything. There could still be an internal problem that can’t be detected without special
instruments.
ii. If there are no obvious problems with the transformer the Inverter board may be at fault. If you haven’t
already performed the resistance tests in the first section, Resistance and Diode Tests, go back and
perform steps 5 & 6.
iii. If no fault found, it still could be either an internal fault, such as shorted turns in the transformer or
a problem on the Inverter board. You may have to replace both or one at a time to find the problem.
b. If D159 is not being lit another likely cause of no DC is a defective Inverter board. However PWM signals
that control the Inverter board power output come from the Control & Display board on pins 1 & 3 of
the ribbon cable.
i. You can get an idea if the signals are present by measuring from the work lead (common) to J603-3.
There is no wire in pin 3 so you may need to extend your meter probe to fit through the empty plug
position to contact the pin in the header. At idle this voltage should be about zero and with the torch
trigger pulled will be above zero by some amount. If so, you are getting the PWM signals and the
cause of no DC output is likely the Inverter board. Replace Inverter board.
c. If the voltage at J603-3 does not change, while it is still possible the fault is in the Inverter board, it is
more likely that the Control & Display board is at fault. Also the ribbon cable (removing both ends) for
shorts pin 1 to 2 and pin 3 to both 2 and 4. If the ribbon is OK replace the Control & Display board.
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