Thermal Dynamics cutmaster A60, Service Manual

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CUTMASTER A60
Manual 0-4982 5-13 SERVICE
5.08 Pilot Arc Problems
A. AC LED ON, TEMP LED OFF, GAS LED
ON. Nothing happens when torch switch
or remote switch is closed ( Or CNC
START signal is active) No gas flow, DC
LED OFF.
1. Problem in the torch and leads switch circuit (or
remote pendant or CNC signal missing
a) For hand torches, check continuity of torch
switch circuit at ATC pins 3 & 4.
Negative / Plasma Lead
4 Torch Switch
3 Torch Switch
2 PIP
1 PIP
Pilot Lead
Art # A-08124
b) For machine torches using a remote pendant,
check continuity of Pendant switch circuit
c) For CNC input see section "5.07 H Tip Missing
Fault"
2. Defective Logic PCB
a) Jumper on Main PCB between J2-16 and test
point GND1. If gas does not flow, replace
Logic PCB
b) With Torch Switch closed, measure voltage
on Main PCB between test points GND1 to
I_DMD1 for 1.4VDC. Replace Logic PCB if
voltage is not present.
3. Defective Main PCB
a) With Torch Switch closed, measure voltage
on Main PCB between test points GND1 to
I_DMD1 for 1.4 VDC. Replace Main PCB if
voltage is present.
B. SHORTED TORCH FAULT
After torch switch is closed, gas flows for two (2)
seconds then momentarily shuts OFF then back on,
FAULT INDICATOR flashes, and 85 PSI LED flashes.
1. Upper O-Ring on torch head is in the wrong posi-
tion.
a) Remove shield cup from torch; check position
of the upper o-ring and correct if needed.
Upper Groove
with Vent Holes
Must Remain Open
Threads
Upper O-Ring
in Correct Groove
Lower O-Ring
Art # A-03725
2. Torch start cartridge is stuck.
a) Turn OFF power supply. Bleed down the sys-
tem. Remove the shield cup, tip,start cartridge
and electrode. Check the lower end unit of the
start cartridge for free movement. Replace the
cartridge if the lower end unit does not move
freely.
Art # A-08064_AC
Spring-Loaded
Lower End Fitting
Full Compression
Spring-Loaded
Lower End Fitting at Reset /
Full Extension
3. Worn or faulty torch parts
a) Inspect torch consumables parts. Replace if
necessary.
4. Shorted Torch
a) Disconnect torch from unit. With consumables
removed from the torch, check continuity of
torch at ATC, between negative/plasma lead
connection to pilot lead connection.
Negative / Plasma Lead
4 Torch Switch
3 Torch Switch
2 PIP
1 PIP
Pilot Lead
Art # A-08124