Thermal Dynamics SIGNATURE PAK 1250XRTM, Owner'S Manual

Page: 44 / 68

32
SERVICE
4.4 TROUBLESHOOTING GUIDE (continued)
TROUBLE POSSIBLE CAUSE REMEDY
1. Gas supply not turned on,
or empty cylinder
2. Faulty solenoid (SOL)
3. Faulty RUN/SET switch
(SW2)
1. Gas pressure too low
2. Faulty status light PC
board
1. Faulty regulator or
plugged filter
2. Supply line too low
D. No gas flow in SET
position
E. GAS indicator not lit in
SET position
F. Cannot set desired gas
pressure
1. Turn gas supply on, or
replace cylinder.
2. Check and replace sole-
noid if necessary.
3. Check and replace switch
if necessary.
1. Reset to 40 psi (2.8 bar)
plasma, 75 psi (5.2 bar)
secondary.
2. Check and replace PC
board if necessary.
1. Repair or replace.
2. Check input pressure.
When the torch switch is pressed the gas should start to flow and the GAS indicator should
come on. Two seconds later, the main contactor (W) should close (red DC indicator lit), fol-
lowed by the closing of the high frequency relay (HF indicator lit). At this time the pilot arc
should be established. If this does not happen, check to see if (1) there is any light visible inside
the torch, and (2) the red HF indicator is lit.
TROUBLE POSSIBLE CAUSE REMEDY
1. Check wires to plug,
switch, and receptacle.
2. Check switch for continu-
ity when pressed.
3. Check and replace PC
board if necessary.
1. Move to RUN position.
2. Check connections and
correct if necessary.
3. Check main contactors
(see A, page 35).
4. Check diodes (see E, page
35).
1. Replace control logic PC
board.
2. Normal operation.
G. No gas flow when torch
switch pressed
H. No red DC indicator (gas
flows)
I. Pilot arc comes on imme-
diately (without two
second pre-flow delay)
1. Torch switch not con-
nected
2. Torch switch not closing
3. Faulty control logic PC
board
1. RUN/SET switch in SET
position.
2. Loose control logic PC
board connection
3. Faulty main contactor
(W1, W2, or W3)
4. Diodes failed in main
bridge rectifier
1. No pre-flow delay
2. Unit still in ten second
post flow mode