Thermal Dynamics MERLIN 6000, Service Manual, Page: 27 / 112

Manual 0-2569 21 SERVICE TROUBLESHOOTING
4. Shorted diode (D11-D14)
a. Check for proper 3-phase power at input termi-
nal board, check diodes. Refer to Section 4.05-
E, Diode Check.
5. Faulty Voltage Selection PC Board
a. If W1 and W2 come on simultaneously replace
Voltage Selection PC Board.
6. Faulty Main Contactor (W1 or W2)
a. Check both contactors for welded contacts and
replace contactor(s) if necessary
G. TEMP indicator on (red)
1. Unit overheated
a. Clean radiator and check for obstruction.
b. Excessive piloting; allow unit to cool
2. Faulty thermal sensor (TS1 to TS5)
a. Refer to Section 4.05-F, Thermal Sensing Circuit
Circuit Check. Replace sensor(s) if necessary
3. Faulty Logic PC Board
a. Refer to Section 4.05-F, Thermal Sensing Circuit
Check. Replace Logic PC Board if necessary
4. Faulty LED/Current Control PC Board
a. Refer to Section 4.05-F, Thermal Sensing Circuit
Check. Replace LED/Current Control PC
Board if necessary.
H. Gas indicator OFF; Plasma gas flowing; Motor
and Pump operating; Other LED indicators
normal; Merlin 6000 Front Panel RUN/SET/
PURGE switch in SET or PURGE posistion
1. Plasma gas pressure set too low
a. Gas pressure less than 35 psi (2.4 bar) prevents
Pressure Switch (PS1) from activating. Refer
to approriate Torch Manual for proper gas pres-
sure settings for the operation.
2. Faulty pressure switch, PS1
a. In the Merlin 6000, connect a jumper wire across
the Pressure Switch (PS1)
• If the gas indicator comes ON, the switch was
faulty
• If gas indicator is OFF, refer to Section 4.05-G,
Pressure Sensing Circuit
3. Faulty Logic or LED/Current Control PCB
a. Refer to Section 4.05-G Pressure Sensing Cir-
cuit
I. Plasma or Secondary Gas does not flow or flow is
too low
1. If Merlin 6000 Front Panel or remote RUN/SET/
PURGE switch are set to PURGE, secondary gas will
not turn ON
a. Set RUN/SET/PURGE switch to SET position.
2. If Merlin 6000 Front Panel Secondary Mode switch
(SW3) is set to O
2
(oxygen) position, secondary gas
will not turn ON
a. For Merlin 6000 Systems do not use O
2
position
3. Inlet gas pressure too high
a. Reduce pressure and try again (see NOTE)
NOTE
Pressure greater than 125 psi may prevent some
gas solenoids from opening
4. No gas at inlet
a. Gas supply turned OFF or tank empty
b. Gas select control on Gas Control (GC 3000) set
to inlet that has no gas connected
5. Clogged torch head or lead
a. Check that the gas hoses are not pinched or
kinked
b. Check torch for correct gas distributor
c. Check gas flow
CAUTION
High pressure gas is dangerous. Reduce plasma
gas pressure to 30 psi (2.07 bar).
• Plasma Gas not flowing?
Remove the plasma gas torch lead hose from the
Arc Starter Box.
Turn ON the power supply, if gas flows, the torch
head is clogged.
• Secondary Gas not flowing?
CAUTION
High pressure gas is dangerous. Reduce second-
ary gas pressure to 30 psi (2.07 bar).
Remove the secondary gas torch lead hose from
the Arc Starter Box.