Tweco SC11 - Manual (Page 34)

CUSTOMER/OPERATOR SERVICE 5-6 Manual 0-2556
• If correct, the Standoff Control is faulty.
• If voltage is not correct, check the voltage from
the type plasma power supply per one of the fol-
lowing:
Merlin 1000 Systems
This check is for Merlin 1000power Supplies with-
out the Filter/Voltage Divider PC Board. If the Mer-
lin 1000 has the Filter/Voltage Divider PC Board, then
refer to Automated Systems.
WARNING
Use extreme caution as high voltage is present.
Main arc voltage, typically minus 100 to 200 vdc is
present on the Pilot/Output PCB at E3 (-) and E8(+).
It is converted to a positive 6 to 12 vdc between J12
pin 15 (+) and J12 pin 16 (-). Measure for 6 to 12 vdc
between J12-15 (+) to J12-16 (-).
• If voltage is not correct then the Pilot/Output PC
Board is faulty.
• If voltage is correct, check the following:
a. Open connection between J12-15 and J22-6
(wire #91).
b. Open connection between J12-16 and J22-5
(wire #92).
c. Open in the Power Supply Torch Control Cable
between J22-5 and J22-6.
NOTE
Torch Control Connector, J22, is located on the
Plasma Power Supply internal torch connection
bulkhead.
Automated Sytems
This check is for Merlin 1000 Systems With Filter/
Voltage Divider PC Board, Automated Pak Master
75XL Plus, Automated Pak MAster 100XL Plus and
Automated Pak Master 150XL Power Supplies.
WARNING
Use extreme caution as high voltage is present.
Automated power supplies generate the arc voltage
signal on the Filter/Voltage Divider PC Board. Main
arc voltage, typically minus 100 to 200 vdc is present
on the Filter/Voltage Divider PCB at J23-1 (-) and
J23-4 (+). It is converted to a positive 6 to 12 vdc
between J24-12 (+) and J24-14 (-). The wires from J24
go to J22, CNC Interface Connector, on the power sup-
ply rear panel. Connection J24-12 goes to J22-6 (wire
#69) and connector J24-14 goes to J22-5 (wire #68).
Measure for 6 to 12 vdc between J24-12 (+) to J24-14
(-).
• If voltage is not correct then the Filter/Voltage Di-
vider PC Board may be faulty. Make the follow-
ing checks:
a. Check for 20 to 30 vdc (power for the voltage
circuit) between J23-7 (+) to J23-4 (-).
• If voltage is correct, check for minus 100 to
200 vdc arc voltage (while cutting) between
J23-1 (-) to J23-4 (+).
• If both the 20 to 30 vdc and minus 100 to
200 vdc are correct, then the Fiter/Voltage
Divider PC Board is faulty.
• If voltage is correct, check the following:
a. Check connections to Power Supply CNC In-
terface Control Connector J22, pins 5 and 6.
b. Open in Power Supply CNC Interface Con-
trol Cable pin 5 or 6.
NOTE
CNC Interface Control Connector, J22, is located
on the Plasma Power Supply Rear Panel.
H. Motor/Tachometer Tests
Move torch up and down manually in both high and
low speed. If lifter operates at high speed in both
cases either the motor tachometer or connections from
it may be open. Measure voltage between J10-4 and
J10-5. If voltage is approximately 10 to 15 vdc either
plus or minus the motor is okay, replace the Standoff
Control Assembly. If near zero, repeat the measure-
ment at the motor.
The motor has two sets of brushes, the set to the rear
is for the tachometer. If this also is near zero with the
motor moving replace the motor/tachometer. Oth-
erwise check for faulty connections between the mo-
tor and J10 (lifter assembly connector, motor cable,
J43 to J10 harness).