Tweco Troubleshooting Power Supply - Manual (Page 32)

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the J6 connector. You cannot test this by disconnecting J6 or the black
and blue wires as this will set the 2-5, DC Output Low code which
gets set first.
o User installed equipment.
User Installed Equipment
For user installed equipment to cause 2-7 code it would have to be connected
on the output (to the rear) of the current sensors. To test, disconnect user
equipment and apply CNC START. If code 2-7 is gone user equipment was
defective or connected incorrectly.
Current
sensors
Current sensors HCT1 & 2 are Hall Effect linear current sensors. Their
voltage supply, + and – 15 VDC, and their outputs are connected to CN3 (pilot)
and CN4 (work) on PCB5,WK-5602A. With unit turned on and in idle (Start not
on) measure CN3-3 and CN4-3 (PCB5 TP0 common) for zero volts. If not zero,
check for +15 VDC on pin 1 and -15 VDC on pin 2 of each connector on the
harness that plugs into the sensor. Pin 4 of each connector is common. If +/- 15
VDC OK, sensor whose output is not zero is defective. If +/- 15 VDC is not OK
see section on system bias supply.
PCB5
PCB5 puts out active low signal, “/Arc Transferred”, on CN11-3 (J36-3) when
there is current measured in the Work lead and active low signal “/Pilot ON” on
CN11-4 (J36-4) when current is detected in the Pilot output. During idle, when
CNC START is not on, these signals should be high (+15 VDC). If code is 2-8,
check for +15 VDC at J36-4 (common TP1 on CCM). ). If code is 2-9, check for
+15 VDC at J36-3 (common TP1 on CCM). If either of these is low, PCB5 may
be defective.
o Code 2-8 or 2-9:
Check for + 15 VDC at TP2 and – 15 VDC at TP3 (TP0 common) on
PCB5. The +& - 15 VDC measured above when checking the current
sensors comes from this board so if you checked it above not necessary to
do so again. If voltages are OK, PCB5 is bad. If either voltage is missing
see section on system bias supply.
o Code 2-7:
PCB5 also takes the analog signal from each sensor, adds them and puts
out signal Output Current on CN11-1 (J36-1), an analog signal on whose
level is scaled 0-10V = zero to power supply MAX amps. During idle and
preflow signal here should be 0 VDC, if not PCB5 is bad.
CCM If signals “/Arc Transferred” and “/Pilot ON” were high above and the
analog Output Current signal is zero V. and CCM still causes code 2-7, 2-
8 or 2-9 CCM is defective.