In Open Circuit Operation, The Output Voltage Is Not Regular - Cebora PLASMA PROF 123 ACC Service Manual

CEBORA S.p.A.

3.3.8 - In open circuit operation, the output voltage is not regular.

POWER SOURCE OUTPUT VOLTAGE TEST.
Power board (56), terminals TP1(+) – TP6(or terminal 1 of igbt module)(gnd) = fig. 5.2.1b
(+160 Vdc approximately) Power Source output voltage with pilot arc on, for 2.5 seconds
(pilot arc maximum time), with start button pressed.
♦ Correct Power Source output voltage.
DRIVER BOARD (56) POWER SUPPLY TEST
Driver board (56), connector J3, terminals 1 - 2 = 20 Vac, with switch (49) closed.
♦ Check the wiring between J3 driver board (56) and J1, terminals 1 and 2 on fuse
board (53).
♦ Check fuse F5 on fuse board (53). Replace if interrupted after having checked,
with Power Source off and J3 disconnected from driver board (56), the resistance
between terminals 1 and 2 of J3 on driver board (56). Correct value = >Mohm in
both directions. If incorrect replace the driver board (56).
♦ Check 20 Vac voltage on terminals 0V-20V on fuse board (53); if lacking check
the wiring between services transformer (53) and fuse board (53) and replace
services transformer (53), if necessary.
PILOT ARC CURRENT REFERENCE TEST.
Driver board (56), connector J3, terminals 5(+) - 4(gnd) = fig. 5.2.4 (+4.4 Vdc approximately)
pilot arc current reference signal, for 2.5 seconds (pilot arc maximum time), with start button
pressed.
♦ Check the wiring between J3 driver board (56) and J3, terminals 5 and 6 on
control board (47).
♦ With Power Source off, temporarily disconnect J3 from control board (47) and
check the resistance on terminals 5 and 4 of J3 on driver board (56). Correct value
= 1.5 Kohm in both measure directions. If incorrect replace driver board (56).
♦ Check the supply voltages of the control board (47), performing, if necessary, the
CONTROL BOARD (47) POWER SUPPLY TEST of par. 3.3.1.
♦ Replace control board (47).
3.302.269
Correct?
NO
Correct?
YES
Correct?
YES
YES
NO
NO
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12/04/2012