Cebora SOUND MIG 3840/T Pulse Service Manual page 17

CEBORA S.p.A.
POWER SUPPLY TEST.
Flyback board (539), connector J5, terminals 1 (+) and 4 (-) = +540 Vdc.
♦ Check the wiring between J5 flyback board (539) and J6 pre-charge board (562).
♦ After waiting for the DC-capacitors (561) to completely discharge,
temporarily disconnect connector J5 on flyback board (539). Power up the power
source again and check the voltage on the terminals Vdc+1 (+) and Vdc-1 (-) of
pre-charge board (562) = +540 Vdc. If correct, replace the flyback board (539).
♦ After waiting for the DC-capacitors (561) to completely discharge,
temporarily disconnect the wires from the + and - terminals of the DC-capacitors
(561) and check the resistance between the + and - terminals of the DC-capacitors
(561). Correct value = >Mohm in one direction, and junction of two diodes with
the probes reversed (NOTE: while measuring, the instrument display reaches the
final value slowly, due to the DC-capacitors (561)). If correct replace the pre-
charge board (562). If incorrect, identify which of the following components is
short-circuited or leaking: DC-capacitors (561), igbt modules (548), discharge
resistors (552), snubber capacitors mounted on the terminals 2 and 3 of the igbt
(548).
FLYBACK BOARD (539) POWER SUPPLY TEST.
Flyback board (539), connector J5, terminals 3 (+) and 4 (-) = +18 Vdc.
♦ Check the wiring between J5 flyback board (539) and J6 pre-charge board (562).
♦ After waiting for the DC-capacitors (561) to completely discharge,
temporarily disconnect connector J5 on flyback board (539) and check the
resistance between terminals 3 (+) and 4 (-) of J5 flyback board (539). Correct
value = >Mohm in one direction, and junction of a diode with the probes reversed.
If correct replace the pre-charge board (562). If incorrect replace the flyback
board (539).
♦ Replace the pre-charge (562) and/or flyback (539) boards.
MOTOR CONTROL BOARD (232) POWER SUPPLY TEST.
Motor control board (232), connector J18, terminals 1 (+) - 6 (-) = +55 Vdc.
♦ Check the wiring between J18 motor control board (232), connector (206) on wire
feeder, connector (506) on power source and J3 flyback board (539).
♦ With the power source off, temporarily disconnect the connector J18 on motor
control board (232) and check the resistance between terminals 1 - 6 of J18 on
motor control board (232). If short-circuited, replace the motor control (232) and
flyback (539) boards.
3.302.191
Correct?
YES
Correct?
YES
Correct?
YES
NO
NO
NO
17
15/02/05