In Open Circuit Operation, The Output Voltage Is Not Regular - Cebora TRI STAR MIG 1635/M Service Manual

CEBORA S.p.A.

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

OPEN-CIRCUIT OUTPUT VOLTAGE TEST.
Output terminal –(G) power source (-) and output terminal +(H) power source (+) = voltages
per table:
Process
MIG
TIG
MMA
♦ Correct operation.
DC-CAPACITORS PRECHARGE TEST.
Power board (32), connector J6, terminals 1(+) and 4(-), voltage = +320 Vdc approximately,
constant also during output voltage generation time, as an example during table conditions.
♦ Make sure power board (32) power supply, performing, if necessary, tests of par.
3.3.1.
♦ Check wiring between J1 control board (29) and J1 power board (32).
♦ With power source off, temporarily disconnect connector J1 from control board
(29) and make sure the resistance between terminal 3 of the connector
disconnected from J1 and terminals 3 of J7 on control board (29) (precharge rele
coil). Corrected value = approximately 1 Kohm in both measure senses. If not
correct check the wiring between J7 control board (29) and J4 power board (32)
and, if necessary, replace the RL1 rele and check the PTC1conditions on power
board (32).
♦ Replace power (32) and/or control (29) boards.
♦ Check connection between diode group heat sink on power board (32), inductor (28) and
power source +(H) output terminal, and between TP9 on power board (32) and power source
–(G) output terminal. If you find loose connections, tighten and replace any damaged
components.
♦ Check wiring between J7 and J3 of control board (29) and J4 of power board (32), between J1
of control board (29) and J1 power board (32), power source +(H) output terminal and J7 of
power board (32). If you find loose connections, tighten and replace any damaged
components.
♦ Make sure control board (29) power supply performing, if necessary, the CONTROL
BOARD (29) POWER SUPPLY TEST, par. 3.3.1.
♦ Replace power (32) and/or control (29) boards.
3.302.233
Voltage
+109 Vdc
+95 Vdc Power source powered or start button pressed
+109 Vdc
Correct?
NO
Correct?
YES
Condition
Start button pressed
Power source powered
YES
NO
13
22/09/2008