Gas Flows From The Torch, The Pilot Arc Does Not Light (Nozzle Voltage Missing) - Cebora PLASMA PROF 164 HQC Service Manual

CEBORA S.p.A.

3.3.6 - Gas flows from the torch, the pilot arc does not light (nozzle voltage missing).

POWER SOURCE OUTPUT VOLTAGE TEST.
Pilot arc board (58), terminals TP3(+) – TP7(-) = approximately +280 Vdc, for a duration of 1
second (maximum pilot arc time) after pressing the start command.
♦ Go to par. 3.3.8.
NOZZLE VOLTAGE TEST.
Pilot arc board (58), terminals J5(+) – TP7(-) = approximately +280 Vdc, for a duration of 1
second (maximum pilot arc time), after pressing the start command.
♦ Go to par. 3.3.7.
PILOT ARC BOARD (58) POWER SUPPLY TEST.
Pilot arc board (58), connector J4, terminals 1 – 2 = 20 Vac.
♦ Check the wiring between J4 of pilot arc board (58) and J1 of fuse board (50).
♦ Check fuse F6 on fuse board (50); if broken, replace and make sure that terminals
1 - 2 of J4 on pilot arc board (58) are not short-circuited.
♦ Check 20 Vac voltage on terminals TP7 - 20V of fuse board (50); if missing,
check the wiring between the service transformer and fuse board (50), and if
necessary replace the service transformer (50).
NOZZLE IGBT COMMAND TEST.
Pilot arc board (58), connector J4, terminals 4(+) - 5(-) = approximately +3.7 Vdc, for 1 sec.
(maximum pilot arc time), with start command activated.
♦ Check the wiring between J4 pilot arc board (58) and J15 control board (38).
♦ With Power Source off, temporarily disconnect J15 from control board (38) and
check the resistance on terminals 4 and 5 of J4 on pilot arc board (58). Correct
value = approximately 10 Kohm. If different, replace pilot arc board (58). If short-
circuited, also replace control board (38).
♦ Replace pilot arc (58) and/or control (38) boards.
♦ Replace the pilot arc board (58).
3.302.218
Correct?
YES
Correct?
NO
Correct?
YES
Correct?
YES
NO
YES
NO
NO
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9/8/2006