73 - "Th""0" On Displays (U) (V). Transformer (37) High Temperature; 74 - "Th""1" On Displays (U) (V). Power Board (56) Igbt Group High Temperature - Cebora PLASMA PROF 123 ACC Service Manual

CEBORA S.p.A.
♦ With Power Source off, temporarily disconnect J19 from control board (47) and
check the resistance between terminals 1 and 2 of J19 on control board (47).
Correct value = junction of two diodes in both measure directions. If incorrect,
replace control board (47).
♦ Replace the measure board (57).
♦ With Power Source off, temporarily disconnect J2 from measure board (57) and check
resistance between terminals 1-3-5 of J2 on measure board (57). Correct value = 7 Mohm
approximately, between all points and in both measure directions. If incorrect replace the
measure board (57).
♦ With Power Source off, temporarily disconnect J19 from control board (47) and check the
resistance between terminals 1 and 2 of J19 on control board (47). Correct value = junction of
two diodes in both measure directions. If incorrect, replace control board (47).
♦ Replace measure board (57) and control board (47).

3.4.12 - 73 - "TH""0" on displays (U) (V). Transformer (37) high temperature.

3.4.13 - 74 - "TH""1" on displays (U) (V). Power board (56) igbt group high temperature.

With these alarms we recommend that you do not shut off the Power Source, to keep the fan
running and thus cool the unit more rapidly. Normal operation is restored automatically as soon
as the temperature returns within the allowed limits.
− Make sure the fan (23) is working properly, performing if necessary the test in par. 3.3.2.
− Check for proper air flow and make sure there is no dust nor obstacles to cooling the Power
Source internal part.
− Make sure that the operating conditions meet the specification values; especially observe the
"duty cycle".
− Make sure the thermostats on transformer (37) and on power boards (56) igbt group dissipater
are properly fitted and in good working order; at room temperature their contacts must be
closed.
− Check the supply voltage of the control board (47) taking special care for 27 Vac voltage
carrying out the CONTROL BOARD (47) POWER SUPPLY TEST of par. 3.3.1.
− Check the wiring between the thermostat on transformer (37) and J12, terminals 3 and 4 on
control board (47).
− With Power Source off, temporarily disconnect the thermostat on transformer (37). Power up
the Power Source again and check on the patch connectors disconnected from the thermostat,
voltage = 27 Vac, with switch (49) closed (alarm condition). If incorrect, replace control
board (47).
− Check wiring between the thermostat on power board (56) igbt group dissipater and terminal
J4-A and J4-B on power board (56) and between J6 power board (56) and J12, terminals 1
and 2 on control board (47).
− Make sure the continuity between terminals J4-A with J6-2 and between J4-B with J6-1 on
power board (56). If interrupted reset original connections.
− With Power Source off, temporarily disconnect J6 from power board (56). Power up the
Power Source again and check on the patch connector disconnected from J6 voltage = 27 Vac
(alarm condition). If incorrect, replace control board (47).
− Replace control board (47).
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