Recommended tests.
increase the voltage generated by the variac up to 24Vac.
A)
Switch on the HV power supply (HV output) and check that the
H)
Set up the oscilloscope with the probe x10 connected between the
precharge relays K1 and K2 on the primary board close with a slight
gate (prod) and emitter (earth) of the IGBT Q3 on the primary board
delay
(figure 5)
.
(figure 5)
. Check that the wave form on the display resembles that in
B)
Use the oscilloscope to check that the voltage waveform between
figure E
.
the collector of Q6 (probe) and rheofore of C47 from the Q3 side
(earth) resembles that shown in figure C.
- repeat this test on Q12 on the primary board.
I)
Switch off the machine and the HV power supply. Also:
- disconnect the HV from the machine,
C)
On the primary board check the following power supply voltages:
- reset the jumper JP2 on the primary board,
- between the cathode of D20 and the anode of D21 equal to +28V
- replace the test wiring between the primary and control boards with
±5%,
the original.
- between the cathode of D12 and the anode of D13 equal to +28V
J)
Switch the machine back on and make sure that it is in alarm status
±5%,
(yellow LED D35 lit up on the panel). Increase the variac voltage to
- between the anode of D11 and case of U3 equal to +12V±5%,
320Vac and make sure the machine is always in alarm status.
- between the anode of D6 and case of U3 equal to +5V±5%,
Continue to increase the variac voltage and check that between the
- between the cathode of D5 and case of U3 equal to –12V±5%.
values of 330Vac and 460Vac (approx.) the machine leaves alarm
B)
Switch off the HV power supply, reposition the control board and
status.
reconnect the wiring with the exception of that between the primary
Finally, bring the variac voltage to 470Vac and make sure the
board (to J1) and the control board (to J3). This should be replaced
machine does not return to alarm status (never take the variac above
with the special test wiring as in figure B (take care to position
the value 475 Vac). Bring the variac immediately back down to
correctly).
400Vac and switch off the machine.
E)
Switch the HV back on and check that:
- the green power supply LED D8 lights up,
- the machine is not in alarm status (yellow LED D35 switched off).
F)
Set up the oscilloscope with the probe x10 connected between the
7) Repairing and replacing the boards
gate (prod) and emitter (earth) of the IGBT Q3 on the primary board
If repairing the boards is complicated or impossible, they should be
(figure 5)
completely replaced. Each board is identified by a 6-digit code (printed
Check that the wave form on the display resembles that in
figure D.
in white on the component side after the initials TW).
This is the reference code for requesting a replacement. Telwin may
supply boards that are compatible but with different codes.
Note:
before inserting a new board check it carefully for damage that
may have occurred in transit. When we supply a board it has already
been tested and so if the fault continues after it has been replaced
correctly, check the other machine components. Unless otherwise
required by the procedure, never alter the board trimmers.
A) Removing the primary board (figure 3)
- Disconnect all the wiring connected to the board and the cables that
are connected from the board to the fans and the power transformer.
NB.
The connections between the primary board and the power
transformer should never be inverted when the new board is
assembled.
- Remove the control board by first removing the potentiometer knobs
on the front panel, disconnecting the wiring and releasing the board
from the 4 plastic columns attaching it to the primary board.
- Undo the 4 screws fastening the primary board to the metallic
structure.
- repeat this test on Q4, Q5, Q12, Q13, Q14 on the primary board.
- Extract the board, rotating it gently upwards from the front panel side
N.B.
If the signal is not present and/or the machine is in alarm status
(this operation is easier if the front panel plate is pulled gently
(yellow LED lit up) there could be a fault in the control board (in which
outwards).
case we recommend its replacement) or in the IGBT driver circuit
NB.
For re-assembly proceed in the reverse order.
(figure 5)
.
G)
Switch off the HV reconnect the 2 fastons between the primary board
Please read the procedure for replacing the IGBT's and/or rectifier
and power transformer (J2 and J8).
bridges carefully:
Switch on the HV and the variac (initially set to the value 0V), switch
Even if only one IGBT is damaged, always replace all 6.
off the main power supply switch on the machine and gradually
Figure C
Figure D
Figure E
Amplitude tollerance:
÷10%
Frequency:
32,5Khz ÷ 10%
Amplitude tollerance:
÷10%
Frequency:
32,5Khz ÷ 10%
Amplitude tollerance:
÷10%
Frequency:
32,5Khz ÷ 10%
SUPERIOR 240 CE
14
