WARNING:
WARNING:
WARNING:
BEFORE PROCEEDING WITH REPAIRS TO THE
MACHINE READ THE INSTRUCTION MANUAL
CAREFULLY.
EXTRAORDINARY MAINTENANCE SHOULD BE
CARRIED OUT ONLY AND EXCLUSIVELY BY
E X P E R T
O R
S K I L L E D
E L E C T R I C A L -
MECHANICAL PERSONNEL.
ANY CHECKS CARRIED OUT INSIDE THE
MACHINE WHEN IT IS POWERED MAY CAUSE
SERIOUS ELECTRIC SHOCK DUE TO DIRECT
CONTACTWITH LIVE PARTS.
GENERAL REPAIR INSTRUCTIONS
TROUBLESHOOTING AND REMEDIES
The following is a list of practical rules which must be strictly
adhered to if repairs are to be carried out correctly.
A) When handling the active electronic components, the
IGBT's and Power DIODES in particular, take
elementary antistatic precautions (use antistatic
footwear or wrist straps, antistatic working surfaces
etc.).
B) To ensure the heat flow between the electronic
components and the dissipator, place a thin layer of
thermo-conductive grease (e.g. COMPOUND
GREASIL MS12) between the contact zones.
C) The power resistors (should they require replacement)
should always be soldered at least 3 mm above the
board.
D) If silicone is removed from some points on the boards, it
should be re-applied.
Use only non-conducting neutral or oximic
reticulating silicones (e.g. DOW CORNING 7093).
Otherwise, silicone that is placed in contact with points
at different potential (rheophores of IGBT's, etc.) should
be left to reticulate before the machine is tested.
E) When the semiconductor devices are soldered the
maximum temperature limits should be respected
(normally 300 C for no more than 10 seconds).
F) It is essential to take the greatest care at each
disassembly and assembly stage for the various
machine parts.
G) Take care to keep the small parts and other pieces that
are dismantled from the machine so as to be able to
position them in the reverse order when re-assembling
(damaged parts should never be omitted but should be
replaced, referring to the spare parts list given at the
end of this manual).
H) The boards (repaired when necessary) and the wiring
should never be modified without prior authorisation
from Telwin.
I)
For further information on machine specifications and
operation, refer to the Instruction Manual.
J)
When the machine is in operation there are
dangerously high voltages on its internal parts so do not
touch the boards when the machine is live.
Every operation should be carried out in complete safety
with the power supply cable disconnected from the mains
outlet and should only by done by expert or skilled
electrical-mechanical personnel.
-
undo the 4 screws attaching the handle to the top cover
(
);
-
undo the 2 screws fastening the two plastic shells to the
base: 1 screw on each side (
-
undo the 2 screws attaching the handle to the base: 1
screw on each side (
);
-
on the top cover undo the nut for the earth connection
(J7);
-
slide out the top cover upwards (
);
-
undo the two screws fastening the power board to the
base.
After completing the repairs, proceed in the reverse order to
re-assemble the cover and do not forget to insert the
toothed washer on the ground screw.
Using suitably dried compressed air, carefully clean the
components of the power source since dirt is a danger to
parts subject to high voltages and can damage the galvanic
separation between the primary and secondary. To clean
the electronic boards we advise decreasing the air pressure
to prevent damage to the components. It is therefore
important to take special care when cleaning the following
parts:
Check whether dirt has been deposited on the front and
back air vents or has damaged the correct rotation of the
blades, if there is still damage after cleaning replace the fan.
Make sure there is no mechanical deformation, dent, or
damaged and/or disconnected connector. Make sure the
power supply cable has not been damaged or disconnected
internally and that the fan works with the machine switched
on. Inspect the components and cables for signs of burning
or breaks that may endanger operation of the power source.
Check the following elements:
Use the multimeter to check whether the contacts are stuck
together or open. Probable cause:
-
mechanical or electric shock (e.g. bridge rectifier or
IGBT in short circuit, handling under load).
Probable cause:
-
mechanical shock.
Probable cause:
-
see main power supply switch.
If the relay contacts
are stuck together or dirty, do not attempt to separate
them and clean them, just replace the relay.
N.B.
WARNING!
fig. 1
fig. 1);
fig. 1
fig. 1
N.B.
1.0 Disassembling the machine
2.0 Cleaning the inside of the machine
3.0 Visual inspection of the machine
Fan (fig. 2A)
Power board figs. 2A and 2B
Main power supply switch (fig. 2A)
Current potentiometer R75 (fig. 3)
Relay K1 (fig. 3)
(
):
°
-
rheofores of IGBT Q1;
-
rheofores of secondary power diode D22;
-
thermostat ST1 on the IGBT;
-
opto-coupler ISO1.
- 10 -
TECNICA 114
