WARNING:
WARNING:
BEFORE PROCEEDING WITH REPAIRS TO
THE MACHINE READ THE INSTRUCTION
MANUAL CAREFULLY.
EXTRAORDINARY MAINTENANCE SHOULD
BE CARRIED OUT ONLY AND EXCLUSIVELY
BY EXPERT OR SKILLED ELECTRICAL-
MECHANICAL PERSONNEL.
WARNING:
ANY CHECKS CARRIED OUT INSIDE THE
MACHINE WHEN IT IS POWERED MAY
CAUSE SERIOUS ELECTRIC SHOCK DUE TO
DIRECT CONTACT WITH 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 (
);
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.
-
rheofores of IGBT's Q5, Q8;
-
rheofores of recirculating diodes D14, D31;
-
rheofores of secondary power diodes D32, D33, D34;
-
-
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.
Probable cause
-
mechanical shock;
-
machine connected to power supply voltage much higher
than the rated value;
-
broken rheophore on one or more capacitor: the remainder
will be overstressed and become damaged by overheating;
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 R23 fig. 3
Relay RL1 fig. 3
Electrolytic capacitors C21,C22 fig. 3
(
)
(
):
(
)
(
)
(
)
(
)
°
thermostat ST1 on power transformer;
opto-coupler ISO1;
:
- 10 -
TECNICA 144 - 164
