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84
Repair Tips
0. Warning
All ICs and many other semi-conductors are susceptible to
electrostatic discharges (ESD). Careless handling during
repair can reduce life drastically. When repairing, make sure
that you are connected with the same potential as the mass
of the unit via a wrist wrap with resistance. Keep components
and tools also at the same potential !
1. Servicing of SMDs (Surface Mounted Devices)
1.1 General cautions on handling and storage
- Oxidation on the terminals of SMDs results in poor soldering.
Do not handle SMDs with bare hands.
- Avoid using storage places that are sensitive to oxidation
such as places with sulphur or chlorine gas, direct sunlight,
high temperatures or a high degree of humidity. The
capacitance or resistance value of the SMDs may be
affected by this.
- Rough handling of circuit boards containing SMDs may
cause damage to the components as well as the circuit
boards. Circuit boards containing SMDs should never be
bent or flexed. Different circuit board materials expand and
contract at different rates when heated or cooled and the
components and/or solder connections may be damaged
due to the stress. Never rub or scrape chip components as
this may cause the value of the component to change.
Similarly, do not slide the circuit board across any surface.
1.2 Removal of SMDs
- Heat the solder (for 2-3 seconds) at each terminal of the
chip. By means of litz wire and a slight horizontal force,
small components can be removed with the soldering iron.
They can also be removed with a solder sucker (see Fig.
1A)
While holding the SMD with a pair of tweezers, take it off gently using the
soldering iron's heat applied to each terminal (see Fig. 1 B).
- Remove the excess solder on the solder lands by means of
litz wire or a solder sucker (see Fig. 1C).
1.3 Caution on removal
- When handling the soldering.iron. use suitable pressure and be careful.
- When removing the chip, do not use undue force with the pair of tweezers.
- The soldering iron to be used (approx. 30 W) should
preferably be equipped with a thermal control (soldering
temperature: 225 to 250 C).
- The chip, once removed, must never be reused.
1.
4
Attachment of SMDs
- Locate the SMD on the solder lands by means of tweezers
and solder the component on one side. Ensure that the
component is positioned correctly on the solder lands (see Fig.2A).
- Next complete the soldering of the terminals of the
component (see Fiq. 2B).
2. Caution when attaching SMDs
- When soldering the SMD terminals, do not touch them
directly with the soldering iron. The soldering should be
done as quickly as possible, care must be taken to avoid
damage to the terminals of the SMDs themselves.
- Keep the SMD's body in contact with the printed board when
soldering.
- The soldering iron to be used (approx. 30 W ) should
preferably be equipped with a thermal control (soldering
temperature: 225 to 250 C).
- Soldering should not be done outside the solder land.
- Soldering flux (of rosin) may be used, but should not be
acidic.
- After soldering, let the SMD cool down gradually at room
temperature.
- The quantity of solder must be proportional to the size of the
solder land. If the quantity is too great, the SMD might
crack or the solder lands might be torn loose from the
printed board (see Fig. 3).
Fig.3 Examples
Right
190X7&170X7 LCD
190X7&170X7 LCD
Содержание HUSON7 Series
Страница 8: ...8 190X7 170X7 LCD Go to cover page On Screen Display Only available for Europe Model ...
Страница 9: ...9 190X7 170X7 LCD Go to cover page On Screen Display Only available for Nafta Model ...
Страница 10: ...10 190X7 170X7 LCD Go to cover page On Screen Display Only available for Asia Pacific Model ...
Страница 17: ...17 190X7 170X7 LCD Go to cover page Trouble Shooting ...
Страница 18: ...190X7 170X7 LCD Trouble Shooting ...
Страница 46: ...46 190X7 170X7 LCD Go to cover page Go to cover page Wiring Diagram 190X7 1 30 11 1 12 1 1 2 11 1 ...
Страница 50: ...Scaler Diagram 190X7 170X7 LCD ...
Страница 51: ...Scaler Diagram 51 190X7 170X7 LCD 190X7 170X7 LCD ...
Страница 52: ...Scaler Diagram Go to cover page 190X7 170X7 LCD 52 ...
Страница 53: ...Scaler Diagram 53 190X7 170X7 LCD ...
Страница 54: ...54 Go to cover page Scaler Board C B A 190X7 170X7 LCD 190X7 170X7 LCD ...
Страница 55: ...Scaler Board C B A 55 190X7 170X7 LCD ...
Страница 56: ...56 Go to cover page 190X7 170X7 LCD AUDIO DIAGRAM 170X7 ...
Страница 58: ...58 Go to cover page 190X7 170X7 LCD Audio Board C B A 170X7 ...
Страница 59: ...Audio Board C B A 170X7 59 190X7 170X7 LCD ...
Страница 60: ...60 Go to cover page 190X7 170X7 LCD AUDIO DIAGRAM 190X7 ...
Страница 61: ...AUDIO DIAGRAM 190X7 61 190X7 170X7 LCD ...
Страница 62: ...62 Go to cover page 190X7 170X7 LCD Audio Board C B A 190X7 ...
Страница 63: ...Audio Board C B A 190X7 63 190X7 170X7 LCD ...
Страница 64: ...64 Go to cover page 190X7 170X7 LCD POWER DIAGRAM ...
Страница 65: ...POWER DIAGRAM 65 190X7 170X7 LCD ...
Страница 66: ...66 Go to cover page 190X7 170X7 LCD Power Board C B A ...
Страница 67: ...67 190X7 170X7 LCD USB DIAGRAM ...
Страница 68: ...68 Go to cover page 190X7 170X7 LCD USB Board C B A ...
Страница 69: ...USB Board C B A 69 190X7 170X7 LCD ...
Страница 70: ...70 Go to cover page 190X7 170X7 LCD CONTROL EARPHONE DIAGRAM ...
Страница 71: ...190X7 170X7 LCD Control Board C B A 71 ...
Страница 72: ...72 Go to cover page 190X7 170X7 LCD EARPHONE BOARD C B A ...