Philips 170M4FS/00, Service Manual

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170T4
Warning and Notes
Fig.1
V
Warnings
1
2
0 V
3 ESD
4
5
6
7
8
9
10.
11.
. Safety regulations require that the unit should be returned
in its original condition and that components identical to
the original components are used. The safety components
are indicated by the symbol
.
. In order to prevent damage to ICs and transistors, all
high-voltage flash-overs must be avoided. In order to
prevent damage to the picture tube, the method shown
in Fig. 1 should be used to discharge the picture tube.
Use a high-voltage probe and a multimeter (position DC-V).
Discharge until the meter reading is
(after approximately
30 seconds).
.
All ICs and many other semiconductors are sensitive to
electrostatic discharges (ESD). Careless handling during
repair can drastically shorten their life. Make sure that
during repair you are connected by a pulse band with
resistance to the same potential as the ground of the unit.
Keep components and tools also at this same potential.
. When repairing a unit, always connect it to the AC Power
voltage via an isolating transformer.
. Be careful when taking measurements in the high-voltage
section and on the picture tube panel.
. It is recommended that saferty goggles be worn when
replacing the picture tube.
. When making adjustments,use plastic rather than metal tools.
This will prevent any short-circuit or the danger of a
circuit becoming unstable.
. Never replace modules or other components while the
unit is switched on.
. Together with the defleciton unit, the picture tube is used
as an integrated unit. Adjustment of this unit during repair
is not recommended.
After repair, the wiring should be fastened in place with
the cable clamps.
All units that are returned for service or repair must pass
the original manufactures safety tests.
Notes
The direct voltages and waveforms are average voltages.
They have been measured using the Service test software
and under the following conditions :
- Mode : 640 * 480 (31.5kHz / 60Hz)
- Signal pattern : grey scale
- Adjust brightness and contrast control for the
mechanical mid-position (click position)
The picture tube panel has printed spark gaps.
Each spark gap is connected between an electrode of the
picture tube and the Aquadag coating.
The semiconductors indicated in the circuit diagram(s)
and in the parts lists are completely interchangeable per
position with the semiconductors in the unit, irrespective
of the type indication on these semiconductors.
1.
2.
3.
(CRT ONLY)