Safety Instructions,Warnings,And Notes - Philips 20PFL4122/79 Service Manual

4
TPS 1.0A LA

2.Safety Instructions,Warnings,and Notes

Index of this chapter:
2.1 Safety instructions
2.2 Warnings
2.3 Notes
2.1 Safety Instructions
Safety regulations require the following during a repair:
·
Connect set to the Mains/AC Power via an isolation
transformer(>800VA)
·
Replace safety components,indicated by the symbol ,
only by components identical to the original ones.Any
other component substitution(other than original type)may
increase risk of fire or electrical shock hazard
Safety regulations require that after a repair,the set must
be returned in its original condition.pay in particular
attention to the following points:
·
Route the wire trees correctly and fix them with the
mounted cable clamps.
·
Check the insulation of the Mains/AC power lead
for external damage.
·
Check the strain relief of the Main/AC power cord
for proper function.
·
Check the electrical DC resistance between the pins of
the Mains/AC Power plug and secondary side(only for
sets that have a Mains/AC power isolated poer supply):
1. Unplug the Mains/AC Power cord and connect a wire
between the two pins of the Mains/AC power plug.\
2.Set the Mains/AC Power switch to the ON position
(keep the Mains/AC Power cord unplugged!)
3.Measure the resistance value between the pins of the
Mains/AC Power plug and the metal shielding of the
tuner or the aerial connection on the set.The reading
should be between 4.5 Mohm and 12 Mohm.
4.Switch OFF the set,and remove the wire between " "
the two pins of the Mains/AC plug.
·
Check the cabinet for defects,to prevent touching of any inner
parts by the customer.
2.2 Warnings
·
All ICs and many other semiconductors are susceptible to
electrostatic discharges(ESD ).Careless handling during
repair can redure life drastically.Make sure that,during repair,
you are connected with same potential as the mass of the set
by wristband ith resistance .Keep components and tools also
at this same potential.Available EDS protection equipment:
-Complete kitEDS3(small tablemat,wrisband,connection box
,extension cable and earth cable)4822 310 10671.
-Wristband tester 4822 344 13999.
·
Be careful suring measurements in the high voltage section.
·
Never replace modues or other components while the unit
is switched ON . " "
·
When you align the set,use plastic rather than metal tools.This
will prevent any shurt circuits and danger of a circuit becoming
unstable.
2.3 Notes
2.3.1 General
·
Measure the voltages and waveforms with regard to the chassis
(=tuner)ground( ),or hot ground( ), depending on the tested area
of curcuitry.The voltages and waveforms shown in the diagrams
are indicative.Measure them in the Service Default Mode(see
chapter 5)with a colour bar signal and stereo sound(L:3 khz,
R:1 kHz unless statedotehrwise)and picture carrier at 475.25
Mhz for PAL,or 61.25 MHZ for NTSC(channel 3).
2.Safety Instructions,Warnings,and Notes
·
Where necessary,measure the waveforms and voltages with(
and without(
supply section both in normal operation( ) and in stand-by( ).
These values are indicated by means of the approprate symbols.
·
The semiconductors indicated in the circuit diagram and in the
parts lists,are interchangeable per position with the
semiconductors in the unit,irrespective of the type indication
on these semiconductors.
·
Manufactured under license from Dolby Laboratories. Dolby ,
" Pro Logic and the double-D symbol ,are trademarks of Dolby
laboratories.
!
2.3.2 Schematic Notes
·
All resistor values are ohms,and the value multiplier is often used
to indicate the decimal point location(e.g. 2K2 indicates 2.2 kohm).
·
Resistor values with no munltiplier may be indicated with either an
" " E or an R (e.g.220E or 220R indicates 220 ohm).
·
All capacitor values are given in micro-farads(u=x10 ),nano-
farads9n=x10 ),or pico-farads(p=x10 ).
·
Capacitor values may also use the value multiplier as the decimal
point indication(e.g. 2p2 indicates 2.2 pF).
·
An asterisk (*) indicates component usage varies.Refer to the
diversity tables for the correct values.
·
The correct component values are listed in the Spare Parts List.
Therefore,always check this list when there is amy doubt.
2.3.3 Lead-free Solder
" "
Philips CE is producing Lead-free sets (PBF) from 1.1.2005
onwards.
Idntification:The bottom line of a type gives a 14-digit serial
number.Digial 5 and 6 refer to the production year,digits 7 and
8 refer to production week( inexample below it is 2007 week14)
01
0714
Regardless of the special lead-free logo(which is not always
indicated),one must treat all sets from this date onwards
according to the rules as described below.
Due to lead-free technology some rules have to be respected
by the workshop during a repair:
)aerial signal.Measure the voltages in the power
" "
" "
-9
" "
MODEL ID.20PFL4122/93
0714
Figure 2-1 Serial number example
P
Ab
Figure 2-2 Lead-free logo
)
" "
"
-6
-12