Philips L7.2E Service Manual
1
Colour Television Chassis
L7.2E
AA
CL 86532008_004.ai
160298
ServiceManual
Table of contents Page
1 Technical specifications 2
Location of panels
2 Connection facilities 3
3 Safety instructions, Warnings 4
and Notes
4 Mechanical instructions 6
5 Repair facilities 7
Software adjustments
and Hotel mode
6 Fault finding tree 13
Block diagram, 14
Survey of testpoints 15
Diagram supply voltages survey 15
7 Electrical Diagrams and print lay-outs
Diagram PWB
Power supply diagram A1 16 17,19
Sync, Horizontal + Vertical output diagram A2 18 17,19
Tuner, IF,Video,Chroma diagram A3 20 17,19
Control diagram A4 21 17,19
Sound processing, Sound interfacediagram A5 22 17,19
CRT panel diagram B 23 23
Sound Multi-mono panel diagram C 24 25
Sound Nicam-2CS panel diagram D 26 25
8 Electrical adjustments 27
9 Circuit diagram description (new circuits) 29
10 Directions for use 32
11 List of abbreviations 36
Published by FM 9863 TV Service DepartmentPrinted in The NetherlandsCopyright reserved 1998 Philips Consumer Electronics B.V. Eindhoven, The Netherlands. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, or otherwisewithout the prior permision of Philips.Subject to modification5 4822 727 21567
12 Spareparts list 37
©
Copyright reserved 1998 Philips Consumer Electronics B.V. Eindhoven, The
Netherlands. All rights reserved. No part of this publication may be reproduced,
stored ina retrievalsystem ortransmitted, in any form or by any means, electronic, mechanical, photocopying, or otherwise without the prior permision of Philips.
Published by FM 9863 TV Service Department Printed in The Netherlands Subject to modification 5 4822 727 21567
2 L7.2E
1 Technical specifications
Mains Voltage: : 220 - 240 V AC
1 Technical specifications
: (+/- 10%)
Power consumption : 17” 50 W
: (stand by < 7 W)
: 21” 57 W
: (stand by < 7 W)
Pull in range colour sync : +/- 300 Hz
Pull in range horizontal sync : +/- 600 Hz
Pull in range vertical sync : 45 - 64.5 Hz
Location of panels
C
OR
D
MULTIMONO
NICAM,
AUDIO PANEL
MAIN
CRT
POWER SUPPLY
SYNCHRONISATION
HOR.DEFLECTION
VERT. DEFLECTION
TUNER IF
VIDEO PROCESSING
CONTROL
AUDIO SOURCE INPUT
AUDIO PROCESSING
B
A1
A2
A3
A4
A5
CL 86532008_005.ai
260398
2 Connection facilities
2 Connection facilities
3L7.2E
2.1 Cinch
IR Video
Red
EXT1
(Ext2)
L R
Audio
CL86532008_008.ai
++--
ChannelVolume
170298
4.5-7V:EXT 16:9
- Video 1Vpp/75Ω q
- Audio L(0.5Vrms ≥10kΩ) q
- Audio R(0.5Vrms ≥10kΩ) q
2.2 Head phone
- (32-600Ω≥10mW) ot
2.3 Euroconnector
1- Audio R (0.5Vrms ≤1kΩ) k
2- Audio R (0.5Vrms ≥10kΩ) j
3- Audio L (0.5Vrms ≤1kΩ) k
4- Audio v
5- Blue v
6- Audio L (0.5Vrms ≥10kΩ) j
7- Blue (0.7Vpp/75Ω)
8- CVBS-
status 0-1.3V:INT
9.5-12V:EXT 4:3 j
9- Green v
1011- Green (0.7Vpp/75Ω)
1213- Red v
14- RGB-
status v
15- Red (0.7Vpp/75Ω)
16- RGB-
status (0-0.4V:INT
1-3V:EXT/75Ω)
17- CVBS v
18- CVBS v
19- CVBS (1Vpp/75Ω) k
20- CVBS (1Vpp/75Ω) j
21- Earth
socket
4 L7.2E
3 Safety instructions, Maintenance instruction,
3 Safety instructions, Maintenance instruction, Warnings and Notes
3.1 Safety instructions for repairs
Figure 3-1
1. Safety regulations require that during a repair:
– the set should be connected to the mains via an
isolating transformer;
– safety components, indicated by the symbol (see fig.
3.1), should be replaced by components identical to
the original ones;
– when replacing the CRT, safety goggles must be worn.
2. Safety regulations require that after a repair the set must
be returned in its original condition. In particular attention
should be paid to the following points.
– As a strict precaution, we advise you to resolder the
solder joints through which the horizontal deflection
current is flowing, in particular:
• all pins of the line output transformer (LOT);
• fly-back capacitor(s);
• S-correction capacitor(s);
• line output transistor;
• pins of the connector with wires to the deflection
coil;
• other components through which the deflection
current flows.
Note: This resoldering is advised to prevent bad
connections due to metal fatigue in solder joints and is
therefore only necessary for television sets older than
2 years. The wire trees and EHT cable should be
routed correctly and fixed with the mounted cable
clamps.
– The insulation of the mains lead should be checked for
external damage.
– The mains lead strain relief should be checked for its
function in order to avoid touching the CRT, hot
components or heat sinks.
– The electrical DC resistance between the mains plug
and the secondary side should be checked (only for
sets which have a mains isolated power supply). This
check can be done as follows:
• unplugthe mains cordand connecta wirebetween
the two pins of the mains plug;
• set the mains switch to the on position (keep the
mains cord unplugged!);
• measure the resistance value between the pins of
the mains plug and the metal shielding of the tuner
or the aerial connection on the set. The reading
should be between 4.5 MW and 12 MW;
• switchoff the TV andremove the wire between the
two pins of the mains plug.
– The cabinet should be checked for defects to avoid
touching of any inner parts by the customer.
– When the set is used in circumstances with higher dust,
grease or moisture levels, for example in a kitchen, the
recommended interval is 1 year.
– The maintenance inspection contains thefollowing actions:
• Execute the above mentioned 'general repair
instruction'.
• Clean the power supply and deflection circuitry on the
chassis.
• Cleanthe picture tube panel and the neck of thepicture
tube.
3.3 Warnings
1. ESD
All ICs and many other semiconductors 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 set by a wristband with resistance. Keep
components and tools also at this same potential.
– Available ESD protection equipment:
– anti-static table mat (large 1200x650x1.25mm) 4822
466 10953
– anti-static table mat (small 600x650x1.25mm) 4822
466 10958
– anti-static wristband 4822 395 10223
– connection box (3 press stud connections, 1 M ohm)
4822 320 11307
– extension cable (2 m, 2 M ohm; to connect wristband
to connection box) 4822 320 11305
– connecting cable (3 m, 2 M ohm; to connect table mat
to connection box) 4822 320 11306
– earth cable (1 Mohm; to connect any product to mat or
connection box) 4822 320 11308
– complete kit ESD3 (combining all 6 prior products -
small table mat) 4822 310 10671
– wristband tester 4822 344 13999
2. In order to prevent damage to ICs and transistors, all highvoltage flashovers must be avoided. In order to prevent
damage to the picture tube, the method shown in Fig. 3.2
should be used to discharge the picture tube. Use a highvoltageprobe and a multimeter (positionDC-V). Discharge
until the meter reading is 0V (after approx. 30s).
3. Togetherwith the deflection unit and anymultipole unit, the
flat square picture tubes used from an integrated unit. The
deflection and the multipole units are set optimally at the
factory.Adjustmentofthisunit during repair is therefore not
recommended.
4. Be careful during measurements in the high-voltage
section and on the picture tube.
5. Never replace modules or other components while the unit
is switched on.
6. When making settings, use plastic rather than metal tools.
This will prevent any short circuits and the danger of a
circuit becoming unstable.
7. Wearsafety goggles during replacement ofthe picture tube
3.2 Maintenance instruction
It is recommended to have a maintenance inspection carried
out by a qualified service employee. The interval depends on
the usage conditions:
– When the set is used under normal circumstances, for
example in a living room, the recommended interval is 3 to
5 years.
3.4 Notes
1. The direct voltages and oscillograms should be measured
with regard to the tuner earth , or hot earth as this is called
(see fig. 3.3)
2. The direct voltages and oscillograms shown in the
diagrams are indicative and should be measured in the
Service Default Mode (see chapter 8) with a colour bar
signal and stereo sound (L:3 kHz, R:1 kHz unless stated
otherwise) and picture carrier at 475.25 MHz.
3 Safety instructions, Maintenance instruction,
3. Wherenecessary, the oscillograms and directvoltages are
measured with and without aerial signal. Voltages in the
power supply section are measured both for normal
operation and in standby . These values are indicated by
means of the appropriate symbols (see fig. 3.3).
4. The picture tube PWB has printed spark gaps. Each spark
gap is connected between an electrode of the picture tube
and the Aquadag coating.
5. The semiconductors indicated in the circuit diagram and in
the parts lists are completely interchangeable per position
with the semiconductors in the unit, irrespective of the type
indication on these semiconductors.
V
CL 26532098/042
140792
Figure 3-2
5L7.2E
tuner earth
tuner aarde
la masse du tuner
Tuner-Erde
massa del tuner
tierra del sintonizador
with aerial signal
met antenne signaal
avec signal d'antenne
mit Antennensignal
con segnale d'antenna
con la señal de antena
normal condition
normaal bedrijf
fonctionnement normal
normaler Betrieb
funzionamento normale
funcionamiento normal
massa calda
zonder antenne signaal
Figure 3-3
hot earth
hete aarde
la terre directe
heißen Erde
tierra caliente
without aerial signal
sans signal d'antenne
.ohne Antennensignal
senza segnale d'antenna
sin la señal de antena
stand by
stand by
position de veille
in Bereitschaft
modo di attesa
posición de espera
6 L7.2E
4 Mechanical instructions
For the service position of the main carrier see Fig. 4.1.
The main carrier can be removed by releasing the 2 carrier
blocking lips (1) and pulling the carrier panel backwards.
4 Mechanical instructions
1
11
B
A
CL 86532008_007.ai
160299
Figure 4-1
5 Repair facilities
7L7.2E
5 Repair facilities
5.1 Test points
The PWB boards have service printing on both sides. In the
service printing test points are included. These test points are
referring to the electrical function as mentioned below:
Test pointElectrical function
• A1,A2, etc.: Audio
• C1,C2, etc.: Control
• F1,F2, etc.: Frame drive and frame output
• L1,L2, etc.: Line drive and line output
• P1, P2,etc.: Power supply
• S1,S2- etc.: Synchronisation
• V1,V2, etc.: Video
The numbering is done in a for diagnostics logical sequence.
Example: Checking the power supply, start with test point P1,
P2 etc.).
5.2 Service mode
The service mode is split into two parts:
– Service Default Mode (SDM).
– Service Alignment Mode (SAM).
– For Multi-Europe setsPAL-BG
– For Multi-France setsSECAM-L
Tuning:
– For sets with VST tuner: Programme number 1is selected .
Further settings:
– The automatic switch off (no IDENT) timer and the sleep
timer will be ignored.
– The child lock will be disabled.
– If the TV set was in hotel mode, this mode is disabled as
long as the TV is in SDM or SAM mode.
– Brightness, saturation, sharpness, contrast and balance
are initialised on 50% level.
– The volume is set to 25% level.
– The TV set is normally controllable.
– All displayed text in SDM and SAM menu are in English.
5.4 SDM (Service Default Mode)
5.4.1 SDM menu
Below in Fig.6.1 an example of the SDM menu is shown.
Between clamps a short explanation of each item is added.
5.2.1 Entering and leaving SDM and SAM
1. Entering SDM
• To entry the SDM , there are two possibilities:
– Via the "DEFAULT" button on the DST (Dealer
Service Tool)
– Via short circuiting the service pins 0025 and 0024
(mass), while switching on the set via the mains
switch. For 0025 and 0024 see Diagram A4 and
the PWB drawing of the main panel.
• Inthe SDM mode aS (in green) and the SDM menu(in
red) is displayed.(see Fig.6.1).
2. Entering SAM
• To entry the SAM , there are two possibilities.
– Viathe "ALIGN" button on the DST (Dealer Service
Tool)
– Via short circuiting the Service pins M28 and M29
(mass), while switching on the set via the mains
switch. For M28 and M29 see Diagram A4 and the
PWB drawing of the main panel.
• In the SAM mode a S (in green) and the SAM main
menu (in red) is displayed.(see Fig.6.2).
Remark: After the set is in the SDM or SAM mode the short
circuit can be removed.
001E 2.17.6 S
(life timer) (software
indication)
AS ON
(option abbreviation) (option status)
ERR 0 0 0 0 0
(error) (error buffer)
OPT 36C8 B805 2401
(option) (12 digit option
code)
Fig.6.1
(service mode
indication)
5.2.2 Leaving SDM or SAM
To leave the SDM or SAM mode , push the stand-by button on
the remote control
Remark:After switching off and on bythemains switch , the set
remains in the SDM or SAM mode.
5.3 Initial states
The initial state after switching on in the SDM or SAM mode is:
System:
Below a more detailed information of each item is given
5.4.2 Life timer
The indication is in hexadecimal notation. Each hour the set is
switched on (not standby) the number is incremented by 1.
Also each time the set is switched on the number is
incremented by 1.
8 L7.2E
5 Repair facilities
5.4.3 Software indication number.
For each software change this number will be changed.
5.4.4 Service mode indication.
The S indicates that the set is in SDM or SAM mode.
5.4.5 ERROR and ERROR buffer
(ERR refers to the "ERROR BUFFER")
00000 represent the contents of the so called "ERROR
BUFFER". This buffer consist of 5 digits. In each digit an
ERROR code can be displayed. Thelast five errors, are stored
in the EEPROM, and are shown in this buffer. An error will be
added to the buffer if this error differs from the last error in the
buffer. The last detected error is displayed on the most left
digit.
Example: Suppose the display shows: 3 4 1 3 1. This means
the last found error is error code 3; the last found error but one
is error code 4, etc.
Remark: The ERROR BUFFER is erased when the set is
switched from SDM or SAM in stand by , or via code 99 via
DST.(Dealer service Tool).
5.4.7 Option abbreviation and Option status.
To select another option abbreviation use the MENU UP/
DOWN buttons and to change the status use the MENU LEFT/
RIGHT buttons.
Elucidation:
With above items the option statuses stored in the EEPROM
can be changed.
This is necessary if the EEPROM is replaced by a fresh
EEPROM, because a fresh EEPROM is initial loaded with
default options and statuses by the microcomputer. The
options stored in the factory can differ per type and stroke
number. Therefore it is necessary to load the EEPROM with
the correct statuses These options with statuses are indicated
on a sticker glued on the CRT. For an example of the sticker
see table 6.1 (this table is valid for 21PT1663/00).
Table 6.1
Option abbreviation Status
AT ON
AV ON
The following error codes have been defined:
Error code Error description Possible defective
omponent
0 No error
1 Internal RAM error
of æC
2 General I2C error
3 EEPROM
Configuration error
(Checksum error)
4 I2C error audio
processor
5 I2C error TV
processor
6 EEPROM error ST24C04
7 I2C error PLL tuner PLL tuner
8 POR bit high (43-
IC7600)
IC7600
Set not correct
configured
MSP3410 on
NICAM panel
TDA8373/74
BA ON
BL ON
CO OFF
GM ON
HO ON
MT PH
PG ON
PR 99
SA ON
SB IN
SP ON
SS ON
SU ON
SY EW
TR ON
UH OFF
VI OFF
5.4.6 ERROR code indication via blinking stand by LED
The ERROR codes 2, 5 and 8 are also indicated via blinking of
the stand by LED. This is important if no OSD function or
picture is available.
The method is to show LED blinks as many as the error code.
Example: Error code 5 will result in five blinks ( 0.25 seconds
ON and 0.25 seconds OFF).
After this sequence the LED will be OFF for 3 seconds.
XT ON
(Table only valid for 21PT1663/00)
Loading a fresh EEPROM
– Switch on the TV via the power switch.
– Audio mute the TV (to get no big noise).
– Change the option statuses as indicated on the sticker on
theCRT.
– Put TV in stand by via the remote control.
– Switch on the TV again via the remote control.
5 Repair facilities
9L7.2E
– Switch OFF the TV via the power switch
– Switch on the TV again via the power switch.
In table 2 all the possible option abbreviation with full option
name and possible statuses for "Europe" sets are listed. The
status can be "ON", "OFF" or can have another indication.
Table 2 : Options
Option abbr Option full name Status possibilities
AT Auto tuning system ON/OFF
AV AVL ON/OFF
BA Bass ON/OFF
BL Balance ON/OFF
CO Clock In Menu ON/OFF
GM Game mode ON/OFF
HO Hotel mode ON/OFF
MT Menu type PH = Philips
5.4.8 OPTION code
OPT is the abbreviation of OPTION, this abbreviation refers to
the following 12 digit hexadecimal option codes (36C8 B805
2401)
The option code can not be selected. It only give a quick
indication in hexadecimal form of the options settings of the
relevant set.
5.5 SAM (Service Alignment Mode)
Via the SAM, service software alignments can be executed.
When entering SAM a main menu is displayed Via the main
menu sub menus can be selected.
5.5.1 SAM main menu (see Fig. 6.2)
In the main menu the items of the basic software alignments
are indicated.
Theitems can be selected withthe UP(+)/DOWN(-) arrow keys
on the remote control. Entry into the sub menus is executed
with the VOL.(+)/VOL.(-) arrow keys.
SAM MAIN MENU
NB = National brand
MV = Magnavox
PG Program guide ON/OFF
PR Presets 99
59
79
SA Spatial ON/OFF
SB Sound Board IN = ITT NICAM
IT = ITT 2CS
MA = MONO ALL
MM = Multi Mono
SP Smart picture ON/OFF
SS Smart Sound Full ON/OFF
SU Surf ON/OFF
SY System Cluster EW = Europe West
EE = Europe East
EM = Europe
Manual
SS = Single System
TR Treble ON/OFF
UH UHF only ON/OFF
VI Virgin Mode ON/OFF
XT EXT 2 Available ON/OFF
S
AKB ON
TUN.FOA ON
TUN.FOB ON
EXT.FOA ON
EXT.FOB OFF
TUNER >
WHITE TONE >
GEOMETRY >
Fig.6.2
Below each item is explained.
5.5.2 AKB (Auto Kine Biasing)
With the option AKB the "black current loop" can be enabled
or disabled
ON =enabled, OFF = disabled.
5.5.3 TUNER Speed setting.
With the items TUN.FAO and TUN.FOB the speed ( time
constant) for internal signals is set. The speed can be set to
normal, slow or fast.
Table 3: Options for Tuner Speed settings
10 L7.2E
5 Repair facilities
5.5.6 White tone
TUN.FOA TUN.FOB Speed
OFF OFF Normal
OFF ON Slow
ON X Fast
5.5.4 EXTERNAL A/V Speed setting
With the items EXT.FAO and EXT.FOB the speed ( time
constant) for external signals is set. The speed can be set
normal, slow and fast.
Table 4: Options for External AV Speed settings
EXT.FOA EXT.FOB Speed
OFF OFF Normal
OFF ON Slow
ON X Fast
5.5.5 Tuner
Below an example of the sub menu Tuner is shown.
Below an example of the white tone sub menu and the derived
"WARM", "COOL" and "NORMAL" sub menus are given. With
these menus the WARM, COOL and NORMAL colour
temperatures can be changed.
MAIN WHITE TONE MENU
S
WARM <
COOL <
NORMAL <
WARM TEMPERATURE SUB MENU
WARM S
RED 39
Tuner S
AGC 23
F-PLL 3
IF PLL L' 0
AFW 240 KHz
AFA 0
AFB 1
Item AGC:
For the setting of the item AGC see RF AGC adjustment
paragraph 8.1.4 of chapter 8.
Item IF-PLL, IF-PLL L ACCENT, AFW, AFA and AFB,
When the main signal processor IC TDA8373/74 is changed,
the IF-PLL and IF-PLL L ACCENT need to be realigned
GREEN 39
BLUE 25
COOL TEMPERATURE SUB MENU
COOL S
RED 39
GREEN 39
BLUE 25
NORMAL TEMPERATURE SUB MENU
NORMAL S
RED 39
GREEN 39
BLUE 25
Forthe settings of IF-PLL, IF-PLL L ACCENTandAFW see the
picture demodulator adjustments paragraph 8.1.5 of chapter 8.
Remark: AFA and AFB are adjusting indicators and therefore
not selectable.
Remark:
Only one of the 3 items (RED, GREEN or BLUE) will be
displayedonthescreen.Via"scrollingwiththeUP/DOWN keys
the items can be changed.
The item's red, green or blue can be changed by first pressing
the control left/right keys to highlight the desired setting. With
the desired setting high lighted, the user can increment or
decrement the setting by using the control up/down key. All
5 Repair facilities
11L7.2E
changed data are stored into the EEPROM after returning to
the SAM main menu via the OK key.
The initial default value for all setting is 37.
The factory settings of the colour temperatures are:
WARM; R = 45, G = 32, B = 26
NORMAL; R = 37, G = X, B = Y
COOL; R = 37, G = 32, B = 31
Remark: In NORMAL position the values X (G) and Y (B) are
adjusted for 8500K colour temperature.
5.5.7 GEOMETRY
The geometry menu contains the following information:
S
HSH 25
VSL 32
VAM 23
– All software is suspended till the DST mode is left.
– The dealer mode status is left if the stand-by command is
received
5.7 Hotel-mode
Entering the hotel-mode :
– Select channel 38
– Push the menu button on the local keyboard (vol. + & vol.
- ) and the OSD-button of the RC simultaneously for 3
seconds.
– The screen shows the "HOTEL MODE SUB MENU "ON".
Via this menu the wanted blanked channels can be
selected.
Leaving the hotel mode :
– Same as entering the hotel mode.
– The screen shows the "HOTEL MODE SUB MENU "OFF".
Remarks:
– In the HOTEL mode the Installation menu cannot be
entered.
– When entering the hotel mode the maximum volume will
be the current value.
– The set will always switch to a selectable channel when
set is switched on.
SC 13
VSH 27
Uponenter into the picture geometry menu, thefirstitem will be
highlighted.
The value can be incremented or decremented by pressing the
control right or left key.
Therestof the parameters can be scrolled through by usingthe
control up/down keys.
All changed data will be stored into the EEPROM after
returning to the service main menu via the OK key.
Abbreviation explanation
– HSH - Horizontal shift
– VSL - Vertical linearity
– VAM - Vertical amplitude
– SC - S-correction
– VSH - Vertical shift
5.6 Use of Dealer Service Tool (DST)
With the SDM, under mentioned extra service features can be
executed
HOTEL MODE SUB MENU "ON"
38 HOTEL ON
EXIT >
HOTEL CHANNEL 38
HOTEL MODE SUB MENU " OFF "
38 HOTEL OFF
– Direct entering SDM via the "DEFAULT" button on the
DST.
– Direct entering SAM via the "ALIGN" button on the DST.
– Incase of no (OSD)picture theerror buffercan be readout
using the "BLINKING LED"procedure (see also paragraph
6.7) by pressing the "DIAGNOSE" button on the DST.
Remark:
– Entry of the SDM and SAM via the DST is possible in all
states, except from stand-by.
Remark: The Hotel mode can only be activated if the Hotel
mode option status (HO=ON), see table 2.
12 L7.2E
5 Repair facilities
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