Copyright 2006 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 otherwise without the prior permission of Philips.
Control Panel (26” & 32”)(E) 145146
Control Panel (37” & 42”)(E) 145147
Front IR / LED Panel (26”)(J) 148148
Front IR / LED Panel (32”, 37”, & 42”)(J) 149149
Standby/Audio Panel: Connections(SA1) 150153-155
Standby/Audio Panel: Standby (32”& Up) (SA2) 151153-155
Standby/Audio Panel: Audio (32”& Up)(SA3) 152153-155
8. Alignments157
9. Circuit Descriptions, Abbreviation List, and IC Data
Sheets163
Abbreviation List165
IC Data Sheets168
10. Spare Parts List178
11. Revision List189
Published by WS 0665 BG CD Customer ServicePrinted in the NetherlandsSubject to modificationEN 3122 785 16291
EN 2EL1.1U AA1.
Technical Specifications, Connections, and Chassis Overview
1.Technical Specifications, Connections, and Chassis Overview
Index of this chapter:
1.1 Technical Specifications
1.2 Connection Overview
1.3 Chassis Overview
Notes:
•Some models in this chassis range have a different
mechanical construction. The information given here is
therefore model specific.
•Figures below can deviate slightly from the actual situation,
due to the different set executions.
•Specifications are indicative (subject to change).
1.1Technical Specifications
1.1.1Vision
Display type: LCD
Screen size: 26” (67 cm), 16:9
Resolution (HxV pixels): 1366(*3)x768p
Min. contrast ratio: 600:1
Min. light output (cd/m
2
): 500
Max. response time (ms): 12
Viewing angle (HxV degrees): 176x176
Tuning system: PLL
TV Color systems: ATSC, NTSC
Video playback: NTSC
Cable: Unscrambled digital
Tuner bands: VHF, UHF, S, Hyper
Supported video formats: 640x480i-1fH
Note: The following connector color abbreviations are used
(acc. to DIN/IEC 757): Bk= Black, Bu= Blue, Gn= Green, Gy=
Grey, Rd= Red, Wh= White, and Ye= Yellow.
1.2.1Side Connections
1.1.2Sound
Sound systems: AV Stereo
Maximum power (W
): 2 x 15
RMS
1.1.3Multimedia
Supported file formats: JPEG
USB input: USB1.1
1.1.4Miscellaneous
Power supply:
- Mains voltage (V
): 100 - 240 (26”)
AC
- Mains frequency (Hz): 50/60 (26”)
Ambient conditions:
- Temperature range (°C): +5 to +40
:BTSC
: Dolby Digital (AC3)
: 2 x 8 (26” only)
:MP3
: Slideshow (.alb)
: 110 - 120 (32”, 37”,
42”)
: 60 (32”, 37”, 42”)
G_16290_067.eps
300106
Figure 1-1 Side I/O connections
Mini Jack: Audio Headphone - Out
Bk -Headphone 32 - 600 ohm / 10 mW ot
Cinch: Video CVBS - In, Audio - In
Ye -Video CVBS 1 V
Wh -Audio L 0.5 V
Rd - Audio R 0.5 V
/ 75 ohm jq
PP
/ 10 kohm jq
RMS
/ 10 kohm jq
RMS
S-Video (Hosiden): Video Y/C - In
1-Ground Y Gnd H
2-Ground C Gnd H
3-Video Y 1 V
4-Video C 0.3 V
/ 75 ohm j
PP
P / 75 ohm j
PP
Technical Specifications, Connections, and Chassis Overview
EN 3EL1.1U AA1.
USB1.1
1234
E_06532_022.eps
300904
Figure 1-2 USB (type A)
1-+5V k
2-Data (-) jk
3-Data (+) jk
4-Ground Gnd H
1.2.2Rear Connections
Figure 1-3 Rear connections
AV3 S-Video (Hosiden): Video Y/C - In
1-Ground Y Gnd H
2-Ground C Gnd H
3-Video Y 1 V
4-Video C 0.3 V
/ 75 ohm j
PP
P / 75 ohm j
PP
G_16290_068.eps
300106
HDMI 1: Digital Video, Digital Audio - In
19
182
1
E_06532_017.eps
250505
Figure 1-4 HDMI (type A) connector
1-D2+ Data channel j
2-Shield Gnd H
3-D2- Data channel j
4-D1+ Data channel j
5-Shield Gnd H
6-D1- Data channel j
7-D0+ Data channel j
8-Shield Gnd H
9-D0- Data channel j
10 - CLK+ Data channel j
11 - Shield Gnd H
12 - CLK- Data channel j
13 - n.c.
14 - n.c.
15 - DDC_SCL DDC clock j
16 - DDC_SDA DDC data jk
17 - Ground Gnd H
18 - +5V j
19 - HPD Hot Plug Detect j
20 - Ground Gnd H
Aerial - In
--F-type (US) Coax, 75 ohm D
AV3 Cinch: Video CVBS - In
Ye -Video CVBS 1 V
/ 75 ohm jq
PP
AV3 Cinch: Audio - In
Wh -Audio L 0.5 V
Rd - Audio R 0.5 V
RMS
RMS
Cinch: S/PDIF - Out
Bk -Coaxial 0.4 - 0.6V
AV2 Cinch: Video YPbPr - In
Gn - Video Y 1 V
Bu -Video Pb 0.7 V
Rd - Video Pr 0.7 V
/ 75 ohm jq
PP
PP
PP
AV2 Cinch: Video CVBS - In
Ye -Video CVBS 1 V
/ 75 ohm jq
PP
AV2 Cinch: Audio - In
Wh -Audio L 0.5 V
Rd - Audio R 0.5 V
RMS
RMS
AV1 Cinch: Video YPbPr - In
Gn - Video Y 1 V
Bu -Video Pb 0.7 V
Rd - Video Pr 0.7 V
/ 75 ohm jq
PP
PP
PP
AV1 Cinch: Video CVBS - In
Ye -Video CVBS 1 V
/ 75 ohm jq
PP
/ 10 kohm jq
/ 10 kohm jq
/ 75 ohm kq
PP
/ 75 ohm jq
/ 75 ohm jq
/ 10 kohm jq
/ 10 kohm jq
/ 75 ohm jq
/ 75 ohm jq
AV1 Cinch: Audio - In
Wh -Audio L 0.5 V
Rd - Audio R 0.5 V
/ 10 kohm jq
RMS
/ 10 kohm jq
RMS
EN 4EL1.1U AA1.
1.3Chassis Overview
Technical Specifications, Connections, and Chassis Overview
LCD SUPPLY
A
PANEL
SMALL SIGNAL
B
BOARD
Figure 1-5 PWB/CBA locations (26-inch model)
CONTROL
BOARD
SIDE I/O
PANEL
IR / LED
PANEL
E
D
J
LCD SUPPLY
A
PANEL
SMALL SIGNAL
B
BOARD
Figure 1-6 PWB/CBA locations (32-inch model)
STANDBY /
AUDIO PANEL
SIDE I/O
PANEL
CONTROL
BOARD
LED PANEL
G_16290_069.eps
SA
D
E
J
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SMALL SIGNAL
B
BOARD
Technical Specifications, Connections, and Chassis Overview
LCD SUPPLY
PANEL
EN 5EL1.1U AA1.
A
CONTROL
E
BOARD
STANDBY / AUDIO
SA
PANEL
Figure 1-7 PWB/CBA locations (37-inch model)
G_16290_094.eps
030206
SIDE I/O
PANEL
IR / LED
PANEL
LCD SUPPLY
PANEL
D
J
A
CONTROL
E
BOARD
SMALL SIGNAL
B
BOARD
Figure 1-8 PWB/CBA locations (42-inch model)
G_16290_095.eps
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SIDE I/O
PANEL
IR / LED
PANEL
D
J
EN 6EL1.1U AA2.
Safety Instructions, Warnings, and Notes
2.Safety Instructions, Warnings, and Notes
Index of this chapter:
2.1 Safety Instructions
2.2 Warnings
2.3 Notes
2.1Safety Instructions
Safety regulations require that during a repair:
•Connect the set to the Mains/AC Power via an isolation
transformer (> 800 VA).
•Replace safety components, indicated by the symbol h,
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 Mains/AC Power cord for
proper function.
•Check the electrical DC resistance between the Mains/AC
Power plug and the secondary side (only for sets which
have a Mains/AC Power isolated power 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 Power plug.
•Check the cabinet for defects, to avoid touching of any
inner parts by the customer.
2.2Warnings
•All ICs and many other semiconductors are susceptible to
electrostatic discharges (ESD w). Careless handling
during repair can reduce life drastically. Make sure that,
during repair, 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:
– Complete kit ESD3 (small tablemat, wristband,
connection box, extension cable and earth cable) 4822
310 10671.
– Wristband tester 4822 344 13999.
•Be careful during measurements in the high voltage
section.
•Never replace modules or other components while the unit
is switched "on".
•When you align the set, use plastic rather than metal tools.
This will prevent any short circuits and the danger of a
circuit becoming unstable.
2.3Notes
2.3.1General
•Measure the voltages and waveforms with regard to the
chassis (= tuner) ground (H), or hot ground (I), depending
on the tested area of circuitry. The voltages and waveforms
shown in the diagrams are indicative. Measure them in the
Service Default Mode (see chapter 5) with a color bar
signal and stereo sound (L: 3 kHz, R: 1 kHz unless stated
otherwise) and picture carrier at 475.25 MHz for PAL, or
61.25 MHz for NTSC (channel 3).
•Where necessary, measure the waveforms and voltages
with (D) and without (E) aerial signal. Measure the
voltages in the power supply section both in normal
operation (G) and in stand-by (F). These values are
indicated by means of the appropriate 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.
2.3.2Schematic Notes
•All resistor values are in 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 multiplier 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 (µ= x10
nano-farads (n= 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 any
doubt.
2.3.3Rework on BGA (Ball Grid Array) ICs
General
Although (LF)BGA assembly yields are very high, there may
still be a requirement for component rework. By rework, we
mean the process of removing the component from the PWB
and replacing it with a new component. If an (LF)BGA is
removed from a PWB, the solder balls of the component are
deformed drastically so the removed (LF)BGA has to be
discarded.
Device Removal
As is the case with any component that, it is essential when
removing an (LF)BGA, the board, tracks, solder lands, or
surrounding components are not damaged. To remove an
(LF)BGA, the board must be uniformly heated to a temperature
close to the reflow soldering temperature. A uniform
temperature reduces the chance of warping the PWB.
To do this, we recommend that the board is heated until it is
certain that all the joints are molten. Then carefully pull the
component off the board with a vacuum nozzle. For the
appropriate temperature profiles, see the IC data sheet.
Area Preparation
When the component has been removed, the vacant IC area
must be cleaned before replacing the (LF)BGA.
Removing an IC often leaves varying amounts of solder on the
mounting lands. This excessive solder can be removed with
either a solder sucker or solder wick. The remaining flux can be
removed with a brush and cleaning agent.
After the board is properly cleaned and inspected, apply flux on
the solder lands and on the connection balls of the (LF)BGA.
Note: Do not apply solder paste, as this has shown to result in
problems during re-soldering.
-9
), or pico-farads (p= x10
-12
-6
),
).
Safety Instructions, Warnings, and Notes
EN 7EL1.1U AA2.
Device Replacement
The last step in the repair process is to solder the new
component on the board. Ideally, the (LF)BGA should be
aligned under a microscope or magnifying glass. If this is not
possible, try to align the (LF)BGA with any board markers.
So as not to damage neighboring components, it may be
necessary to reduce some temperatures and times.
More Information
For more information on how to handle BGA devices, visit this
URL: www.atyourservice.ce.philips.com (needs subscription,
not available for all regions). After login, select “Magazine”,
then go to “Repair Downloads”. Here you will find Information
on how to deal with BGA-ICs.
2.3.4Lead Free Solder
Philips CE is producing lead-free sets (PBF) from 1.1.2005
onwards.
Identification: The bottom line of a type plate gives a 14-digit
serial number. Digits 5 and 6 refer to the production year, digits
7 and 8 refer to production week (in example below it is 1991
week 18).
E_06532_024.eps
230205
avoid mixed regimes. If not to avoid, clean carefully the
solder-joint from old tin and re-solder with new tin.
•Use only original spare-parts listed in the Service-Manuals.
Not listed standard material (commodities) has to be
purchased at external companies.
•Special information for lead-free BGA ICs: these ICs will be
delivered in so-called "dry-packaging" to protect the IC
against moisture. This packaging may only be opened
short before it is used (soldered). Otherwise the body of the
IC gets "wet" inside and during the heating time the
structure of the IC will be destroyed due to high (steam)pressure inside the body. If the packaging was opened
before usage, the IC has to be heated up for some hours
(around 90°C) for drying (think of ESD-protection!).
Do not re-use BGAs at all!
•For sets produced before 1.1.2005, containing leaded
soldering tin and components, all needed spare parts will
be available till the end of the service period. For the repair
of such sets nothing changes.
In case of doubt whether the board is lead-free or not (or with
mixed technologies), you can use the following method:
•Always use the highest temperature to solder, when using
SAC305 (see also instructions below).
•De-solder thoroughly (clean solder joints to avoid mix of
two alloys).
Caution: For BGA-ICs, you must use the correct temperatureprofile, which is coupled to the 12NC. For an overview of these
profiles, visit the website www.atyourservice.ce.philips.com
(needs subscription, but is not available for all regions)
You will find this and more technical information within the
"Magazine", chapter "Repair Downloads".
For additional questions please contact your local repair help
desk.
Figure 2-1 Serial number example
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.
P
b
Figure 2-2 Lead-free logo
Due to lead-free technology some rules have to be respected
by the workshop during a repair:
•Use only lead-free soldering tin Philips SAC305 with order
code 0622 149 00106. If lead-free solder paste is required,
please contact the manufacturer of your soldering
equipment. In general, use of solder paste within
workshops should be avoided because paste is not easy to
store and to handle.
•Use only adequate solder tools applicable for lead-free
soldering tin. The solder tool must be able
– To reach at least a solder-tip temperature of 400°C.
– To stabilize the adjusted temperature at the solder-tip.
– To exchange solder-tips for different applications.
•Adjust your solder tool so that a temperature around 360°C
- 380°C is reached and stabilized at the solder joint.
Heating time of the solder-joint should not exceed ~ 4 sec.
Avoid temperatures above 400°C, otherwise wear-out of
tips will rise drastically and flux-fluid will be destroyed. To
avoid wear-out of tips, switch “off” unused equipment or
reduce heat.
•Mix of lead-free soldering tin/parts with leaded soldering
tin/parts is possible but PHILIPS recommends strongly to
2.3.5Practical Service Precautions
•It makes sense to avoid exposure to electrical shock.
While some sources are expected to have a possible
dangerous impact, others of quite high potential are of
limited current and are sometimes held in less regard.
•Always respect voltages. While some may not be
dangerous in themselves, they can cause unexpected
reactions that are best avoided. Before reaching into a
powered TV set, it is best to test the high voltage insulation.
It is easy to do, and is a good service precaution.
EN 8EL1.1U AA3.
3.Directions for Use
Directions for Use
You can download this information from the following websites:
http://www.philips.com/support
http://www.p4c.philips.com
3.1Ho tel Mode
3.1.1Introduction
As the 26” version of the EL1.1U AA chassis is equipped with
Hotel Mode, here is a brief explanation on how to activate and
configure it.
3.1.2The Benefits of Hotel Mode
This TV is specially designed to operate in Hotel Mode. Hotel
Mode offers the following benefits:
•Access to the user menu can be blocked. This prevents
users (e.g. guests) from deleting or changing channel
settings and/or modifying picture and sound settings.
Picture and sound can only be controlled via preprogrammed Smart Settings and buttons on the remote
control. This ensures that TVs are always set up correctly.
•A switch-on volume and channel can be selected. After
switching on, the TV will always start on the specified
channel and volume level.
•The maximum volume can be limited in order to prevent
disturbance.
•Channels can be blanked.
•The television keys VOLUME +/-, CHANNEL +/- and
MENU can be blocked.
•Screen information can be suppressed.
3.1.3Activating the Hotel Mode Setup Menu
1. Switch on the television and select a TV channel.
2. On the remote control, press keys: [3, 1, 9, 7, 5, 3, MUTE]
3. The HOTEL MODE SETUP MENU becomes visible.
4. Use the cursor keys to select and change any of the
functions.
5. Select "STORE" and press [CURSOR RIGHT] to save the
settings and exit Hotel Mode setup. Press [MENU] to exit
without saving.
CHANNEL BLANK
Selection Description
YESThe current channel is blanked.
NOThe current channel is not blanked (normal
visible; DEFAULT value)
CHANNEL BLANK can be set for every channel. Use [CH+ /
CH-] to visit all the channels and set the desired status per
channel. The channel number is visible in the top left corner.
KEYBOARD LOCK
Selection Description
YESThe television keys VOLUME +/-, CHANNEL +/-
and MENU are blocked.
NOThe television keys VOLUME +/-, CHANNEL +/-
and MENU function normally.
MAX VOLUME
Selection Description
0 .. 99The TV Volume will not exceed the selected
volume level.
ON VOLUME
Selection Description
0 .. 99When the user switches the TV ON, it will play at
the specified volume level. Note: "ON VOLUME"
cannot exceed the MAXIMUM VOLUME level.
OSD DISPLAY
Selection Description
YESNormal screen information is displayed (example:
channel information).
NOOn Screen Display can be suppressed (except for
some VGA input, if present).
MONITOR OUT
Selection Description
YESEnables Audio & Video output from the TV.
NODisables Audio & Video output from TV
3.1.4Hotel Mode Functions
This section describes the functionality of the menu items in the
Hotel Mode Setup menu.
HOTEL MODE
Selection Description
YESHotel Mode is ON:
- The user menu is blocked.
- The volume level is limited (to the volume level
when Hotel Mode Setup was entered).
- All settings of the Hotel Mode Setup menu are in
effect.
NOHotel Mode is OFF:
- The TV operates as a normal consumer TV.
INSTALL Allows the TV Set to auto-install without PSIP
activated (if PSIP is set to NO)
ON CHANNEL
Selection Description
0 .. 99,
EXT1,2,3
When the user switches the TV ON, it will tune to
the specified channel or External AV.
POWER ON
Selection Description
FORCED Sets the TV immediately to ON after the mains
power is connected.
STANDBY Sets the TV to standby mode after the mains
power is connected.
PSIP
Selection Description
YESEnables recognition of PSIP settings (during
installation).
NODisables recognition of PSIP settings (during
installation).
4.Mechanical Instructions
Mechanical Instructions
EN 9EL1.1U AA4.
Index of this chapter:
4.1 Cable Dressing
4.2 Service Positions
4.3 Assy/Panel Removal
4.4 Set Re-assembly
4.1Cable Dressing
Notes:
•Several models in this chassis range have a different
mechanical construction, the instructions given in this
chapter are therefore very model specific.
•Figures below can deviate slightly from the actual situation,
due to the different set executions.
•Follow the disassemble instructions in described order.
Figure 4-1 Cable dressing (26-inch model)
G_16290_089.eps
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EN 10EL1.1U AA4.
Mechanical Instructions
Figure 4-2 Cable dressing (32-inch model)
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Figure 4-3 Cable dressing (37-inch model)
G_16290_091.eps
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Mechanical Instructions
EN 11EL1.1U AA4.
Figure 4-4 Cable dressing (42-inch model)
4.2Service Positions
For easy servicing of this set, there are a few possibilities
created:
•Foam bars (created for Service).
•Aluminium service stands (created for Service).
4.2.1Foam Bars
E_06532_018.eps
Figure 4-5 Foam bars
The foam bars (order code 3122 785 90580 for two pieces) can
be used for all types and sizes of Flat TVs. By laying the TV
face down on the (ESD protective) foam bars, a stable situation
is created to perform measurements and alignments.
By placing a mirror under the TV, you can monitor the screen.
170504
G_16290_092.eps
4.2.2Aluminium Stands
E_06532_019.eps
170504
Figure 4-6 Aluminium stands (drawing of MkI)
The new MkII aluminium stands (not on drawing) with order
code 3122 785 90690, can also be used to do measurements,
alignments, and duration tests. The stands can be
(dis)mounted quick and easy by means of sliding them in/out
the "mushrooms". The new stands are backwards compatible
with the earlier models.
Important: For (older) FTV sets without these "mushrooms", it
is obligatory to use the provided screws, otherwise it is possible
to damage the monitor inside!.
030206
EN 12EL1.1U AA4.
s
6
Mechanical Instructions
4.3Assy/Panel Removal
4.3.1Rear Cover
Warning: Disconnect the mains power cord before you remove
the rear cover.
1. Place the TV set upside down on a table top, using the
foam bars (see part "Foam Bars").
Caution: do not put pressure on the display, but let the
monitor lean on the speakers or the Front cover.
2. Remove all screws that secure the rear cover.
3. Lift the rear cover from the cabinet cautiously. Make sure
that wires and other internal components are not damaged
during cover removal.
4.3.2Keyboard Control Panel
1. Remove the screws [1] that secure the panel.
2. Disconnect the cable [2] from the panel.
3. Remove the panel.
When defective, replace the whole unit.
1
2
3
4
4.3.6Stand-by Power Supply/Audio Amplifier Panel (if present)
1. Disconnect all cables [1] from the panel.
2. Remove the fixation screws [2] from the panel. The
positioning might differ from the locations as indicated in
Figure “Stand-by/Audio panel”.
3. Take the panel out of its brackets (it hinges at the bottom
side).
2
1
2
F_15420_042.eps
070605
Figure 4-8 Stand-by/Audio panel
4.3.7LCD Supply Panel
1. Disconnect all cables [1] from the panel.
2. Remove the fixation screws [2] from the panel.
6
3. Take the panel out of its brackets (it hinges on the right
side).
5
1
7
G_16290_071.eps
8
310106
Figure 4-7 Keyboard Control panel, Side I/O panel and LED panel.
4.3.3Side I/O Panel
1. Disconnect the cables [3][4][5] from the panel.
2. Remove the panel from its brackets [6].
When defective, replace the whole unit.
4.3.4LED Panel
1. Disconnect the cable [7] from the panel.
2. Remove the panel from its bracket [8].
When defective, replace the whole unit.
26 and 32-inch models
2
2
2
2
2
1
2
2
1
2
Figure 4-9 LCD supply panel(s)
37 and 42-inch models
1
1
2
1
1
G_16290_088.ep
03020
4.3.5Speakers
After removal of the rear cover, you can access the speakers.
Mechanical Instructions
EN 13EL1.1U AA4.
4.3.8Small Signal Board (SSB)
1
1 11
1
1
Figure 4-10 SSB bottom shielding
1. Remove the connector fixation screws [1] at the connector
plate (bottom side, see Figure “SSB bottom shielding”).
2. Unplug the LVDS connector [1] on the SSB (SSB top side,
see Figure “SSB top view”). Be careful as it is very fragile.
3. Unplug all other cables on the SSB.
4. Remove the mounting screws [2] that hold the SSB, and lift
the panel from the set.
1
G_16290_072.eps
310106
Take care not to damage the fragile LVDS cable.
Ensure that the conducting tape [1] at both sides of the
panel is secured for re-assembly (see Figure “Conducting
tape”).
10. After removal of the metal frame, you can lift the LCD panel
from the front cabinet.
1
G_16290_074.eps
310106
Figure 4-12 LVDS connector
2
Figure 4-11 SSB top view
4.3.9LCD Panel
To remove the LCD-panel, carry out the following steps:
1. Disconnect the cables from the “L” and the “R”
loudspeakers.
2. Important: Unplug the LVDS connector [1] on the LCD
panel (see Figure “LVDS connector”). Be careful, as this is
a very fragile connector!
3. Take the Side I/O panel and the LED panel out of its
brackets (see Figure “Keyboard Control panel, Side I/O
panel and LED panel” at the beginning of this chapter).
4. Unplug the cable from the Keyboard Control panel and
remove this cable from its cable clamp (see Figure
“Keyboard Control panel, Side I/O panel and LED panel” at
the beginning of this chapter).
5. Unplug the LCD backlight connectors [2] of the LCD panel
(see Figure “Fixation screws and LCD backlight
connectors”).
6. Remove the Stand-by Power Supply/Audio Amplifier Panel
as described previously in this chapter, because of a
hidden screw.
7. Remove the panel fixation screws and at the same time
disconnect the remaining cable connected to the Side I/O
panel (see Figure “Fixation screws and LCD backlight
connectors”).
8. Remove the LCD panel fixation screws [1]. See Figure
“Location of LCD panel fixation screws”.
9. Lift the metal frame (together with all PWBs) from the LCD
panel.
G_16290_073.eps
310106
2
1
1
2
1
G_16290_075.eps
Figure 4-13 Fixation screws and LCD backlight connectors
1
G_16290_076.eps
310106
Figure 4-14 Location of LCD panel fixation screws
310106
EN 14EL1.1U AA4.
Figure 4-15 Conductive tape
4.4Set Re-assembly
To re-assemble the whole set, execute all processes in reverse
order.
Mechanical Instructions
1
G_16290_077.eps
310106
Notes:
•While re-assembling, make sure that all cables are placed
and connected in their original position. See Figure "Cable
dressing".
•Ensure that the conducting tape [1] at both sides of the
LCD panel is placed in its original position. See Figure
“Conductive tape”.
Service Modes, Error Codes, and Fault Finding
5.Service Modes, Error Codes, and Fault Finding
EN 15EL1.1U AA5.
Index of this chapter:
5.1 Test Points
5.2 Service Modes
5.3 Stepwise Start-up
5.4 Service Tools
5.5 Error Codes
5.6 The Blinking LED Procedure
5.7 Protections
5.8 Fault Finding and Repair Tips
5.9 Software Upgrading
5.1Test Points
As most signals are digital, it will be almost impossible to
measure waveforms with a standard oscilloscope. Therefore,
waveforms are not given in this manual. Several key ICs are
capable of generating test patterns, which can be controlled via
ComPair. In this way it is possible to determine which part is
defective.
Perform measurements under the following conditions:
•Service Default Mode.
•Video: Color bar signal.
•Audio: 3 kHz left, 1 kHz right.
5.2Service Modes
Service Default Mode (SDM) and Service Alignment Mode
(SAM) offer several features for the service technician, while
the Customer Service Mode (CSM) is used for communication
between a Customer Helpdesk and a customer.
There is also the option of using ComPair, a hardware interface
between a computer (see requirements below) and the TV
chassis. It offers the ability of structured troubleshooting, test
pattern generation, error code reading, software version
readout, and software upgrading.
Minimum requirements for ComPair: a Pentium processor,
Windows 95/98, and a CD-ROM drive (see also paragraph
“ComPair”).
Remark: as the Hotel Mode is a User Mode, rather than a
Service Mode, we have put the description in Chapter 3,
Directions for Use.
•Tuning frequency 61.25 MHz for NTSC: The TV shall tune
to physical channel 3 only if channel 3 is an analog channel
or if there is no channel 3 installed in the channel map. If
there is a digital channel installed in channel 3, then the
frequency to which the set will tune, would be as specified
in the channel map and could be different from the one
corresponding to the physical channel 3.
•All picture settings at 50% (brightness, color, contrast).
•All sound settings at 50%, except volume at 25%.
•All service-unfriendly modes (if present) are disabled, like:
– (Sleep) timer.
– Child/parental lock.
– Picture mute (blue mute or black mute).
– Automatic volume levelling (AVL).
– Auto switch "off" (when no video signal was received
for 10 minutes).
– Skip/blank of non-favorite pre-sets.
– Smart modes.
– Auto store of personal presets.
– Auto user menu time-out.
How to Activate SDM
Use one of the following methods:
•Use the standard RC-transmitter and key in the code
“062596”, directly followed by the “MENU” button.
Note: It is possible that, together with the SDM, the main
menu will appear. To switch it "off", push the “MENU”
button again.
•Short for a moment the two solder pads [1] on the SSB,
with the indication “SDM”. They are located on top of the
SSB. Activation can be performed in all modes, except
when the set has a problem with the Stand-by Processor.
See figure “SDM and SPI service pads”.
12
SDMSPI
5.2.1Service Default Mode (SDM)
Purpose
•To create a pre-defined setting, to get the same
measurement results as given in this manual.
•To override SW protections (only applicable for protections
detected by stand-by processor) and make the TV start up
to the step just before protection (a sort of automatic
stepwise start up). See paragraph “Stepwise Start Up”.
•To start the blinking LED procedure (not valid in protection
mode).
After activating this mode, “SDM” will appear in the upper right
corner of the screen (if you have picture).
How to Navigate
When you press the “MENU” button on the RC transmitter, the
set will toggle between the SDM and the normal user menu
(with the SDM mode still active in the background).
How to Exit SDM
Use one of the following methods:
•Switch the set to STAND-BY via the RC-transmitter.
•Via a standard customer RC-transmitter: key in “00”sequence.
EN 16EL1.1U AA5.
Service Modes, Error Codes, and Fault Finding
5.2.2Service Alignment Mode (SAM)
Purpose
•To perform (software) alignments.
•To change option settings.
•To easily identify the used software version.
•To view operation hours.
•To display (or clear) the error code buffer.
How to Activate SAM
Via a standard RC transmitter: key in the code “062596”
directly followed by the “INFO” button. After activating SAM
with this method a service warning will appear on the screen,
you can continue by pressing the red button on the RC.
Contents of SAM:
•Hardware Info.
– A. VIPER SW Version. Displays the software version
of the VIPER software (main software) (example:
EL23U-1.2.3.4_12345 = AAAAB_X.Y.W.Z_NNNNN).
•AAAA= the chassis name.
•B= the region: A= AP, E= EU, L= Latam, U = US.
•X.Y.W.Z= the software version, where X is the
main version number (different numbers are not
compatible with one another) and Y is the sub
version number (a higher number is always
compatible with a lower number). The last two
digits are used for development reasons only, so
they will always be zero in official releases.
•NNNNN= last five digits of 12nc code of the
software.
– B. SBY PROC Version. Displays the software version
of the stand-by processor.
– C. Production Code. Displays the production code of
the TV, this is the serial number as printed on the back
of the TV set. Note that if an NVM is replaced or is
initialized after corruption, this production code has to
be re-written to NVM. ComPair will foresee in a
possibility to do this.
•Operation Hours. Displays the accumulated total of
operation hours (not the stand-by hours). Every time the
TV is switched "on/off", 0.5 hours is added to this number.
•Errors. (Followed by maximal 10 errors). The most recent
error is displayed at the upper left (for an error explanation
see paragraph “Error Codes”).
•Defective Module. Here the module that generates the
error is displayed. If there are multiple errors in the buffer,
which are not all generated by a single module, there is
probably another defect. It will then display the message
“UNKNOWN” here.
•Reset Error Buffer. When you press “cursor right” and
then the “OK” button, the error buffer is reset.
•Alignments. This will activate the “ALIGNMENTS” submenu.
•Dealer Options. Extra features for the dealers.
•Options. Extra features for Service.
•Initialize NVM. When an NVM was corrupted (or replaced)
in the former EMG based chassis, the microprocessor
replaces the content with default data (to assure that the
set can operate). However, all preferences and alignment
values are gone now, and option numbers are not correct.
Therefore, this was a very drastic way. In this chassis, the
procedure is implemented in another way: The moment the
processor recognizes a corrupted NVM, the “initialize
NVM” line will be highlighted. Now, you can do two things
(dependent of the service instructions at that moment):
– Save the content of the NVM via ComPair for
development analysis, before initializing. This will give
the Service department an extra possibility for
diagnosis (e.g. when Development asks for this).
– Initialize the NVM (same as in the past, however now it
happens conscious).
Note: When you have a corrupted NVM, or you have replaced
the NVM, there is a high possibility that you will not have picture
any more because your display option is not correct. So, before
you can initialize your NVM via the SAM, you need to have a
picture and therefore you need the correct display option. To
adapt this option, use ComPair. The correct HEX values for the
options can be found in the table below.
•Store. All options and alignments are stored when
pressing “cursor right” and then the “OK”-button
•SW Maintenance.
– SW Events. Not useful for service purposes. In case of
specific software problems, the development
department can ask for this info.
EN 18EL1.1U AA5.
Service Modes, Error Codes, and Fault Finding
– HW Events. Not functional at the moment this manual
is released, description will be published in an update
manual if the function becomes available.
How to Navigate
•In SAM, you can select the menu items with the “CURSOR
UP/DOWN” key on the RC-transmitter. The selected item
will be highlighted. When not all menu items fit on the
screen, move the “CURSOR UP/DOWN” key to display the
next/previous menu items.
•With the “CURSOR LEFT/RIGHT” keys, it is possible to:
– (De) activate the selected menu item.
– (De) activate the selected submenu.
How to Exit SAM
Use one of the following methods:
•Press the “MENU” button on the RC-transmitter.
•Switch the set to STAND-BY via the RC-transmitter.
Note: As long as SAM is activated, it is not possible to change
a channel. This could hamper the White Point alignments
because you cannot choose your channel/frequency any more.
Workaround: after you have sent the RC code “062596 INFO”
you will see the service-warning screen, and in this stage it is
still possible to change the channel (so before pressing the
“OK” button).
5.2.3Customer Service Mode (CSM)
Purpose
When a customer is having problems with his TV-set, he can
call his dealer or the Customer Helpdesk. The service
technician can then ask the customer to activate the CSM, in
order to identify the status of the set. Now, the service
technician can judge the severity of the complaint. In many
cases, he can advise the customer how to solve the problem,
or he can decide if it is necessary to visit the customer.
The CSM is a read only mode; therefore, modifications in this
mode are not possible.
How to Activate CSM
Key in the code “123654” via the standard RC transmitter.
Note: Activation of the CSM is only possible if there is no (user)
menu on the screen!
How to Navigate
By means of the “CURSOR-DOWN/UP” knob on the RCtransmitter, you can navigate through the menus.
Contents of CSM
•SW Version (example: EL23U-1.2.3.4_12345). Displays
the built-in main software version. In case of field problems
related to software, software can be upgraded. As this
software is consumer upgradable, it will also be published
on the Internet.
•SBY Processor Version. Displays the built-in stand-by
processor software version. Upgrading this software will be
possible via a PC and a ComPair interface (see chapter
Software upgrade).
•Set Type. This information is very helpful for a helpdesk/
workshop as reference for further diagnosis. In this way, it
is not necessary for the customer to look at the rear of the
TV-set. Note that if an NVM is replaced or is initialized after
corruption, this set type has to be re-written to NVM.
ComPair will foresee a possibility to do this.
•Production Code. Displays the production code (the serial
number) of the TV. Note that if an NVM is replaced or is
initialized after corruption, this production code has to be
re-written to NVM. ComPair will foresee a possibility to do
this.
•Code 1. Gives the latest five errors of the error buffer. As
soon as the built-in diagnose software has detected an
error the buffer is adapted. The last occurred error is
displayed on the leftmost position. Each error code is
displayed as a 2-digit number. When less than 10 errors
occur, the rest of the buffer is empty (00). See also
paragraph Error Codes for a description.
•Code 2. Gives the first five errors of the error buffer. See
also paragraph Error Codes for a description.
•Headphone Volume. Gives the last status of the
headphone volume, as set by the customer. The value can
vary from 0 (volume is minimum) to 100 (volume is
maximum). Change via ”MENU”, “TV”, “SOUND”,
“HEADPHONE VOLUME”.
•Dolby. Indicates whether the received transmitter
transmits Dolby sound (“ON”) or not (“OFF”). Attention: The
presence of Dolby can only be tested by the software on
the Dolby Signaling bit. If a Dolby transmission is received
without a Dolby Signaling bit, this indicator will show “OFF”
even though a Dolby transmission is received.
•Sound Mode. Indicates the by the customer selected
sound mode (or automatically chosen mode). Possible
values are “STEREO” and “VIRTUAL DOLBY
SURROUND”. Change via “MENU”, “TV”, “SOUND”,
“SOUND MODE”. It can also have been selected
automatically by signaling bits (internal software).
•Tuner Frequency. Not applicable for US sets.
•Digital Processing. Indicates the selected digital mode.
Possible values are “STANDARD” and “PIXEL PLUS”.
Change via “MENU”, “TV”, “PICTURE”, “DIGITAL
PROCESSING”.
•TV System. Gives information about the video system of
the selected transmitter.
– M: NTSC M signal received
– ATSC: ATSC signal received
•Center Mode. Not applicable.
•DNR. Gives the selected DNR setting (Dynamic Noise
Reduction), “OFF”, “MINIMUM”, “MEDIUM”, or
“MAXIMUM”. Change via “MENU”, “TV”, “PICTURE”,
“DNR”
•Noise Figure. Gives the noise ratio for the selected
transmitter. This value can vary from 0 (good signal) to 127
(average signal) and to 255 (bad signal). For some
software versions, the noise figure will only be valid when
“Active Control” is set to “medium” or “maximum” before
activating CSM.
•Source. Indicates which source is used and the video/
audio signal quality of the selected source. (Example:
Tuner, Video/NICAM) Source: “TUNER”, “AV1”, “AV2”,
“AV3”, “HDMI 1”, “SIDE”. Video signal quality: “VIDEO”, “SVIDEO”, “RGB 1FH”, “YPBPR 1FH 480P”, “YPBPR 1FH
576P”, “YPBPR 1FH 1080I”, “YPBPR 2FH 480P”, “YPBPR
2FH 576P”, “YPBPR 2FH 1080I”, “RGB 2FH 480P”, “RGB
2FH 576P” or “RGB 2FH 1080I”. Audio signal quality:
“STEREO”, “SPDIF 1”, “SPDIF 2”, or “SPDIF”.
•Audio System. Gives information about the audible audio
system. Possible values are “Stereo”, ”Mono”, “Mono
selected”, “Analog In: No Dig. Audio”, “Dolby Digital 1+1”,
“Dolby Digital 1/0”, “Dolby Digital 2/0”, “Dolby Digital 2/1”,
“Dolby Digital 2/2”, “Dolby Digital 3/0”, “Dolby Digital 3/1”,
“Dolby Digital 3/2”, “Dolby Digital Dual I”, “Dolby Digital
Dual II”, “MPEG 1+1”, “MPEG 1/0”, “MPEG 2/0”. This is the
same info as you will see when pressing the “INFO” button
in normal user mode (item “signal”). In case of ATSC
receiving there will be no info displayed.
•Tuned Bit. Indicates if the selected preset is automatically
tuned (via “Automatic Installation” in the setup menu) or via
the automatic tuning system of the TV. In this case “Tuned
bit” will show “YES”. If the TV was not able to auto-tune to
the correct frequency, this item will show “NO”. So if “NO”
is displayed, it could indicate that the customer has
manually tuned to a frequency which was too far from a
correct frequency, that the TV was not able to auto-tune
any more.
•Preset Lock. Indicates if the selected preset has a child
lock: “LOCKED” or “UNLOCKED”. Change via “MENU”,
“TV”, “CHANNELS”, “CHANNEL LOCK”.
Service Modes, Error Codes, and Fault Finding
EN 19EL1.1U AA5.
•Lock After. Indicates at what time the channel lock is set:
“OFF” or e.g. “18:45” (lock time). Change “MENU”, “TV”,
“CHANNELS”, “LOCK AFTER”.
•TV Ratings Lock. Indicates the “TV ratings lock” as set by
the customer. Change via “MENU”, “TV”, “CHANNELS”,
“TV RATINGS LOCK”. Possible values are: “ALL”,
“NONE”, “TV-Y”, “TV-Y7”, “TV-G”, “TV-PG”, “TV-14” and
“TV-MA”.
•Movie Ratings Lock. Indicates the “Movie ratings lock” as
set by the customer. Change via “MENU”, “TV”,
“CHANNELS”, “MOVIE RATINGS LOCK”. Possible values
are: “ALL”, “NR”, “G”, “PG”, “PG-13”, “R”, “NC-17” and “X”.
•V-Chip Tv Status. Indicates the setting of the V-chip as
applied by the selected TV channel. Same values can be
shown as for “TV RATINGS LOCK”.
•V-Chip Movie Status. Indicates the setting of the V-chip
as applied by the selected TV channel. Same values can
be shown as for “MOVIE RATINGS LOCK”.
•Options 1. Gives the option codes of option group 1 as set
in SAM (Service Alignment Mode).
•Options 2. Gives the option codes of option group 2 as set
in SAM (Service Alignment Mode).
•AVL. Indicates the last status of AVL (Automatic Volume
Level): “ON” or “OFF”. Change via “MENU”, “TV”,
“SOUND”, “AVL”. AVL can not be set in case of digital
audio reception (e.g. Dolby Digital or AC3)
•Delta Volume. Indicates the last status of the delta volume
for the selected preset as set by the customer: from “-12”
to “+12”. Change via “MENU”, “TV”, “SOUND”, “DELTA
VOLUME”.
•HDMI key validity. Indicates the key’s validity.
•IEEE key validity. Indicates the key’s validity (n.a.).
•POD key validity. Indicates the key’s validity (n.a.).
•Digital Signal Quality. Indicates quality of the received
digital signal (0= low).
How to Exit CSM
Press any key on the RC-transmitter (with exception of the
“CHANNEL +/-”, “VOLUME”, “MUTE” and digit (0-9) keys).
5.3Stepwise Start-up
The stepwise start-up method, as known from FTL/FTP sets is
not valid any more. The situation for this chassis is as follows:
when the TV is in a protection state detected via the Stand-by
Processor (and thus blinking an error) and SDM is activated via
shortcutting the pins on the SSB, the TV starts up until it
reaches the situation just before protection. So, this is a kind of
automatic stepwise start-up. In combination with the start-up
diagrams below, you can see which supplies are present at a
certain moment.
Important to know here is, that if e.g. the 3V3 detection fails
(and thus error 11 is blinking) and the TV is restarted via SDM,
the Stand-by Processor will enable the 3V3, but will not go to
protection now. The TV will stay in this situation until it is reset
(Mains/AC Power supply interrupted).
The abbreviations “SP” and “MP” in the figures stand for:
•SP: protection or error detected by the Stand-by Processor.
•MP: protection or error detected by the VIPER Main Processor.
Mains
“off”
- WakeUp requested
- Acquisition needed
Stand-by
(Off St-by)
- POD Card remove
- Tact SW pushed
- No data Acquisition required
and no POD present
- Tact SW pushed
- WakeUp requested
- Acquisition needed
d
POD
Stand-by
On
Only applicable for sets with CableCARDTM slot (POD)
*
No data Acquisition
required and
POD present
*
Off
Mains
“on”
Semi
Stand-by
GoToProtection
GoToProtec
tion
WakeUp
requested
- St-by requested
- Tact SW pushed
WakeUp
requested
Protection
Active
GoToProtection
F_15400_095.eps
020206
Figure 5-2 Transition diagram
EN 20EL1.1U AA5.
Service Modes, Error Codes, and Fault Finding
Off
Mains is appl ied
Standby Supply starts running.
+5V2, 1V2Stb, 3V3Stb and +2V5D become present.
In case of PDP 3V3 Vpr to CPU PDP becomes present.
st-by µP resets
All I/O lines have a “high” default state:
- Sound-Enable and Reset-Audio should remain “high” .
- NVM power line is “high”, no NVM communication possible.
Initialise I/O pins of the st-by µP, start keyboard scanning, RC
CPU GO (inverse of the stby I/O line P OD-M OD E) and P DP GO
are then both “low” and the PDP is in the “low power” mode.
Switch “low” the NVM power reset line. Add a 2ms delay
before trying to address the NVM to allow correct NVM
Switch “on” all supplies by switching LOW the POD-MODE
+5V, +8V6, +12VS, +12VSW and Vsound are switched on
- Assert the Viper reset.
detection, P50 decoding. Wake up reasons are “off”.
In case of FHP PDP: Switch PDPGO “low”
initialization.
and the ON -M ODE I /O lines.
Wait 50ms and then start polling t he detect-
5V, detect-8V6 and detect-12V every 40ms.
Stand-by or
Protection
If the protection state was left by short circuiting the
SDM pins, detection of a protection condition during
startup will stall the startup. Protection conditions in a
playing set will be ignored. The protection mode will
- Switch Sound-Enable and Reset-Audio “high”.
not be entered.
They are “low” in the standby mode if the
standby mode lasted longer than 2s.
*
Switching the POD-MODE and the
Swi tching the P OD -MO DE
low in an FHP PDP set
makes the CP U GO go “high”
and starts the P DP CP U .
except in an FHP PDP Cold
Boot
“on” mode “low” in an SDI PDP set
makes the PD P supplies go t o the
*
“on” mode. Within 4 seconds, a
valid LVDS must be sent to the
display to prev ent prote ction.
(valid for V3 version)
*
The availability of the supplies is check ed through detect signals (delivered by
dedicated detect-IC's) going to the st-by µP. These signals are available for
+12V, +8V6, +5V, +1V2 and +2V5. A low to high transition of the signals should
occur within a certain time after toggling the standby line. If an observers is
detected before the time-out elapses, of course, the process should continue in
order to minimize start up time.
action holder: M I P S
action holder: St-by
autonomous acti on
*
Switching the PDPGO “high”
will give a visual arte fact a nd
should only be done if really
necessary.
detect-5V
received within
2900 ms after POD-MOD E
toggle?
Yes
activate +5V supply detection algorithm
detect-12VSW received within
2900 ms after POD -mode
toggle?
Yes
activate +12VSW supply
detection algorithm
*
No need to wait for the 8V6 detection at this point.
No
PDP should start: 5V, 8V6 and
Yes
No
FHP PDP Set?
Yes
Switch PDPGO high:
12V are activated
detect-5V
received within
2900 ms after PD PGO
toggle?
+12V error
SP
detect-8V6 received
within 6300 ms after POD-mode toggle?
Startup shall not wait for this detection
and continue startup.
No
+5V error
No
SP
*
Yes
Enable the +1V2 supply (ENABLE-1V2)
Start polling the detect-1V2 every 40ms
To part BTo part B
Only applicable for sets with CableCARDTM slot (POD)
*
Figure 5-3 “Off” to “Semi Stand-by” flowchart (part 1)
No
+8V6 erro r
SP
activate +8V6 supply
detection algorithm
return
F_15400_096a.eps
020206
Service Modes, Error Codes, and Fault Finding
EN 21EL1.1U AA5.
From part A
No
From part B
detect-1V2
received within
250ms?
Yes
Enable the supply for
+2.5V and +3.3V (ENABLE-3V3)
Start polling the detect-3V3 every 40ms
detect-3V3
received within
250 ms?
Yes
Activate supply detection algorithms for
+1V2 and +3V3
SUP PLY -FAULT I/O l ine
is High?
Yes
Enable the supply fault detection
interrupt
action holder: MIPS
action holder: St-by
autonomous action
No
+1.2V error
SP
No separate enable and
detect is present for the +2V5
supply in the Baby Jaguar.
+3.3V errorNo
SP
Supply fault errorNo
SP
No
No
Release viper reset
Feed warm boot script(2)
Set I²C slave address
of Standby µP to (A0h)
Detect EJ TAG debug probe
(pulling pin of the probe interface to
ground by inserting EJTAG probe)
EJTAG probe
connected ?
No
Cold boot?
Yes
Release viper reset
Feed cold boot script(1)
Release PNX2015 reset 100ms after
Viper reset is released
Bootscript ready
in 1250 ms?
Yes
Set I²C slave address
of Standby µP to (64h)
RPC start (comm . protocol)
Yes
Release viper reset
Feed initializing boot script (3)
disable alive mechanism
Release PNX2015 reset 100ms
after Viper reset is released
No
Flash to RAM im age
transfer succeeded
within 30s?
Yes
Viper SW initialization
succeeded
within 20s?
Code = 5
Switch Viper in reset
No
Code = 53
To part CTo part CTo part CTo part C
F_15400_096b.eps
Figure 5-4 “Off” to “Semi Stand-by” flowchart (part 2)
260505
EN 22EL1.1U AA5.
Service Modes, Error Codes, and Fault Finding
From part BFrom part BFrom part B
Yes
Enable Alive check mechanism
MIPS reads the wake up reason
from standby µP.
SDI PDP
Set?
No
FHP PDP
Set?
Switch “on” the LVDS output of
*
the PNX2015 with a correct
clock frequency within 4s after
Yes
switching the POD and “on”
mode to prevent PD P dis play
supply protection.
These LVDS items are
SDI V3 display only !!
Yes
Send STBYEN = 1
to PDP display (I²C)
PFCON = 1
VCCON = 1
Wait until Viper starts to
communicate
3-th try?
Yes
Log Code as
error code
SP
Wait 10ms
Switch the NVM reset
line HI GH .
Disable all supply related protections and
switch off the +2V5, +3V3 DC/DC converter.
Wait 5ms
switch off the remaining DC/DC
converters
Switch POD-MODE and ON-MODE
I/O line “hi gh”.
*
Wait for the +8V6 to be d e te cted if not yet present. (if
it does not come, the standby µP will enter a
protection mode, this is not a dead end here)
PWR-OK-PDP
received within 10s
after POD and “on” mode
toggle ?
Yes
Init SDI PDP
Switch LVDS back off if
end state is not the active
state.
Switch PDPGO “ low”
*
action holder: M IPS
action holder: St-by
autonomous action
No
Log display
error and enter
protection mode
SP
No
Start 4 seconds preheating timer in case of
a LPL scanning backlight LCD set.
AVIP needs to be started before the MPIF in order to have a good clock distribution.
AVIP default power-up mode is Standby. The Viper instructs AVIP via I²C to enable all the
PLLs and clocks and hence enter to Full Power mode.
Initialize PNX2015 HD subsystem
MPI Fs shoul d be initialized
MPIF should deliver 4 observers:
POR= 0; normal operation
MSUP = 1: Main supply is present
ASUP = 1; audio supply is present
ROK = 1; reference frequency is present (coming from AVIP)
All observers present with correct state?
Yes
Initialize tuners and HDMI
Initialize source selection
Initialize video processing ICs
- Spider (if available)
No
Init FHP PDP
Log appropriate
Observer error
Do not enter semi-standby state in case of an LPL
scanning backlight LCD set before 4 s preheating timer has
elapsed.
Only applicable for sets with CableCARDTM slot (POD)
*
Figure 5-5 “Off” to “Semi Stand-by” flowchart (part 3)
Initialize Columbus
Initialize 3D Combfilter
Initialize AutoTV
Semi-Stand-by
F_15400_096c.eps
020206
Service Modes, Error Codes, and Fault Finding
EN 23EL1.1U AA5.
action holder: M IP S
action holder: St-by
autonomous action
26" /32" / 37" / 42" LCD LP L
Semi Standby
Wait until previous on-state is left more than 2
seconds ago. (to prevent LCD display problems)
Assert RGB video blanking
and audio m ute
Initialize audio and video processing ICs and
functions according needed use case.
Wait unti l QV CP generates a valid LVDS output
clock.
Switch “on” 12V LCD supply
(LCD-Power-on)
Start to apply valid interface signals to the module (LVDS) within a time
frame of min. 17.5ms to max. 67.5ms after supply switch “on”.
In implementation, use 25ms, this makes it compatible with 37HD"Sharp
(t=17.5ms is the supply switch-on delay taken into account)
Wait 250ms (min. = 200ms)
Switch “off” RGB blanking
Switch “on” LCD lamp after valid, stable video, corresponding
to the requested output is delivered by the Viper
Switch Audio-Reset and sound enable “low” and demute
Active
Figure 5-6 “Semi Stand-by” to “Active” flowchart
G_16290_079.,eps
020206
EN 24EL1.1U AA5.
Service Modes, Error Codes, and Fault Finding
26" /32" / 37" / 42" LCD LP L
action holder: M IP S
Active
Mute al l sound outputs.
Switch reset-audio and sound-enable
lines “high ”.
Switch “off” LCD lamp.
Mute al l video outputs.
Wait 250ms (min. = 200ms).
action holder: St-by
autonomous action
Switch “off” LVDS signal
(Viper I/O: PD-LVDS).
Switch “off” 12V LCD supply within a time frame of min.
0.5 ms to max. 50ms after LVDS switch “off”.
(Viper I/O: LCD _PWR_ON ).
Semi Standby
Figure 5-7 “Active” to “Semi Stand-by” flowchart
G_16290_080.eps
020206
Service Modes, Error Codes, and Fault Finding
EN 25EL1.1U AA5.
*
POD
Transfer Wake up reasons to the
Images are re-transferred to DDR-RAM from
Flash RAM (verification through checksum).
MIPS image completes the application reload,
stops DDR-RAM access, puts itself in a
sleepmode, and signals the standby µP when
the Stand-by mode can be entered.
DDR-RAM is put in self refresh mode and the images
are kept in the hibernating DDR-RAM.
Stand- by µP.
Wait 5ms
Semi Stand-by
action holder: MIPS
action holder: St-by
autonomous action
Important remark:
release RESET AUDIO and
SOUND_ENABLE 2 sec after
entering stand-by to save power
Switch Viper in reset state
Wait 10ms
Switch the NVM reset line “high”.
Disable all supply related protections and switch “off”
the +2V5, +3V3 DC/DC converter.
Wait 5ms
Switch “off” the remaining DC/DC converters
Switch “off” all supplies by switching “high” the POD-
MODE and the ON-MODE I/O lines.
*
For PDP this means
CPUGO becomes low.
Only applicable for sets with CableCARDTM slot (POD)
*
Figure 5-8 “Semi Stand-by” to “Stand-by” flowchart
Stand-by
F_15400_099.eps
020206
EN 26EL1.1U AA5.
Service Modes, Error Codes, and Fault Finding
action holder: MIPS
action holder: St-by
autonomous action
If needed to speed up this transition,
this block could be omitted. This is
depending on the outcome of the
safety investigations.
min. 0.5ms to max. 50ms after LVDS switch “off”. (for LCD sets)
MP
Log the appropriate error and
set stand-by flag in NVM
Redefine wake up reasons for protection
state and transfer to stand-by µP.
Switch “off” LCD lamp supply (for LCD sets)
Wait 250ms (min. = 200ms)
Switch “off” LVDS signal
Switch “off” 12V LCD supply within a time frame of
Ask stand-by µP to enter protection state
SP
Switch Viper in reset state
Wait 10ms
Switch the NVM reset line “high”.
Disable all supply related protections and switch “off”
the +2V5, +3V3 DC/DC converter.
Wait 5ms
Switch “off” the remaining DC/DC converters
Switch “off” all supplies by switching “high” the POD-
MODE and the ON-MODE I/O lines.
Flash LED in order to indicate
protection state.
*
Only applicable for sets with CableCARDTM slot (POD)
*
Figure 5-9 “Protection” flowchart
Protection
F_15400_102.eps
020206
Service Modes, Error Codes, and Fault Finding
5.4Service Tools
5.4.1ComPair
Introduction
ComPair (Computer Aided Repair) is a service tool for Philips
Consumer Electronics products. ComPair is a further
development on the European DST (service remote control),
which allows faster and more accurate diagnostics. ComPair
has three big advantages:
1. ComPair helps you to quickly get an understanding on how
to repair the chassis in a short time by guiding you
systematically through the repair procedures.
2. ComPair allows very detailed diagnostics (on I
is therefore capable of accurately indicating problem areas.
You do not have to know anything about I
yourself because ComPair takes care of this.
3. ComPair speeds up the repair time since it can
automatically communicate with the chassis (when the
microprocessor is working) and all repair information is
directly available. When ComPair is installed together with
the Force/SearchMan electronic manual of the defective
chassis, schematics and PWBs are only a mouse click
away.
Specifications
ComPair consists of a Windows based fault finding program
and an interface box between PC and the (defective) product.
The ComPair interface box is connected to the PC via a serial
(or RS-232) cable.
For this chassis, the ComPair interface box and the TV
communicate via a bi-directional service cable via the service
connector(s).
The ComPair fault finding program is able to determine the
problem of the defective television. ComPair can gather
diagnostic information in two ways:
•Automatically (by communicating with the television):
ComPair can automatically read out the contents of the
entire error buffer. Diagnosis is done on I
ComPair can access the I
ComPair can send and receive I
the microcontroller of the television. In this way, it is
possible for ComPair to communicate (read and write) to
devices on the I
2
C/UART buses of the TV-set.
•Manually (by asking questions to you): Automatic
diagnosis is only possible if the microcontroller of the
television is working correctly and only to a certain extent.
When this is not the case, ComPair will guide you through
the fault finding tree by asking you questions (e.g. Does the
screen give a picture? Click on the correct answer: YES /
NO) and showing you examples (e.g. Measure test-point I7
and click on the correct oscillogram you see on the
oscilloscope). You can answer by clicking on a link (e.g.
text or a waveform picture) that will bring you to the next
step in the fault finding process.
By a combination of automatic diagnostics and an interactive
question / answer procedure, ComPair will enable you to find
most problems in a fast and effective way.
Note: If you encounter any problems, contact your local
support desk.
5.4.2LVDS Tool
Introduction
This service tool (also called “ComPair Assistant 1“) may help
you to identify, in case the TV does not show any picture,
whether the Small Signal Board (SSB) or the display of a Flat
TV is defective.
Furthermore it is possible to program EPLDs with this tool (Byte
blaster). Read the user manual for an explanation of this
feature.
Since 2004, the LVDS output connectors in our Flat TV models
are standardized (with some exceptions). With the two
delivered LVDS interface cables (31p and 20p) you can cover
most chassis (in special cases, an extra cable will be offered).
When operating, the tool will show a small (scaled) picture on
a VGA monitor. Due to a limited memory capacity, it is not
possible to increase the size when processing high-resolution
LVDS signals (> 1280x960). Below this resolution, or when a
DVI monitor is used, the displayed picture will be full size.
Generally this tool is intended to determine if the SSB is
working or not. Thus to determine if LVDS, RGB, and sync
signals are okay.
How to Connect
Connections are explained in the user manual, which is packed
with the tool.
EN 27EL1.1U AA5.
TO
I2C SERVICE
CONNECTOR
180804
How to Connect
This is described in the chassis fault finding database in
ComPair.
Caution: It is compulsory to connect the TV to the PC as
shown in the picture below (with the ComPair interface in
between), as the ComPair interface acts as a level shifter. If
one connects the TV directly to the PC (via UART), ICs will be
blown!
Note: To use the LVDS tool, you must have ComPair release
2004-1 (or later) on your PC (engine version >= 2.2.05).
For every TV type number and screen size, one must choose
the proper settings via ComPair. The ComPair file will be
updated regularly with new introduced chassis information.
How to Order
•LVDS tool (incl. two LVDS cables: 31p and 20p):
3122 785 90671.
•LVDS tool Service Manual:
3122 785 00810.
EN 28EL1.1U AA5.
Service Modes, Error Codes, and Fault Finding
5.5Error Codes
5.5.1Introduction
The error code buffer contains all detected errors since the last
time the buffer was erased. The buffer is written from left to
right, new errors are logged at the left side, and all other errors
shift one position to the right.
When an error has occurred, the error is added to the list of
errors, provided the list is not full or the error is a protection
error.
When an error occurs and the error buffer is full, then the new
error is not added, and the error buffer stays intact (history is
maintained), except when the error is a protection error.
To prevent that an occasional error stays in the list forever, the
error is removed from the list after 50+ operation hours.
When multiple errors occur (errors occurred within a short time
span), there is a high probability that there is some relation
between them.
Basically there are three kinds of errors:
•Errors detected by the Stand-by Processor. These
errors will always lead to protection and an automatic start
of the blinking LED for the concerned error (see paragraph
“The Blinking LED Procedure”). In these cases SDM can
be used to start up (see chapter “Stepwise Start-up”).
•Errors detected by VIPER that lead to protection. In this
case the TV will go to protection and the front LED will blink
at 3 Hz. Further diagnosis via service modes is not possible
here (see also paragraph “Error Codes” -> “Error Buffer” > “Extra Info”).
•Errors detected by VIPER that do not lead to protection. In this case the error can be read out via
ComPair, via blinking LED method, or in case you have
picture, via SAM.
5.5.2How to Read the Error Buffer
Use one of the following methods:
•On screen via the SAM (only if you have a picture). E.g.:
– 00 00 00 00 00: No errors detected
– 06 00 00 00 00: Error code 6 is the last and only
detected error
– 09 06 00 00 00: Error code 6 was first detected and
error code 9 is the last detected error
•Via the blinking LED procedure (when you have no
picture). See next paragraph.
•Via ComPair.
5.5.3How to Clear the Error Buffer
Use one of the following methods:
•By activation of the “RESET ERROR BUFFER” command
in the SAM menu.
•With a normal RC, key in sequence “MUTE” followed by
“062599” and “OK”.
•If the content of the error buffer has not changed for 50+
hours, it resets automatically.
5.5.4Error Buffer
In case of non-intermittent faults, clear the error buffer before
you begin the repair (before clearing the buffer, write down the
content, as this history can give you significant information).
This to ensure that old error codes are no longer present.
If possible, check the entire contents of the error buffer. In
some situations, an error code is only the result of another error
code and not the actual cause (e.g., a fault in the protection
detection circuitry can also lead to a protection).
There are several mechanisms of error detection:
•Via error bits in the status registers of ICs.
•Via polling on I/O pins going to the stand-by processor.
•Via sensing of analogue values on the stand-by processor.
•Via a “not acknowledge” of an I
2
C communication
Take notice that some errors need more than 90 seconds
before they start blinking. So in case of problems wait 2
minutes from start-up onwards, and then check if the front LED
is blinking.
Table 5-3 Error code overview
ErrorDescriptionError/ProtDetected by DeviceDefective moduleResult
1
I2C1
2
I2C2
2
3
I
C3
2
4
5VIPER does not boot (hardware failure)PStby µPPNX8550Protection + Error blinking
65V supplyPStby µPn.a.Protection + Error blinking
81.2V DC/DCPStby µPn.a.Protection + Error blinking
113.3V DC/DCPStby µPn.a.Protection + Error bl i nking
1212V supplyPStby µPn.a.Protection + Error blinking
14Supply Class D amplifiersPStby µPProtection + Error blinking
17MPIF1 Audio Supply (ASUP)EVIPERPNX3000IF I/OError logged
18MPIF1 ref freqEVIPE RPNX3000IF I/OError logged
25Supply faultPStby µPProtection + Error blinking
27PhoenixEVIPERPNX2015BHD subsystemError logged
29AVI P1EVIPERPNX2015AV input processor 1Error logged
32MPIF1EVIPERKN10241CAnalog Front End 1Error logged
34Tuner1EVIPERTuner 1Error logged
37Channel decoderEVIPERNXT2003Error logged
43Hi Rate Front EndEVIPERTDA8751HDMIError logged
45Columbus 1EVIPERPNX2015Comb filterError logged
53VIP ER does not boot (software failure)PStby µPPNX8550Protection + Error blink ing
63PDP DisplayPVIPERDisplayProtection + 3 Hz blinking
Extra Info
•Error 1 (I
C4
I
2
C bus 1 blocked). When this error occurs, the
TV will go to protection and the front LED will blink at 3 Hz.
Now you can partially restart the TV via the SDM shortcut
pins on the SSB. Depending on the software version it is
possible that no further diagnose (error code read-out) is
possible. With the knowledge that only errors 1, 2, 4, and
63 result in a 3 Hz blinking LED, the range of possible
defects is limited.
•Error 2 (I
2
C bus 2 blocked). When this error occurs, the
TV will go to protection and the front LED will blink at 3 Hz.
Now you can partially restart the TV via the SDM shortcut
Service Modes, Error Codes, and Fault Finding
EN 29EL1.1U AA5.
pins on the SSB. Due to hardware restriction (I2C bus 2 is
the fast I
2
C bus) it will be impossible to start up the VIPER
and therefore it is also impossible to read out the error
codes via ComPair or via the blinking LED method. With
the knowledge that only errors 1, 2, 4, and 63 result in a 3
Hz blinking LED, the range of possible defects is limited.
When you have restarted the TV via the SDM shortcut pins,
and then pressed "CH+" on your remote control, the TV will
go to protection again, and the front LED blink at 3 Hz
again. This could be an indication that the problem is
related to error 2.
•Error 3 (I
on I
2
C bus 3 blocked). There are only three devices
2
C bus 3: VIPER, Stand-by Processor, and NVM. The
Stand-by Processor is the detection device of this error, so
this error will only occur if the VIPER or the NVM is blocking
the bus. This error will also be logged when the NVM gives
no acknowledge on the I
2
C bus (see error 44). Note that if
the 12 V supply is missing (connector 1M46 on the SSB),
the DC/DC supply on the SSB will not work. Therefore the
VIPER will not get supplies and could block I
a missing 12 V can also lead to an error 3.
•Error 4 (I
•Error 5 (I
severe hardware problem around the VIPER (supplies not
OK, VIPER completely dead, I
2
C bus 4 blocked). Same remark as with error 1.
2
C bus 5 blocked). This error will point to a
2
C link between VIPER and
2
C bus 3. So,
Stand-by Processor broken, etc. ...).
•Error 7 (8.6 V error). Except a physical problem with the
8.6 V itself, it is also possible that there is something wrong
with the Audio DC Protection: see paragraph "Hardware
Protections" for this.
•Error 12 (12 V error). Except a physical problem with the
12 V itself, it is also possible that there is something wrong
with the Audio DC Protection: see paragraph "Hardware
Protections" for this.
•Error 14 (Audio supply). This error is triggered in case of
too low voltage of the audio supplies and therefore a drop
of the audio supply voltage of below approx. 9 V per supply
rail (or lower than 18 V rail to rail). Also a DC voltage of
higher than 1 V DC on the speakers will lead to protection
and error 14 blinking. For LCD sets this circuit can be found
on schematic SA3, for PDP sets this can be found on
schematic C. It should be noted that for 26-inch models
there is only a supply link between the amplifiers and the
stand-by µC whereas in all other models this link is
implemented by Audio-Prot line pin 7 on 1 M02.
•Error 29 (AVIP1). This error will probably generate extra
errors. You will probably also see errors 32 (MPIF) and
error 31 (AVIP 2). Error 29 and 31 will always be logged
together due to the fact that both AVIPs are inside the
PNX2015 and are on the same I
2
C bus. In this case start
looking for the cause around AVIP (part of PNX2015).
•Error 31 (AVIP2). See info on error 29.
•Error 34 (Tuner 1). When this error is logged, it is not sure
that there is something wrong with the tuner itself. It is also
possible that there is something wrong with the
communication between channel decoder and tuner. See
schematic B2B.
•Error 37 (Channel decoder). This error will always log
error 34 (tuner) extra. This is due to the fact that the tuner
2
C bus is coming from the channel decoder.
I
•Error 44 (NVM). This error will never occur because it is
masked by error 3 (I
for error 3 checks on an I
2
C bus 3). The detection mechanism
2
C acknowledge of the NVM. If
NVM gives no acknowledge, the stand-by software
assumes that the bus is blocked, the TV goes to protection
and error 3 will be blinking.
•Error 53. This error will indicate that the VIPER has started
to function (by reading his boot script, if this would have
failed, error 5 would blink) but initialization was never
completed because of hardware peripheral problems
(NAND flash, ...) or software initialization problems.
Possible cause could be that there is no valid software
loaded (try to upgrade to the latest main software version).
5.6The Blinking LED Procedure
5.6.1Introduction
The blinking LED procedure can be split up into two situations:
•Blinking LED procedure in case of a protection detected by
the stand-by processor. In this case the error is
automatically blinked. This will be only one error, namely
the one that is causing the protection. Therefore, you do
not have to do anything special, just read out the blinks. A
long blink indicates the decimal digit, a short blink indicates
the units.
•Blinking LED procedure in the “on” state. Via this
procedure, you can make the contents of the error buffer
visible via the front LED. This is especially useful for fault
finding, when there is no picture.
When the blinking LED procedure is activated in the “on” state,
the front LED will show (blink) the contents of the error-buffer.
Error-codes > 10 are shown as follows:
5. When all the error-codes are displayed, the sequence
finishes with a LED blink of 3 s,
6. The sequence starts again.
Example: Error 12 9 6 0 0.
After activation of the SDM, the front LED will show:
1. 1 long blink of 750 ms (which is an indication of the decimal
digit) followed by a pause of 1.5 s,
2. 2 short blinks of 250 ms followed by a pause of 3 s,
3. 9 short blinks followed by a pause of 3 s,
4. 6 short blinks followed by a pause of 3 s,
5. 1 long blink of 3 s to finish the sequence,
6. The sequence starts again.
5.6.2How to Activate
Use one of the following methods:
•Activate the SDM. The blinking front LED will show the
entire contents of the error buffer (this works in “normal
operation” mode).
•Transmit the commands “MUTE” - “062500” - “OK” with a normal RC. The complete error buffer is shown.
Take notice that it takes some seconds before the blinking
LED starts.
•Transmit the commands “MUTE” - “06250x” - “OK” with a normal RC (where “x” is a number between 1 and
5). When x= 1 the last detected error is shown, x= 2 the
second last error, etc.... Take notice that it takes some
seconds before the blinking LED starts.
EN 30EL1.1U AA5.
Service Modes, Error Codes, and Fault Finding
5.7Protections
5.7.1Software Protections
Most of the protections and errors use either the stand-by
microprocessor or the VIPER controller as detection device.
Since in these cases, checking of observers, polling of ADCs,
filtering of input values are all heavily software based, these
protections are referred to as software protections.
There are several types of software related protections, solving
a variety of fault conditions:
•Protections related to supplies: check of the 12V, +5V,
+8V6, +1.2V, +2.5V and +3.3V.
•Protections related to breakdown of the safety check mechanism. E.g. since a lot of protection detections are
done by means of the VIPER, failing of the VIPER
communication will have to initiate a protection mode since
safety cannot be guaranteed anymore.
Remark on the Supply Errors
The detection of a supply dip or supply loss during the normal
playing of the set does not lead to a protection, but to a cold
reboot of the set.
Protections during Start-up
During TV start-up, some voltages and IC observers are
actively monitored to be able to optimize the start-up speed,
and to assure good operation of all components. If these
monitors do not respond in a defined way, this indicates a
malfunction of the system and leads to a protection. As the
observers are only used during start-up, they are described in
the start-up flow in detail (see paragraph “Stepwise Start-up").
5.7.2Hardware Protections
There is one hardware protection in this chassis: “Audio DC
Protection”. This protection occurs when there is a DC voltage
on the speakers. In that case the main supply is switched "off",
but the stand-by supply is still working.
For the Samsung V4 PDP displays, the 8V6 supply is switched
"off" and the LED on the display’s Main Supply blinks eleven
times, which means there is an overvoltage protection. The
front LED of the TV will blink error 7 (8V6 error).
In case of LCD supplies, the 12V supply will drop. This will be
detected by the stand-by processor, which will start blinking the
12 V error (error 12).
Repair Tip
•It is also possible that you have an audio DC protection
because of an interruption in one or both speakers (the DC
voltage that is still on the circuit cannot disappear through
the speakers).
5.8Fault Finding and Repair Tips
Read also paragraph "Error Codes" - "Extra Info".
5.8.1Exit “Factory Mode”
When an "F" is displayed in the screen's right corner, this
means that the set is in "Factory" mode, and it normally
happens after a new SSB has been mounted.
To exit this mode, push the "VOLUME minus" button on the
TV's keyboard control for 5 seconds and restart the set
5.8.2 MPIF
Important things to make the MPIF work:
•Supply.
•Clock signal from the AVIP.
2
•I
C from the VIPER.
5.8.3 AVIP
Important things to make the AVIP work:
•Supplies.
•Clock signal from the VIPER.
2
C from the VIPER (error 29 and 31).
•I
5.8.4DC/DC Converter
Introduction
•The best way to find a failure in the DC/DC converters is to
check their starting-up sequence at power "on" via the
Mains/AC Power cord, presuming that the Stand-by
Processor is operational.
•If the input voltage of the DC/DC converters is around 12 V
(measured on the decoupling capacitors 2U17/2U25/
2U45) and the ENABLE signals are "low" (active), then the
output voltages should have their normal values.
•First, the Stand-by Processor activates the +1V2 supply
(via ENABLE-1V2).
•Then, after this voltage becomes present and is detected
OK (about 100 ms), the other two voltages (+2V5 and
+3V3) will be activated (via ENABLE-3V3).
•The current consumption of controller IC 7U00 is around 20
mA (that means around 200 mV drop voltage across
resistor 3U22).
•The current capability of DC/DC converters is quite high
(short-circuit current is 7 to 10 A), therefore if there is a
linear integrated stabilizer that, for example delivers 1.8V
from +3V3 with its output overloaded, the +3V3 stays
usually at its normal value even though the consumption
from +3V3 increases significantly.
•The +2V5 supply voltage is obtained via a linear stabilizer
made with discrete components that can deliver a lot of
current. Therefore, in case +2V5 (or +2V5D) is shortcircuited to GND, the +3V3 will not have the normal value
but much less.
•The supply voltage +12VSW is protected for over-currents
by fuse 1U04.
Fault Finding
•Symptom: +1V2, +2V5, and +3V3 not present (even for a
short while ~10ms).