Panasonic LH34 Technical Guide
Technical Guide
LCD High Definition TV
Models, TC-26LX20, TC-32LX20 and
Combo Model TC-22LR30
LH-34 Chassis
Functional Overview, Circuit Description and
PASC050803TG1
B19
Troubleshooting
Panasonic Services Company
National Training
A
y
Prepared by
Gerry Gaimo and Jean Magloire
Panasonic Services Company
National Training
"HDMI, the HDMI logo and High-Definition Multimedia Interface are trademarks or registered trademarks of HDMI Licensing LLC."
BBE, the BBE logo, Sonic Maximizer and High Definition Sound are registered trademarks or trademarks of BBE Sound, Inc.
Copyright © 2005 by Panasonic Services Company
ll rights reserved. Unauthorized copying and distribution is a violation of law.
Warning
This service information is designed for experienced repair technicians only and is not designed for use b
the general public. It does not contain warnings or cautions to advise non-technical individuals of potential
dangers in attempting to service a product. Products powered by electricity should be serviced or repaired
only by experienced professional technicians. Any attempt to service or repair the product or products
dealt with in this service information by anyone else could result in serious injury or death.
Table of Contents
Objective........................................................................................................................1
Features.........................................................................................................................2
LCD Technology............................................................................................................ 2
Dynamic Image Balancing............................................................................................3
3D Y/C Separation......................................................................................................... 3
LCD High Definition TV Model Differences.................................................................4
Differences between Models........................................................................................4
Circuit Board Layout.....................................................................................................5
TC-22LR30 Circuit Boards............................................................................................5
Circuit Board Interconnection...................................................................................... 6
System Control Block...................................................................................................7
A Board (TC-22LR30)....................................................................................................9
H Board (TC-26/32LX20) .............................................................................................10
K board (TC-22LR30, TC-26/32LX20)......................................................................... 11
A Board (TC-26/32LX20) .............................................................................................12
Power Supply ..............................................................................................................13
Power Supply (TC-22LR30) ........................................................................................13
P Board - Primary Power......................................................................................... 14
AP Board - Secondary Power.................................................................................15
Tuner / FIP Power Supply (AP Board)....................................................................16
Over Current Protection Shutdown Circuits .........................................................17
14-Volt Power Down Detect Circuit........................................................................18
Over Voltage Protection _ AC Shutdown Latch Circuit .......................................... 19
Power Supply (TC-26/32LX20)....................................................................................20
P board (TC-32LH, TC-26/32LX20) - Primary Power.............................................20
Standby Power Supply............................................................................................21
Primary Power Supply............................................................................................. 21
Power Supply Operation (TC-32LH, TC-26/32LX20).............................................. 22
Power On Operation of the DC-to- DC converter..................................................22
Power Off Operation of the DC-to-DC converter...................................................23
Protection of the DC-to-DC converter....................................................................23
AP Board - Secondary Power Supply ....................................................................25
Secondary Voltages...............................................................................................26
Video Circuit Explanation...........................................................................................27
A Board........................................................................................................................27
DG Board .....................................................................................................................28
Video Signal Processing ............................................................................................ 28
Video Signal Processing ............................................................................................ 29
Low Voltage Differential Signaling............................................................................30
HDMI Signal Path.........................................................................................................32
Self-Check Function for TV Section .......................................................................... 33
Self-Check Access...................................................................................................... 33
Servicing the TV Portion.............................................................................................34
Service Adjustment Mode for TV............................................................................34
How to exit Adjustment mode.................................................................................35
Servicing the DVD....................................................................................................... 36
Shutdown Problems.................................................................................................... 38
LED Flashes Three Times .....................................................................................38
LED Flashes Once every 5 seconds......................................................................39
LED Flashes Five Times........................................................................................39
LED Flashes Eight Times.......................................................................................39
Unit shuts down and the Power on LED is off........................................................39
SOS Shutdown Problem........................................................................................39
Does Not Record Video to Disc .................................................................................42
Does Not Record Audio to Disc................................................................................. 43
Primary Power Supply Check ....................................................................................44
Secondary Power Supply Check ............................................................................... 45
Appendix......................................................................................................................46
Backlighting................................................................................................................. 46
Inverter Power Supply ................................................................................................46
High Voltage Power Supply........................................................................................ 47
Test and Measurement ............................................................................................... 48
Specifications.............................................................................................................. 49
Combo Overall Specification .....................................................................................49
TV Portion....................................................................................................................50
DVD Portion.................................................................................................................51
Objective
This technical guide was prepared with the following objectives in mind:
• Provide the servicer with a brief overview of the concepts of operation for new
circuits employed in this line of models
• Provide drawings with emphasis on the signal path to simplify the task of signal
tracing and to locate the cause of a defect
• Furnish troubleshooting procedures that contribute to a expeditious repair of the
product
• Provide examples of typical problems that may have occurred in similar types of
circuits
• Provide updated information about changes reflected in the newer versions of LCD
High Definition TVs. The TC-22LR30 LCD TV /DVD Ram combo is basically a TC26/32LX20 model with the addition of a DVD Ram.
The DVD Recorder that has been incorporated in the LCD TV High Definition Combo
unit is basically the same as that of the DMR-E65.The equipment used for servicing the
DMR-E65 is same as the one used for servicing this model’s DVD-RAM Drive .The only
difference is that the DVD Recorder (DMR) has been downsized to a physically smaller
drive.
1
Features
LCD Technology
The LCD AI (Artificial Intelligence) technology incorporated within this model is very
similar to that covered in previous LCD models. The Pixel Control IC, in conjunction with
the Main Microcontroller IC, located on the DG Board, is responsible for controlling the
backlighting and the active matrix display addressing.
Backlight Brightness Control
Figure 1
Dynamically balancing the white light produced from the backlight produces a clearer
and crisper image.
Figure 2
2
Dynamic Image Balancing
Enhancements have been made in the LCD AI technology as newer units evolve. This
is an example of the improvements made in the luminance distribution in real time.
Dynamic Image Enhancement
Figure 3
3D Y/C Separation
The luminance and chrominance of the composite video signals are separated using a
three dimensional Y/C separation circuit commonly known as a Comb Filter. Dot noises
or phenomena known as dot crawl and cross colors are reduced.
Figure 4
3
LCD High Definition TV Model Differences
Differences between Models
The significant differences between models associated with the TC-22LR30 combo unit
(TC-26/32LX20 series) can be found in the following areas.
L
CD TV Section
The GC3 Global c
Microcontroller, the Video SW, and the Audio SW are same as that of the LCD TV
26/32LX20).
D
VD-RAM Section
The DVD Digital C.B
(DMR-E65). However, the software that resides in (IC6702) is different.
The equipment used for servicing the DMR-E65 is same as the one used
this model’s DVD-RAM Drive .The only difference is that the DVD Recorder (DMR) has
been downsized to a physically smaller drive.
C
ircuit Board A
The input and out
SW (IC3101).
The input and o
SW (IC3102).
The MTS/SAP
C
ircuit Board DG
The Main Micro con
incorporate communication with the DVD Recorder Circuit.
C
ircuit Board RD (Main DVD Bd.)
This Circuit Board was added to acc
ircuit Board M8 (DVD Digital Bd.)
C
This Circuit Board was added to accom
Microcontroller (IC6001) on this Board is identical to the one that resides
E65 Controller board and functions accordingly.
ircuit Board DV (HDMI Interface)
C
This Circuit Board was added to acco
(HDMI).
ircuit Board P and AP
C
The Primary (P) and Seco
the voltages required to power the DVD Recorder.
ore IC series that are used for the Video Signal processing, the
(TC-
.A. (Circuit Board M8) is the same as that of the DVD Recorder
for servicing
put signal lines for the DVD Recorder Circuit were added to the Video
utput signal lines for the DVD Recorder Circuit were added to the Audio
Audio Signal Process (IC3299) was added to record SAP to the DVD.
troller (IC1106) software was modified from the previous model to
ommodate DVD Recorder.
modate the DVD Recorder. The
mmodate the High Definition Multimedia Input
ndary Power Circuit Board (AP) were changed to incorporate
on the DMR-
4
A
A
V
Circuit Board Layout
T
C-22LR30 Circui
t Boards
The TV portion of the combo unit is very
omprised of the following boards along with their associated part numbers as shown in
c
similar to that of the TC-26/32LX20 and is
this figure. Disassembly of this unit is much easier than the disassembly of the unit
covered in the previous online course because the stand or base doesn’t have to be
removed for removing the rear cover.
Rear op
K
H
L
D
en view TC-22LR30
DG
Spk LSpk R
P
DG Board is
located under
TA
Tune
Figure 5
Board Name Par
RFKZ0214 Extension Cable
DG
A
TA
L
V
P
AP
HA
DV
K
TV Portion Circuit Board Description
t Number Description
LSEP2163AE PCB Digital Core
LSEP2164B Input/Output Switching PCB
LSEP2191A Tuner PCB
LSEP2233A Digital Audio Jack PCB
LSEP2169B Front PCB
LSEP2189A AC-DC Power PCB
LSEP2232A DC-DC Power PCB
TNPA3162AB HDMI PCB
LSEP2170B Top Operation PCB
Table 1
DVD DMRE- 65
SD Card Reader
B LSEP2199A HDMI Audio Jack PC
5
Circuit Board Interconnection
T tended to provide an overview of the interconnection o
his diagram is in f the various
circuit boards of the TC-22LR30 LCD Combo Unit.
Circuit Board Interconn
SR
ection
Board Name Part Num
RD
OP
SD
SR
M8
LSEP2171B PCB DVD MAIN
LSEP2175A DVD OPERATION PCB
LSEP2234A SD PCB
LSEP2235A SD JOINT PCB
RD-DKK005- DVD DIGITAL PCB
Figure 6
DVD Portion Circuit Board Description
ber Description
Table 2
6
System Control Block
The control signals responsible for the overall operation and control of both units are
shown in this diagram along with their designated termination points.
Main Power switch signal is derived from the power on switch, which is loca ted on
the K board. The Main Micro (TV Microcontroller), located on the DG board, sees
this as a “key scan” input signal and issues a TV ON and AC_On to the control
circuitry within the Primary and secondary power supply.
DVD Power sw itch signal is derived from the DVD operation switch, located on the
DVD OP board. This signal is responsible for initiating the power on sequence for
the DVD operation. The Main Micro sees this as a “key scan” input signal.
Panel ON signal appears on pin 28 of the DG board connector DG2. This is
equivalent to an on/off switch for the LCD Panel.
Backlight ON /OFF (B/L On/Off) signal provides the enable for the DC to AC
backlight inverter power supply which is incorporated within the LCD Panel.
OSD Timing Compensator synchronizes the OSD with the incoming video.
System Shutdow n
The Main Micro on the DG board is responsible for monitoring the various shutdown
conditions. The Main Micro monitors the SOS and main voltage (Zero X Detect)
detection signals via the DG2 connector.
LED Functions
o The Time Warp Led indicates that the DVD is recording at twice the normal
record mode (operator’s choice)
o The SD LED indicates that the SD card is being accessed either for a read or
a write operation
o The DVD LED indicates that the DVD unit is being acces sed either for a read
or a write operation
TV Data In/Out are DVD control lines used for playback and record.
DVD Play switches the audio monitor output from all audio inputs to the DVD
Output.
Wake Up provides Serial data communication between the DVD Micro and Main
Micro.
Fan Control is accomplished through the use of a fan control circuit located on the
DVD main circuit board. A PWM output signal from sub processor IC 7501 controls
the speed of the fan, based on the internal ambient temperature of the unit
7
System Control Signals
Figure 7
8
Circuit Board Description
A Board (TC-22LR30)
The A board serves as the main board and is comprised of the following:
The Video Switch IC3101 is responsible for selectively switching all video inputs
(Component, Composite, S-Video and HDMI). The selected input is fed to the
DG Board via the connector A1.
The Audio Switch (IC3102) selects the desired audio input for processing by the
Sound Control (IC2301). The MTS (IC3103) performs stereo separation of the
tuner’s multiplex signal and sends the output to the audio switch.
The TA tuner board on the TC-22LR30 provides the same functionality as the B
tuner board found on the TC26/32LX20. The output is connected to the A board
via connector PA7.
The HDMI interface, which resides on the DV board, processes and converts the
digital video and audio signals to analog and outputs them to the DG board via
the video switch.
A board TC22LR30
IC3101
IC3103
IC3102
Figure 8
9
H Board (TC-26/32LX20)
The H Board on models TC-26/32LX20 is comprised of an S - Video and Composite
video input connection, two Component video inputs, a DVI audio input and an Audio
output connection. This board has been merged onto the A board of the TC-22LR30
Combo unit.
Figure 9
10
K board (TC-22LR30, TC-26/32LX20)
The K board contains the TV ON/Off, Volume, and Channel select buttons, and an
additional S-Video and Composite video input connector and headphone jack. It
connects to the A board via connector K3.
Figure 10
11
A Board (TC-26/32LX20)
The A board for the TC-22LR30 Combo unit is very similar to that of the TC-26/32LX20
model. The H board has been merged onto this model’s A Board.
A Board TC26/32LX20
Figure 11
12
Loading...