Friday, November 20, 2015

PANASONIC PLASMA TV TH-42PX80U - TH-50PX80U - TH-42PZ80U - TH-46PZ80U- TH-50PZ80U - TH-42PZ85U - TH-46PZ85U - TH50PZ85U WORKING AND DETAILED TROUBLE SHOOTING FOR LED BLINKING ERRORS

PANASONIC TH-42PX80U - TH-50PX80U - TH-42PZ80U - TH-46PZ80U- TH-50PZ80U - TH-42PZ85U - TH-46PZ85U - TH50PZ85


PLASMA TV 

WORKING AND DETAILED TROUBLE SHOOTING FOR LED BLINKING ERRORS

WORKING AT A GLANCE
When the TV is plugged in:
AC is applied to the standby circuit in the power supply to produce STB12V and STB5V.
The STB12V is routed thru the SS board and it’s returned back to the P board to turn on a switching circuit that outputs the STB5V. If the STB5V is missing, the TV is dead (No power)
The STB5V is output from the P board at pin 5 of connector P7 and it is applied to pin 5 of connector A7 on the A board.
The STB5V is applied to a 3.3V regulator to power the Main CPU (IC1100) on the A board.
When the Main CPU (IC1100) receives 3.3V, it outputs a temporary 2.7V/3.2V command that is provided to pin 6 of connector P7 on the P board. The function of this command is to turn on the circuit that generates the “F+15V” in the P board.
The P board outputs the F+15V to pins 7, 8, and 9 of connector A7 in the A board. This voltage is applied to a regulator circuit that generates: SUB9V, SUB5V, and SUB3.V.
If any of these voltages (F+15V, SUB9V, SUB5V, and SUB3.3V) are missing, the TV shuts down and the power LED blinks 10 times.
POWER ON CIRCUIT
1. The power command from the power switch on the S board or the remote control receiver on the K board is provided to the Main CPU on the A board thru connector A1. The CPU on the A board outputs the “F_STB_ON” Command and the PANEL_STB_ON” command.
2. The “F_STB_ON” command is provided to pin 6 of connector P7 of the power supply to develop the F_STB+15V.
3. The “PANEL_STB_ON” is used to turn on the STB3.3V regulator on the A board. The output voltage is applied to the “Panel” CPU on the A board (Formerly located in the D board).
4. When the “Panel” CPU on the A board is energized, it outputs the “PANEL_MAIN_ON” Command (3.2V) to pin 11 of connector P25 on the P board. The PANEL MAIN ON command turns on the power supply circuit that outputs the Vsus, Vda, 15V, and 5V.
VOLTAGE FLOWS

EXPLODED VIEW
TH-42PZ85U

TH-42PZ85U

HOW ITS WORK
Upon connecting the Panasonic Plasma Display Television to the AC line, the sound of relays being triggered can be heard from the Power Supply board. Also a red light from the Optical jack on the back of the TV can be observed. Approximately 15 seconds later, the click sound from the relays can be heard again and the red LED inside the Optical jack turns off. This condition is normal and by paying attention to this sequence of events, we can confirm the operation of several circuits inside the TV.

When the TV is plugged in:
AC is applied to the power supply board (P) through connector P9. The AC is applied to the standby circuit to produce STB12V and STB5V. The STB5V is routed thru the SS board to turn on a circuit which function is to allow the output of the STB5V through connector P7.
The STB5V is output from the P board at pin 5 of connector P7 and it is applied to pin 5 of connector A7 on the A board.
The STB5V is applied to a 3.3V regulator to power the Main CPU (IC1100) on the A board. The 3.3V becomes STB3.3V.
The STB3.3V is applied to the power LED and the remote control receiver in the K board.
When the Main CPU (IC1100) receives 3.3V, it outputs a 2.7V command that is provided to the P board and the SOS Detect circuit within the A board. This command only lasts approximately 15 seconds and it is called “F-STB-ON”. The function of this command is to turn on the circuit that generates the “F-STB-14V” in the P board.
The function of the 2.7V command applied to the SOS Detect circuit in the A board together with the STB5V, is to activate the “SOS DETECT” circuit in the A board.
The F+15V from connector P6 on the P board is applied to connector A6 in the A board. This voltage is applied to a regulator circuit that generates: SUB9V, SUB5V, and SUB3.V.
When AC is applied to the TV, the Standby circuit outputs 5Vdc and 12Vdc. The 5V is applied to the Power CPU and a switching IC MC552 on the power supply circuit. The 5V is also provided to the SS board. A jumper at connector SS34 of the SS board routes the 5V back into the power supply board to turn on the switching circuit inside the CPU MC701. When this circuit is on, MC552 turns on and the STB5V is output to the A and D boards.
The STB5V is output to the A Boards thru pin 5 of connector P7. The STB5V is applied to a 3.3V regulator (IC4000) on the A board to provide the supply voltage (STB3.3V) to the Main CPU (IC1100).
The STB3.3V is also applied the Remote Control receiver and the power LED on the K board.
When the Main CPU IC1100 on the A board receives the 3.3V, it outputs the SUB_ON/TUNER_SUB_ON command (2.7V) to the Power MCU (MC701) located on the Power Supply board.
The power supply MCU outputs commands to turn on the circuits necessary to generate the F+15V. The F+15V from the P board is applied to the 5V/9V regulators, IC5400 and IC5401on the A board. The voltage outputs from these ICs are called SUB5V and SUB9V and are used by various circuits on the A board.
To avoid catastrophic failures, they are monitored by an SOS Detect circuit for over-voltage and overcurrent conditions.
This SOS Detect circuit is controlled by the TUNER_SUB_ON command from the Main CPU (IC1100). The SUB5V and SUB9V from IC5400 and IC5401 are connected to the CPU for voltage presence detection.
Any abnormalities of the SUB5V or SUB9V triggers the SOS circuit. The TV shuts down and the power LED blinks 10 times. This happens while the TV is off (Before turning on the power).
# The F+15V from the P board is the source that supplies the DC-DC converter (IC5400
and IC5401) in the A board. The A board outputs 9V, 5V, and 3.3V.
# The 9V is only used by the A board.
# The 5V, besides being used in the A board, is also distributed to the K and GH boards.
# The 3.3V is used in the A board and it’s also provided to the GH and GS boards.
# A 10 blinks code from the power LED indicates abnormalities on any of these voltages.
TROUBLESHOOTING 
Troubleshooting 10 blinks Condition At Plug in
These 3 conditions can cause the TV to shutdown and the power LED to blink 10 times
1.Missing/Shorted F_STB_15V
2. Missing/Shorted SUB9V, SUB5V, and SUB3.3V
3. Wrong diagnostic by the A board
Note: When taking voltage reading, place the voltmeter probe at the test point, component, or
connector’s pin indicated before connecting the TV to the AC line. This will ensure voltage reading accuracy before the TV shuts down
To troubleshoot a PDP TV that is shutting down and the power LED blinks 10 times:
Find out if 15V is output at pin 7,8,or 9 of connector P6 of the P board. If no voltage is output, the P board may be defective.
If the F_STB_15V voltage is OK, it’s likely that the A board is defective.
Since some of the Sub-voltages generated by the A board are connected to the K, GS, and
GH boards, it’s also likely that one of these board may cause the unit to shut down and the power LED to blink 10 times.
Disconnect connector A1/K1 to isolate the K board.
Disconnect connector A/52GS52 to isolate the GS board.
Disconnect connector A11/GH11 to isolate the GH board.
The defective board is found when the connector that provides the Sub-voltages to that board is removed and the TV no longer shuts down
Troubleshooting 10 blinks Condition At Power On
These 5 conditions can cause the TV to shutdown and the power LED to blink 10 times
1. Missing/Shorted F_STB_15V
2. Shorted P15V
3. Missing/Shorted SUB9V, SUB5V, and SUB3.3V
4. Missing Vda (Shorted Vda causes 5 blinks)
5. Wrong diagnostic by the A board
Note: The P15V and the F_STB_15V are created by the same circuit in the power supply circuit. A shorted P15V, normally causes the TV to shut down and the power LED to blink 2 times. Sometimes a shorted P15V affects the F_STB_15V and this causes the TV to shutdown making the power LED blink 10 times.
To troubleshoot a PDP TV that is shutting down and the power LED blinks 10 times:
Isolate the SC and the SS boards (They may cause a 10 blinks shutdown). Disconnecting P6
and P7 allows for only the panel drive section to be driven. If the LED on the SS board and
the LED on the SC board are lid, then the SS and the SC boards are OK and the A board is
suspected to be defective
If the LEDs on the SS and SC boards are not lid, then isolate them one at time.
If the SS and SC boards are OK, then the P board may be defective.
POWER LED BLINKING 
Number of blink
Contents
Check point
1
Communication Error with Microcomputer
D, A
2
15V SOS
D
3
3.3V SOS
D
4
Power Supply SOS
P
5
5V SOS
D
6
SC Energy recovery SOS
SC, SU, SD, D, P
7
SC floating voltage SOS
SC, SU, SD, D, P
8
SS Energy recovery SOS
SS, D, P
9
Panel Configuration SOS
D
10
Sub 5V SOS, Main 3.3V SOS, DTV9V SOS, Tuner SOS
A
12
Sound SOS
A
13
Communication Error with Peaks Lite-2
A

D BOARD SOS DETECT 
# Protection circuits are incorporated in the unit to prevent the failure of a single circuit or component from creating catastrophic damage.
# A shutdown condition occurs when there is an over voltage, a short or a drop in any of the voltage lines. Also the shutdown circuit is triggered when the fans are drawing more current than normal.
# Normally the CPU of the D board and the CPU of the A board detect when a shutdown condition has been triggered.
# When an abnormality has occurred, the unit protection circuit operates and the TV is reset to the stand-by mode. At this time, the defective block can be identified by the number of blinks of the POWER LED on the front of the unit.
# IC9003 of the D board detects conditions that make the power LED blinks 2, 3, 4, 5,
6, 7, 8, or 9 times.
# The following table identifies the areas where a problem is suspected according to the number of times that the POWER LED blinks.
2 Blinks SOS: Pin 62 of the CPU IC9003 monitors the 15V line. During normal operation pin 62 is kept high. If the 15V line is missing or shorted, a low is provided to pin 62. As a result, the unit shuts down and the power LED blinks 2 times.
3 Blinks SOS: IC9805 is a 3.3V regulator located on the D board. Its output is monitored by IC9003. If the 3.3V is not present at pin 61, the CPU (IC9003) shuts down the unit. The power LED blinks 3 times.
4 Blinks SOS: When an over voltage condition of the voltage lines from the power supply occurs, pin 18 of MC701 goes high. This high is provided to pin 67 of IC9003 of the D board triggering the “POWER SOS” circuit. When this happens, the TV shuts down and the power LED blinks 4 times. Primarily the P board causes 4 blinks, followed by the D board.
5 Blinks SOS: Pin 60 of the CPU IC9003 monitors the 5V line. During normal operation, pin 60 is kept high. If the 5V line is missing or shorted, a low is provided to pin 60. As a result, the unit shuts down and the power LED blinks 5 times.
6 Blinks SOS: Pin 65 of the CPU IC9003 monitors the status of the SC board. During normal operation, a low is applied to pin 65. If the SC board becomes defective, a high is provided to pin 65. As a result, the unit shuts down and the power LED blinks 6 times.
7 Blinks SOS: Pin 68 of the CPU IC9003 monitors the status of the SC, SU, SD board. During normal operation, a low is applied to pin 76. If the SC, SU, or SD board becomes defective, a high is provided to pin 68. As a result, the unit shuts down and the power LED blinks 7 times.
8 Blinks SOS: Pin 66 of the MPU IC9003 monitors the status of the SS board. During normal operation, pin 8 of connector SS33 outputs a low to pin 66. If the SS board becomes defective, a high is provided to pin 66. As a result, the unit shuts down and the power LED blinks 8 times.
ERROR CODE TROUBLESHOOTING IN DETAIL 
2 Blinks Error Code
These 3 conditions can cause the TV to shutdown and the power LED to blink 2 times
1. Missing P15V
2. A short of the P15V
3. Wrong diagnostic by the D board
Troubleshooting 2 Blinks
When troubleshooting a PDP TV that is shutting down and the power LED blinks 2 times:
Find out if 15V is output at pin 1 of connector P7 of the P board. If no voltage is output, measure resistance between pin 1 of connector P7 and ground (Chassis). If a shorted 15V is detected, find out if it’s coming from the P board or if it’s coming from any of the other boards that the 15V volt is connected to.
If the P board is OK, disconnect the connectors providing the P15V to all these boards while measuring resistance between pin 1 of connector P7 and ground.
The defective board is found when the connector that provides the P15V to that board is removed and the short circuit is no-longer present.
5 Blinks Error
These 4 conditions can cause the TV to shutdown and the power LED to blink 2 times
1. Missing P5V
2. A short of the P5V
3. A short of the Vda line (Note: missing Vda from the P board does not cause 5 blinks)
4. Wrong diagnostic by the D board
Troubleshooting 5 Blinks
When troubleshooting a PDP TV that is shutting down and the power LED blinks 5 times:
Find out if pin 1 of connector P12 is shorted to ground. If it is, possibly the panel is bad. If there is no short circuit, proceed to check the P5V line. Find out if 5V is output at pin 5 of connector P25 of the P board. If no voltage is output, measure resistance between pin 5 of connector P25 and ground (Chassis). If a shorted 5V is detected, find out if it’s created on the P board or if it’s created on any of the other boards that the 5V volt is connected to.
If the P board is OK, disconnect the connectors providing the P5V to all these boards while measuring resistance between pin 5 of connector P25 and ground.
The defective board is found when the connector that provides the P15V to that board is removed and the short circuit is no-longer present.
8 Blinks SOS Detect
There is an extra SOS Detect circuit in the Sustain board. This circuit is Mused to monitors for short circuit condition of the sustain electrodes in the panel.
Under normal condition, D16282 conducts keeping Q16280 on. When Q16280 is on, a low is provided to the anode of D16280 (D280). If a short circuit is detected, Q16280 turns off and a high is provided to the anode of D16280 (D280). This high is provided to pin 66 of the CPU in the D board. When this happens, the TV shuts down and the power LED blinks 8 times.
To determine if the 8 blinks is caused by the D board, SS board, or the
Panel:

# Isolate the SS board and check if the TV stays on when it’s turned on.
# If the TV does not stay on after disconnecting the SS board, the D board is defective.
# If the TV stays on, then the SS or the Panel is defective.
# If the anode of D16280 (D280) is high (2.7V) at the time the unit shuts down, the Panel is defective.
# If the anode is low, the SS board is defective
Symptoms caused by defective SD boards

These symptom seems to be caused by a defective D or SC board but in reality, they are caused by a defective SD board. To confirm this, disconnect the SD board from the SC board

If the SD is defective, the screen will have a good picture at the top half of the screen and a completely black area in the lower half.
10 Blinks SOS: The voltage regulators IC5400 and IC5401 in the A board generate SUB9V and SUB5V. The 9V and 5V from these ICs are monitored by IC1100. Any abnormality on the SUB9V or SUB5V lines, triggers the shutdown circuit and the MPU shuts down the unit. The power LED blinks 10 times.
11 Blinks SOS: The ventilation fans are monitored for proper operation. If one of the fans opens or increases resistance, the resulting current change is applied to pin 61 of the main CPU. This triggers the Fan SOS and the TV shuts down. The power LED blinks 11 times. To prevent the TV from shutting down when one of the fans is disconnected, a jumper should be placed between pin 2 and pin 3 of the missing fan connector.
12 Blinks SOS: On the A board, transistor Q2301 monitors the Sound 15V line and the operation of the audio power amplifier IC2301. If the audio output circuit, IC2301, or the 15V lines develops a short to ground, transistor Q2301 goes into conduction and applies a high to pin 70 of the MPU, IC1100, triggering a SOS condition. The power LED blinks 12 times. A short circuit in the sound P15V normally shuts the TV down and the power LED blinks 2 times. It can also cause the TV to shutdown and make the power LED blink 12 times.