Grundig Montreal26 and Grundig Xentia26, 26 inch LCD TV SMPS and display driver schematic

Used ICs: FA5501N, MP1583, SI4925, F9222L, M385

Grundig XENTIA 26 - LW 68-7410 TOP
GBB9600

Grundig MONTREAL 26 - LW 68-7472 TOP

GBB9500

Display Driver schematic [M385]

SMPS schematic [ FA5501N - MP1583 - SI4925 - F9222L ]

Aiwa NSX D9, Aiwa NSX T9 compact disc stereo cassette receiver circuit diagram

Used ICs: BA3880FS, BU9262AFS, M62445FP, BU4551BF, BA7762AFS, CXA1553P, M62449FP, BA3835F, BU2099, BU9990-03F5, LC876580-5K75 / LC76580-5K6(VCB), M65847AFP

Schematic [Click on the schematics to zoom in]

BA3880FS, BU9262AFS, M62445FP, BU4551BF

 BA7762AFS, CXA1553P 

M62449FP

BA3835F, BU2099, BU9990-03F5, LC876580-5K75 / LC76580-5K6(VCB)

M65847AFP

PN51E490 B4FXZA Samsung plasma TV troubleshooting

Power Supply Trouble Shooting

VITAL SIGNS check Vs, Va, Vsc & Ve When troubleshooting, It’s very important to first check Vs, Va, Vsc & Ve

If Vs is missing (0V), disconnect power and check for short. Use ohm meter to measure resistance while disconnecting Y/X-Board supply feed.

* Turn Power On and Test SMPS with short connector removed for correct Vs voltage verification. (It may only come up briefly but to full level). Again be careful not to reconnect Power Connectors until Vs falls below 10V

* If Va is low or missing, disconnect Supply Feed to Logic Buffer Boards and check to see if SMPS Supply is restored.

* If Vsc is low or missing and Vs was OK, the failure is with the Y/XBoard since the Y-Board section generates the Vsc voltage from the Vs supplied by the SMPS.

* If Ve is low or missing and Vs is OK, the failure is with the Y/X-Board since the Ve is generated by the X-Board section from the Vs supplied by the SMPS.

Other SMPS Voltages:
Check Low Voltage feeds to the Main Board and other supplied Assemblies.

Over Current Protection

For the SMPS Power Supply... If a short circuit occurs on either the VS or VA voltage lines, the SMPS stops operating, but should not fail. When the short circuit is removed from the source line, the Power Supply will operate normally again. Many SMPS Supplies are replaced needlessly.

2010/2011/2012 models

Will not be run when the “X“ or “Y” or “Y/X” Main are disconnected. The SMPS will shut down immediately. However if a meter is first connected to the test point when power is applied it will read the correct voltage briefly before shutting down.(You have enough time to check key voltages)

CAUTION: Do not reconnect any connectors to SMPS or Y/X Board(s) until power has been turned off long enough for Vs to drop below 10V or damage will occur to X/ Y Board(s).

Activating power and logic board test pattern without main board.

* Remove power cord to panel.

* Short Highest 2 pins# on Logic Board.  Test jig (can be 4 pin or 6 pin)

* Remove power connector at main board [keeping connection to [SMPS]

* Short “Power On” pin to circuit Ground on power connector to SMPS.

* Connect the power cord to panel.

Click on the pictures to magnify

Function Control Troubleshooting

5 directional function controls [UNEH4000 sample]

Standby A3.3V on Function Connector, Pin 3.

All Pins should read 3.3V before commands.

Press, at Key 1, Pin 6. 3.3V to 0.0V DC

Left, Right, Up, Down at Key 2, Pin 7.  Check specific voltages on chart.

All functions can be tested in Standby Mode.

VIDEO PROBLEMS

Verify Video Operation:
A. Customer Picture Test
B. “Display”
C. If display & Customer Picture Test are OK source is suspected
D. Substitute with known good source and cabling.

Using Test Patterns in Service Mode:
Customer Remote
A. Power off
B. Mute, 182, Power
Factory Remote:
A. Power On
B. Info, Test.

Verify M-STAR Patterns
4. Verify Logic Patterns

If Logic Patterns are OK and MStar are noisy, replace the defective LVDS Cable or Main Board.
If M-Star and Logic Patterns are both noisy check for specific on screen noise error to determine failure.

ON SCREEN FAILURE EXAMPLES:

NOTE: X/Y MAIN Combined.

ALIGNMENTS

Check/Adj. VS, VA, VE, & VSC according to Panel Label and Diffusion test.

DIFFUSION TEST/ADJ. (cell miss-firing)
- Allow the unit to warm up 15 to 20 minutes
- Access the Burn Protect Sig. Pattern in Cust. Menu.
-Adjust the Vs volts until screen errors are gone in both dark and bright areas.
-Adjust the Vs volts within +/- 10V on the panel label.
-NOTE: Diffusion may appear with aging panels.
New panels with Diffusion report problem.

Check/Set Option Bytes:

E490 Supply Adjustments

E490 Power on sequence

Magnavox MWC24T5 Service mode and adjustments, SMPS circuit diagram - 24 inch COLOR CRT-TV/DVD/VCR

How to enter service mode, adjustments, Power supply regulator board circuit diagram, Magnavox MWC24T5 24 inch COLOR TV/DVD/VCR, Universal remote control set-up code list for Magnavox brand TVs

When servicing the deck mechanism, refer to MK14 Deck Mechanism.

Deck Mechanism Part No.: N2466FT

The MWC24T5 version B model, which is different from the previous model. For MWC24T5 version B model, a suffix “B” is printed on the rating label on the back of the unit. Refer to the rating label illustration.

How to make service remote control unit:

Prepare normal remote control unit

 (Part No. NE204UD or NE209UD).
* Remove 4 screws from the back lid.
* Remove the batteries.
* Cut off pin 10 of the remote control microprocessor and short circuit pins 10 and 17 of the microprocessor with a jumper wire.
* Insert the battery.  

The user remote control is now act as service remote control.  

After all service adjustments,  and making the set to normal mode,remove the battery again, and remove the short short circuit, re-solder the pin 10 to the circuit board.  

Insert the battery again, close the remote control. 

Now the remote control has turned to user remote control again.

How to enter the Service mode:
1. Use the service remote control unit.
2. Turn the power on. (Use main power on the TV unit.)
3. To enter the TV mode, press [CH.Up/Dn] buttons on the TV unit.
4. Press [DISC MENU] button on the service remote control unit. 

(Version of micro computer will display on the CRT. (Ex: BA4-0.16).)

X-Ray Protection Test
X-Ray protection test should be done when replacing any parts of this chassis.
1. Short both ends of R2592 (on Sub CBA).
2. Confirm that the main power turns off.
3. If the main power does not turn off, then replace the following parts (D2591, Q2591, R2592, R2593, R2594 and IC1201).
4. Perform steps 1 to 3 again.

Setting for CONTRAST, COLOR,TINT, V-TINT and SHARP Data Values

1. Enter the Service mode. 

2. Press [PICTURE] button on the service remote control unit. 

Display changes “BRT,” “CNT,” “COL,” “TNT,” “V-T,” and “SHP” cyclically when [PICTURE] button is pressed.

CONTRAST (CNT)
1. Press [PICTURE] button on the service remote control unit. Then select “CONTRAST (CNT)” display.
2. Press [CH.Up/Dn] buttons on the service remote control unit so that the value of “CONTRAST (CNT)” becomes 84.

COLOR (COL)
1. Press [PICTURE] button on the service remote control unit. Then select “COLOR (COL)” display.
2. Press [CH. Up/Dn] buttons on the service remote control unit so that the value of “COLOR (COL)” becomes 58.

TINT (TNT)
1. Press [PICTURE] button on the service remote control unit. Then select “TINT (TNT)” display.
2. Press [CH.Up/Dn] buttons on the service remote control unit so that the value of “TINT (TNT)” becomes 45.

V-TINT (V-T)
1. Press [PICTURE] button on the service remote control unit. Then select “V-TINT (V-T)” display.
2. Press [CH.Up/Dn] buttons on the service remote control unit so that the value of “V-TINT (V-T)” becomes 49.

SHARP (SHP)
1. Press [PICTURE] button on the service remote control unit. Then select “SHARP (SHP)” display.
2. Press [CH.Up/Dn] buttons on the service remote control unit so that the value of “SHARP (SHP)” becomes 46.
Note: BRIGHT data value does not need to be adjusted because this setting is performed in other setting.

H f0 Adjustment

Purpose: To get correct horizontal position and size of screen image.

Symptom of Misadjustment: Horizontal position and size of screen image may not be properly displayed.

1. Connect frequency counter to R2583.

2. Operate the unit for at least 20 minutes.

3. Enter the Service mode.  Press [2] button on the remote control unit and select HADJ mode.

4. Press [CH.Up/Dn] buttons on the remote control unit so that the display will change “0” to “7.”

5. At this moment, choose display “0” to “7” when the frequency counter display is closest to 15.734 kHz 300 Hz.

Cut-off Adjustment
Purpose: To adjust the beam current of R, G, B, and screen voltage.
Symptom of Misadjustment: White color may be reddish, greenish or bluish.

1. Degauss the CRT and allow the unit to operate for 20 minutes before starting the alignment.
2. Input the Black raster signal from RF input.
3. Enter the Service mode.

4. Press the [VOL Dn] button.  (Press [VOL Dn] button then display will change “C/D”, “7F” and Initial Setting.)
5. Choose CUT OFF/DRIVE mode then press [1] button. This adjustment mode is CUT OFF (R).
6. Increase the screen control so that the horizontal line just appears on the CRT.
7. Press the [CH. Up/Dn] buttons until the horizontal line becomes white.
8. Choose CUT OFF/DRIVE mode then press [2] button. This adjustment mode is CUT OFF (G).
Press [CH.Up/Dn] buttons until the horizontal line becomes white.
9. Choose CUT OFF/DRIVE mode then press [3] button. This adjustment mode is CUT OFF (B).
Press [CH. Up/Dn] buttons until the horizontal line becomes white.

H. Size Adjustment

Purpose: To obtain correct size of screen image.

Symptom of Misadjustment: Size of screen image may not be properly displayed.

Note: VR2531 --- Sub CBA

1. Input monoscope pattern.

2. Adjust VR2531 so that the monoscope pattern is 90+1%/-5% of display size and the circle is round.

H. Pincushion Adjustment

Purpose: To obtain straight line on the screen.

Symptom of Misadjustment: Straight line image may not be properly displayed.

Note: VR2530 --- Sub CBA

1. Input crosshatch pattern.

2. Adjust VR2530 so that the lines of the crosshatch pattern become straight.

White Balance Adjustment
Purpose: To mix red, green and blue beams correctly for pure white.
Symptom of Misadjustment: White becomes bluish or reddish.

Note: Use service remote control unit
1. Operate the unit more than 20 minutes.
2. Face the unit to the east. Degauss the CRT using a degaussing coil.
3. Input the White Raster (APL 100%).
4. Set the color analyzer to the CHROMA mode and after zero point calibration; bring the optical receptor to the center on the tube surface (CRT).
5. Enter the Service mode. Press [VOL Dn] button on the service remote control unit and select “C/D” mode. (Display changes “C/D”, “7F” and Initial Setting cyclically when [VOL Dn] button is pressed.)
6. Press [4] button on the service remote control unit for Red adjustment. Press [5] button on the service remote control unit for Blue adjustment.
7. In each color mode, press [CH. Up/Dn] buttons to adjust the values of color.
8. Adjust Red and Blue color so that the temperature becomes 9200K (x: 286 / y: 294) ±3%.
9. At this time, re-check that horizontal line is white. If not, re-adjust Cut-off Adjustment until the horizontal line becomes pure white.
10. Turn off and on again to return to normal mode.  Receive APL 100% white signal and confirm that Chroma temperatures become 9200K (x: 286 / y:294) ±3%.
Note: Confirm that Cut Off Adj. is correct after this adjustment, and attempt Cut Off Adj. if needed.

Sub-Brightness Adjustment
Purpose: To get proper brightness.
Symptom of Misadjustment: If Sub-Brightness is incorrect, proper brightness cannot be obtained by adjusting the Brightness Control.

Note: SMPTE Setup level --- 7.5 IRE
1. Enter the Service mode. Then input SMPTE signal from RF input.
2. Press [PICTURE] button. (Press [PICTURE] button then display will change BRT, CNT, COL, TNT, V-T, and SHP). Select BRT and press [CH. Up/Dn] buttons so that the bar is just visible.

Focus Adjustment
Purpose: Set the optimum Focus.
Symptom of Misadjustment: If Focus Adjustment is incorrect, blurred images are shown on the display.

Note: Focus VR --- FBT (Sub CBA),
FBT = Fly Back Transformer
1. Operate the unit more than 30 minutes.
2. Face the unit to the East and degauss the CRT using a degaussing coil.
3. Input the monoscope pattern.
4. Adjust the Focus Control on the FBT to obtain a clear picture.

H. Position Adjustment
Purpose: To obtain correct horizontal position of screen image.
Symptom of Misadjustment: H. position may not be properly displayed.

1. Enter the Service mode.
Press [8] button on the remote control unit and select H-P mode.
2. Input monoscope pattern.
3. Press [CH.Up/Dn] buttons on the remote control unit so that the left and right side of the monoscope pattern are equal to each other.

V. Shift Adjustment
Purpose: To obtain correct vertical position of screen image.
Symptom of Misadjustment: If V. position is incorrect, vertical position of image on the screen may not be properly displayed.

1. Enter the Service mode.
Press [9] button on the remote control unit and select V-P mode. (Press [9] button then display will change to V-P and V-S).
2. Input monoscope pattern.
3. Press [CH.Up/Dn] buttons on the remote control unit so that the top and bottom of the monoscope pattern are equal to each other.

V. Size Adjustment
Purpose: To obtain correct vertical height of screen image.
Symptom of Misadjustment: If V. Size is incorrect, vertical height of image on the screen may not be properly displayed.

1. Enter the Service mode.
Press [9] button on the remote control unit and select V-S mode. (Press [9] button then display will change to V-P and V-S).
2. Input monoscope pattern.
3. Press [CH. Up/Dn] buttons on the remote control unit so that the monoscope pattern is 905% of display size and the circle is round.

Head Switching Position Adjustment
Purpose: Determine the Head Switching Position during Playback.
Symptom of Misadjustment: May cause Head Switching Noise or Vertical Jitter in the picture.
Note: Unit reads Head Switching Position automatically and displays it on the screen (Upper Left Corner).
1. Playback test tape (VFMS0001H6).
2. Enter the Service mode.
Then press the number [5] button on the remote control unit.
3. The Head switching position will display on the screen; if adjustment is necessary follow step 4.
6.5H(412.7microseconds) is preferable.
4. Press [CH.Up] or [CH.Dn] button on the remote control unit if necessary. The value will be changed in 0.5H steps up or down. Adjustable range is up to 9.5H. If the value is beyond
adjustable range, the display will change as:
Lower out of range: 0.0H
Upper out of range: -.-H

The following 2 adjustments normally are not attempted in the field. They should be done only when replacing the CRT then adjust as a preparation.

Purity Adjustment

Purpose: To obtain pure color.

Symptom of Misadjustment: If Color Purity Adjustment is incorrect, large areas of color may not be properly displayed.

* This becomes RED COLOR if the [7] button is pressed while in service mode.

1. Set the unit facing east.

2. Operate the unit for over 30 minutes before adjusting.

3. Fully degauss the unit using an external degaussing coil.

4. Set the unit to the AUX mode which is located before CH2 then input a red raster from video in.

5. Loosen the screw on the Deflection Yoke Clamper and pull the Deflection Yoke back away from the screen.

6. Loosen the Ring Lock and adjust the Purity Magnets so that a red field is obtained at the center of the screen. Tighten Ring Lock. 

7. Slowly push the Deflection Yoke toward the bell of the CRT and set it where a uniform red field is obtained.

8. Tighten the clamp screw on the Deflection Yoke.

Convergence Adjustment
Purpose: To obtain proper convergence of red, green and blue beams.
Symptom of Misadjustment: If Convergence Adjustment is incorrect, the edge of white letters may have color edges.

1. Set the unit to the AUX mode which is located before CH2 then input a dot or crosshatch pattern.
2. Loosen the Ring Lock and align red with blue dots or crosshatch at the center of the screen by rotating (RB) C.P. Magnets.
3. Align red / blue with green dots at the center of the screen by rotating (RB-G) C.P. Magnet.

4. Fix the C.P. Magnets by tightening the Ring Lock.
5. Remove the DY Wedges and slightly tilt the Deflection Yoke horizontally and vertically to obtain the best overall convergence.
6. Fix the Deflection Yoke by carefully inserting the DY Wedges between CRT and Deflection Yoke.

HOW TO INITIALIZE THE TV/DVD/VCR

To put the program back at the factory-default, initialize the TV/DVD/VCR as the following procedure.

 DVD Section
1. Turn the power on and press [SELECT] button on the remote control unit to put the TV/DVD/VCR into DVD mode.
2. Press [1], [2], [3], [4], and [DISPLAY] buttons on the remote control unit in that order.
3. Press [CLEAR] button on the remote control unit.

When “OK” appears on the screen, the factory default will be set.
4. To exit this mode, press [CH. Up/Dn] or [SELECT] button to go to TV mode, or press [STANDBY-ON] button to turn the power off.

TV/VCR Section 

1. Use the service remote control unit.

2. Turn the power on. (Use main power on the TV unit.)

3. Press [DISC MENU] button on the service remote control unit to enter the Service mode.

4. Press [VOL Dn] button on the service remote control unit twice, and confirm that OSD indication is “7F = FF.” If needed, set it to become “7F = FF” by pressing [CH.Up/Dn] buttons on the service remote control unit.

5. Confirm that OSD indication on the four corners on TV screen changes from on and off light indication to red by pressing a [DISPLAY] button.  (It is necessary for one or two seconds.)

6. Turn the power off by pressing main power button on the TV unit, and unplug the AC cord from the AC outlet.

FIRMWARE RENEWAL MODE

1. Turn the power on and press [SELECT] button on the remote control unit to put the TV/DVD/VCR into DVD mode. Then remove the disc on the tray.
(It is possible to move to F/W version up mode only when the TV/DVD/VCR is in DVD mode with the tray open.)
2. To put the TV/DVD/VCR into F/W version up mode, press [9], [8], [7], [6], and [MODE] buttons on the remote control unit in that order.

The TV/DVD/VCR can also enter the version up mode with the tray open. In this case, Fig.  will be shown on the screen while the tray is open.
3. Load the disc for version up.
4. The TV/DVD/VCR enters the F/W version up mode automatically. Fig. appears on the screen.
If you enter the F/W for different models, “Disc Error” will appear on the screen, and then the tray will open automatically.

5. After programming is finished, the tray opens automatically. And the checksum will be shown.

At this time, no button is available.

6. Remove the disc on the tray.

7. Press [SELECT] button on the remote control unit to go to TV mode, or press [STANDBY-ON] button on the unit to turn the power off.

8. Press [SELECT] button on the remote control unit to put the TV/DVD/VCR into DVD mode again.

9. Press [1], [2], [3], [4], and [DISPLAY] buttons on the remote control unit in that order.

10. Press [CLEAR] button on the remote control unit.

When “OK” appears on the screen, the factory default will be set. Then the firmware renewal mode is complete.
11. To exit this mode, press [CH. Up/Dn] or [SELECT] button to go to TV mode, or press [STANDBY-ON] button to turn the power off.

SMPS circuit diagram

CAUTION:

Fixed Voltage (or Auto voltage selectable) power supply circuit is used in this unit.
If Main Fuse (F1601) is blown, first check to see that all components in the power supply circuit are not defective before you connect the AC plug to the AC power supply. Otherwise it may cause some components in the power supply circuit to fail.

Universal remote control set-up codes to check with Magnavox Brand Televisions

0018 0042 0049 0101 0152 0680

Electro help - Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

Samsung Plasma TV – Working principle and troubleshooting procedure

Function Description by board  
SMPS(Switching Mode Power Supply)
: It is the supplier to provide voltage and current to work the drive voltage and panel in each board.
X-MAIN BOARD
: It makes the drive wave form by switching FETs to Timing Controlle coming from logic-board and
supplies X electrode of panel with the drive wave form via connector.
Y-MAIN BOARD
: It makes the drive wave form by switching FETs to Timing Controller coming from the logic-board and provides Y electrode of panel with the drive wave form via Scan Driver IC on Y buffer board in order.
LOGIC MAIN BOARD
: It process image signal and performs buffering of the logic-main board (to create XY drive signal and output) and the address driver output signal.  Then it supplies the output signal to the address driver IC(COF Module).

LOGIC BUFFER(E,F,G) 

: It delivers the data signal and control signal to the COF.
Y-BUFFER (Upper,Lower)
: It is the board to impress the scan waveform on the Y board and consist of 2 boards (upper board and lower board).
8 Y-buffers are fixed at the scan driver (STV7617 of STC corp. : 64 or 65 Output).
AC Noise Filter
: It has functions to remove noise(low frequency) coming from AC LINE and prevent surge.  It gives serious effects on the safety regulations (EMC, EMI) according to AC filter.
COF(Chip on Flexible)
: It impress the Va pulse to the address electrode in the address section and forms the address discharge by electric potential difference with scanning pulse to be dismissed by the Y electrode.  It is made in the form of COF and one COF consists of 4 Data Drive IC (STV7610A :96 Output), otherwise single scan is made of 7 COF

Operation Description on SMPS
1. Overview
SMPS used in PDP 42" developed into the compact-sized with high efficiency.  The asymmetrical half bridge and the fly-back converter are applied into all output. To comply with the harmonic restrictions, it takes the power factor improvement circuit, which converts AC into the high DC and uses as the input of another converter controller.
2. Input controller
SMPS works in whole section of AC 90~264V. It is possible to start in the AC 90 and can restart with new input voltage, even in interruption of electric power. STD_5V comes out when AC is impressed
3. Output Controller
Given SMPS have 15 output voltages. The following shows the specification of output voltage and output current in case of their successive drive.

Click on the pictures to zoom in

Over-voltage protection

It has circuit to maintain normal voltage, additionally with circuit for sensing overvoltage, so it means any overvoltage does not give impacts on other output controller. SMPS prevents overvoltage in the latch mode.  VS(85V) works protection function more than 100V, over 94V for VA(75V), over 8.2V for D6V, over 4.7V for D3.3V

Short circuit and over-voltage protection

It forms definition that in the short circuit of output controller the output impedance is lower than 300mohm. If the VS output have a short circuit in case of given SMPS, SMPS stops its working.  Even in the case of short circuit between main output and STD_5V, SMPS does not break down.

When the short circuit is removed, it restarts

AC-DC Converter

It converts AC into DC by using the power factor improvement circuit. This converter was designated to control the high frequency noise, with the function to improve the power factor. This part becomes input controller of another constant-voltage.

Auxiliary Power
It is the part to supply power of mycom for remote control. When the power is on, it will work, which means that MICOM is on standby.  This output part is standby voltage. When the power-on signal from remote control impress, it works main power panel of SMPS via standby voltage.

Configuration of VS output
Major part of PDF SMPS outputs 85V 5A. It takes asymmetrical half bridge converter and connects 2 converters with 85V output in parallel, which increases efficiency than one 85V converter, on the other hand, decreases its size.

PWM Part
It uses PWM part of ML4824, but there are some points to take cautions. As this part is synchronized with the PFC part, PWM wave in the current mode drive is induced via the current sensor resistance or current transformer, and shows the current flowing in the output controller.

Operation Explanation of Driving Circuit
1. Overview of Driver Circuit
1) Definition of Driver Circuit
The driver circuit division drives the panel with the proper wave form (high voltage pulse) to develop image on the outside terminal division (X electrode group, Y electrode group, Address electrode).  High voltage switching pulse is made by MOSFET combination.
2) Working Principle of Driver Circuit
To develop image on the PDP, the voltage should be impressed into the X, Y and ADDRESS electrodes (which are component of each pictorial element) under the proper conditions. The driver wave form which is currently applied to is ADS (Address & Display Separate: Driving method to work by dividing address and constant-current section ) Based on this method, the discharge to be done in the pictorial element of PDP can be divided into 3 types as follows.

Address Discharge: to form the wall voltage within pictorial element by providing lighting pictorial element with information(impressing data voltage)
: It is the discharge produced by difference between the positive electric potential of address electrode (normally, Va impressed voltage of 70~75V +Positive Wall charge) and negative electric potential of Y electrode (GND level impression+ Negative Wall charge) 

Constant-current Discharge: 

It is the display section to form discharge voluntarily with the help of wall voltage formed by address discharge. (It makes optical power to create image)
: It is the Self Sustaining Discharge made by combining the electric potential of coherent pulse, normally 160-170Volt, which alternates the X electrode with Y electrode in the sustain section, with the wall voltage according to the pictorial element condition changed by if the former discharge exists or not. That is to say, it works according to Memory characteristic (it means that former working condition defines the current condition) as the basic feature of AC PDP.
If the wall voltage formerly exists in the pictorial element (i.e., the pictorial element is on), the discharge makes forms again because the voltage higher than one of the discharging starting time is impressed by combination of the wall voltage and of the next impressed constant-current.  While if the wall voltage does not exist in the pictorial element (i.e., the pictorial element is off), the discharge does not form because the voltage could not reach to the level of the discharging starting time, only with constant-current.

Erasing discharge: 

To selectively perform the address discharge for respective pixel, pixels of all panels must be on same conditions (same wall charge state and space charge state).  Therefore the erasing discharge zone is important factor to obtain driving margins.

There are various methods such as application of log waveform but the wall voltage control method by the Ramp Waveform is now widely applied.

: The purpose of initialization (Erasing) discharge is to make wall voltage within the the whole of Pixels.  In other words, the erasing discharge must make difference between wall voltages uniform depending on whether or not the sustain discharge exists in the previous state. Namely it must remove the wall voltage formed by the sustain discharge and supply ions or elements by causing discharge for removing the wall voltage. In the other words, To remove the wall voltage, limit the time when polarity of the wall voltage is reversely charged by causing discharge or prevent polarity form being reversely charged by supplying appropriate quantity of ions or elements through forming weak discharge [low voltage of erasing].  There are two types of the weak discharge [low voltage]as known so far. 

1) Log Waveform adopted by the F-company 

2) Weak erasing discharge by the Ramp Waveform largely adopted by Matsushita Company, etc. Outside applied voltage is adjusted depending on difference of wall voltage within Pixel, since discharge is formed when the sum of the existing wall voltage remained and the voltage on a rising waveform exceed the driving beginning voltage, by slowly applying the rising slope of the erased waveform for these two methods. In addition, weak discharge is formed since the strength of applied voltage is small.

Essential factors for driving board operation

- Supplied from power board and the optimum value may somewhat differ from the below cases.

● Vs : 85V - Sustain

● Vset : 60V ~ 70V - Y Rising Ramp

● Ve : 110V - Ve bias

● Vscan : 70V ~ 80V - Scan bias

● Vdd : 3.3V - Logic signal buffer IC

● Vcc : 15V - FET Gate drive IC

● Logic Signal

: Supplied from logic board

: Gate signal of each FET

Explanation of Function per Pulse

● Y Rising Ramp Pulse

Outside voltage of about 390V~400V is applied to the Y electrode in the Y Rising Ramp zone, and weak discharge begins if respective gap voltage equals to the discharge beginning voltage.  Negative Wall charges accumulate on the Y electrode and the Positive Wall charges on the X electrode in the whole while weak discharge is maintained.

● Y Falling Ramp Pulse

Most of Negative Wall charges accumulated on the Y electrode by the X bias of about 200V are used to remove Positive Wall charges in the Y Falling Ramp zone, and most of Positive charges accumulated on the (0V) Rising Ramp zone toward the address electrode are maintained, having distribution of wall charges beneficial for the subsequent address discharge

Y Scan Pulse

Y scan pulse is called as injection pulse, and selects the Y electrode one by one (Line-at-a-time).  In this case, Vscan is called as Scan bias. For the electrode line with the Vscan voltage applied, voltage of about 70 Volt (Vscan) is applied, and voltage of 0 Volt(GN0) is applied.  However, since Negative Wall charges accumulate on the Y electrode by the application of Ramp pulse and Positive Wall charges accumulate on the address electrode, voltage of more than the discharge beginning voltage is applied to the cell where address pulse(70V~75V) is allotted and thus address discharge occurs. Address time of the PDP is very long since both scan pulse and data pulse must be applied in line at a time.

● 1st Sustain Pulse

The Sustain Pulse always begins from the Y electrode, it is because Positive Wall charges are formed on the Y electrode if address discharge occurs. The wall charges formed by the address discharge are less than those for the sustain discharge, and thus the strength of the initial discharge is weak.  Sustain discharge usually become stable after 5~6 times of discharge depending on structure of electrode and environment. Therefore, the initial long sustain pulse is intended to form the initial discharge stable and form the wall charges much as possible as.

Y buffer
- To check whether there is failure of the Y Main, firstly check normal operation of the Y buffer.
- After separating both the Y Main and the Y buffer connector,
- Check forward voltage drop of 0.4V ~ 0.5V by diode check between OUTL and OUTH.
- In addition, resistance between both ends is also more than several kΩ.

Y Main
- After connecting both the Y Main and the Y buffer, check that output of one of OUT1~8 of the Y buffer is done as follows in application of power

X Main
- Check output of the TPOUT on the X board is done as follows in application of power

Definition of Name and Terms on Logic Board.

Explanation of Logic Board
Logic board is composed of a logic main board that generates and outputs the address driver output signal and the XY driving signal by processing image signal, and a buffer board that buffers the address driver output signal and delivers it to the address driver IC (COF Module).

Trouble Shooting procedure for any PDP Set

L227A31 - AOC LCD monitor SMPS and audio output circuit diagram - 715T2210-1-A0 SMPS, 715T2448-1 AUDIO

AOC E227ANND2WA1N, AOC E227ANND2WA4N, AOC E227MNND2WA4NN LCD Monitors   Used ICs: TEA1530AT, STP10NK70ZFP(FET), OZT1060GN, AM4502C-T1-PF, TDA7266

SMPS and back-light inverter schematic

Audio output schematic

Picture defects and causes of LCD TVs. Main board fault – T Con board fault.

The reference T’Con here is for LG 32 inch LCD TV.  But, the picture defects can be taken as a reference to LCD TVs of all brands, irrespective of its screen size.

Assy board plate Defects

Horizontal block

Vertical line block

Bright and Dark Spot

Back-light defects

Dark Spot Model The ones of LED

Cause: LED does not light in.

Horizontal Stain Lamp Models (LCD)

Cause: Burning Lamp mead

Impurity

PCB / T-CON Defects

Abnormal image 

NO IMAGE

Backlight lights up more does not generate image

T-Con measurement points

Before changing a module, check that the voltages of the T-Con board are correct.

If one of them is changed, check to be sure that the flat cable that goes to the panel is released.

Check if it is normal if this does not occur and a defect.

Mounting the connector (A) 30 Pins in the Arrow Pin (1)

1-12V enters the Fuse pins 1 to 4 of the Connector (A).

2- The same is done with the GND, Pins 5 to 8 of connector (A) that are connected in short.

3- Only Pin 30, connector (A) enters the voltage of 3.3V

Mounting the connector (B) - 51 pins on the Pin arrow (1)

1- See that 12V power supply is connected directly to the Fuse pins 48 to 51 of connector (B) that are shorted.

2. The same is done with the GND, connected in the pins 45 to 46 of the connector (B) Which are short-circuited.

3- Only Pin 44, of connector (B) enters the voltage of 3.3V

4- You can put a switch to turn the source on and off

Click on the pictures to  magnify