AOC LM520i Schematic

SERVICE MANUAL

LM520i Monitor

(With CPTXG08 PANEL)

THESE DOCUMENTS ARE FOR REPAIR SERVICE INFORMATION ONLY.EVERY

REASONABLE EFFORT HAS BEEN MADE TO ENSURE THE ACCURACY OF THIS MANUAL; WE CANNOT GUARANTEE THE ACCURACY OFTHIS INFORMATION AFTER THE DATE OF

PUBLICATION AND DISCLAIMS RELIABILITY FOR CHANGES, ERRORS OR OMISSIONS.

MANUFACTURE DATA Feb-22-04

PAGE		TABLE OF CONTENTS
1.	SPECIFICATIONS ....................................................................................................		3
	1-1	GENERAL SPECIFICATIONS ...................................................…..............	3
	1-2 LCD MONITOR DESCRIPTION ..................................................................		4
	1-3	INTERFACE CONNECTOR .................................................................…….	4
2.	PRECAUTION AND NOTICES ................................................................................		5
	2-1	ASSEMBLY PRECAUTION .........................................................................	5
	2-2	OPERATIONG PRECAUTION .....................................................................	5
	2-3	STORAGE PRECAUTION …........................................................................	5
	2-4 HIGH VOLTAGE WARNING .......................................................................		5
3.	OPERATING INSTRUCTIONS ................................................................................		6
4.	ADJUSTMENT ..........................................................................................................		7
	4-1 ADJUSTMENT CONDITIONS AND PRECAUTIONS ...............................		7
	4-2 ADJUSTMENTS METHOD .& DESCRIPTION...........................................		7
	4-3 FRONT PANEL CONTROL KNOBS ............................................................		8
5.	CIRCUIT & SOFTWARE DESCRIPTION ................		9
	5-1 THE DIFFERENT BETWEEN EACH PANEL …………………………….		9
	5-2 SPECIAL FUNCTION WITH PRESS KEY ………………………………..		10
	5-3 SIMPLE INTRODUCTION ABOUT LM500 CHIPSET …………………...		11
	5-4	SOFTWARE FLOW-CHART	13
6.	TROUBLE SHOOTING.............................................................................................		15
	A).MAIN BOARD TROUBLE SHOOTING CHART .. ....................................		15
	B). INVERTER - MODULE TROUBLE SHOOTING CHART ...........................		19
7.	MECHANICAL OF CABINET FRONT DIS-ASSEMBLY......................................		21
8.	PARTS LISTING .........................................................................................………...		22

9.SCHEMATIC.............…………………………………............................................ 34

10. PCB LAYOUT .....................................................................………………………...

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	1. SPECIFICATIONS FOR LCD MONITOR
1-1 General specifications
1. LCD-PANEL :
Active display area	15 inches or 15.1 inches diagonal
Pixel pitch	0.297 mm x 0.297 mm
Pixel format	1024 x 768 RGB vertical stripe arrangement

2.Display Color :

6-bit, 262144 colors or 8-bit, 16.7 million colors

3.●External Controls :

a).Power On/Off, Auto key, Rotary-knob ( for shuttle) b).Power On/Off, Auto key, Left key, Right key ( for 4-key ) ●OSD menu Controls

Contrast, Brightness, Focus, Clock,H-position, V-position, Language, Recall-C2(warm color), Recall-C1 (Cool color), Reset, Exit-OSD, Red, Green, Blue

4.Input Video Signal : Analog-signal 0.7Vpp

Video signal termination impedance 75 OHM

5.Scanning Frequencies :

Horizontal:	29	KHz - 63 KHz
Vertical:	55 Hz – 75 Hz
Pixel clock:	80	MHz

6.Factory Preset Timing : 18 User Timings : 19

Input signal tolerance : H tolerance ±1 K, V tolerance ±1 Hz

7.Power Source :

Switching Mode Power Supply

AC 100 – 240 V, 50/60 Hz Universal Type

8.Operating Temperature : 5 - 35 Ambient Non-operating Temperature : -20 - 60

9.Humidity :

Operating : 20% to 80% RH (non-condensing)

Non Operating : 5% to 95%RH (38.7 maximum wet bulb temperature)

10.Weight : 3.0 kg

11.External Connection : 15Pin D-type Connector, AC power-Cord

12.View Angle : x-axis right/left = 60, y-axis up/down = 45 ,45

13.Outside dimension : Width x Height x Thickness = 356mm x 358mm x 160mm

14.Plug and Play : VESA DDC1/DDC2B

15.Power saving : VESA DPMS

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1-2 LCD MONITOR DESCRIPTION

The LCD MONITOR will contain an main board, an inverter/power board, keypad board and internal adapter which house the flat panel control logic, brightness control logic and DDC.

The power board will provide AC to DC Inverter voltage to drive the backlight of panel and the main board chips each voltage.

Monitor Block Diagram

	CCFL Drive.	Flat Panel and
		CCFL backlight

Power board			Main Board
								RS232 Connector
(include: adapter, inverter)
								For white balance
								adjustment in factory
								mode
			Keyboard
AC-IN				HOST Computer				Video signal, DDC
100V-240V

1-3 Interface Connectors

(A)AC-Power Cable

(B)Video Signal Connectors and Cable

(C)Audio Cable

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2. PRECAUTIONS AND NOTICES

2-1 ASSEMBLY PRECAUTION

(1)Please do not press or scratch LCD panel surface with anything hard. And do not soil LCD panel surface by touching with bare hands (Polarizer film, surface of LCD panel is easy to be flawed)

In the LCD panel, the gap between two glass plates is kept perfectly even to maintain display characteristic and

reliability. If this panel is subject to hard pressing, the following occurs :

(a) Uniform color (b) Orientation of liquid crystal becomes disorder

(2)Please wipe out LCD panel surface with absorbent cotton or soft cloth in case of it being soiled.

(3)Please wipe out drops of adhesive like saliva and water in LCD panel surface immediately. They might damage to cause panel surface variation and color change.

(4)Do not apply any strong mechanical shock to the LCD panel.

2-2 OPERATING PRECAUTIONS

(1)Please be sure to unplug the power cord before remove the back-cover. (be sure the power is turn-off)

(2)Please do not change variable resistance settings in MAIN-BOARD, they are adjusted to the most suitable value. If they are changed, it might happen LUMINANCE does not satisfy the white balance spec.

(3)Please consider that LCD backlight takes longer time to become stable of radiation characteristic in low temperature than in room temperature.

(4)Please pay attention to displaying the same pattern for very long-time. Image might stick on LCD.

2-3 STORAGE PRECAUTIONS

(1)When you store LCD for a long time, it is recommended to keep the temperature between 5 -35 without the exposure of sunlight and to keep the humidity less than 80% RH.

(2)Please do not leave the LCD in the environment of high humidity and high temperature such as 60 90%RH.

(3)Please do not leave the LCD in the environment of low temperature; below -15 .

2-4 HIGH VOLTAGE WARNING

The high voltage was only generated by INVERTER module, if carelessly contacted the transformer on this module, can cause a serious shock. (the lamp voltage after stable around 600V, with lamp current around 8mA, and the lamp starting voltage was around 1500V, at Ta=25 )

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3. OPERATING INSTRUCTIONS

This procedure gives you instructions for installing and using the LM520 LCD monitor display.

1.Position the display on the desired operation and plug–in the power cord into External Adapter AC outlet. Threewire power cord must be shielded and is provided as a safety precaution as it connects the chassis and cabinet to the electrical conduct ground. If the AC outlet in your location does not have provisions for the grounded type plug, the installer should attach the proper adapter to ensure a safe ground potential.

2.Connect the 15-pin color display shielded signal cable to your signal system device and lock both screws on the connector to ensure firm grounding. The connector information is as follow:

1	5
6	10
11	15

15 - Pin Color Display Signal Cable

PIN NO.	DESCRIPTION	PIN NO.	DESCRIPTION
1.	RED	9.	5V power from VGA-card
2.	GREEN	10.	GND
3.	BLUE	11.	SYNC. GND
4.	GND	12.	SDA
5.	GND	13.	HORIZ. SYNC
6.	GND-R	14.	VERT. SYNC
7.	GND-G	15.	SCL
8.	GND-B

3.Apply power to the display by turning the power switch to the "ON" position and allow about thirty seconds for Panel warm-up. The Power-On indicator lights when the display is on.

4.With proper signals feed to the display, a pattern or data should appear on the screen, adjust the brightness and contrast to the most pleasing display, or press auto-key to get the best picture-quality.

5.This monitor has power saving function following the VESA DPMS. Be sure to connect the signal cable to the PC.

6.If your LCD monitor requires service, it must be returned with the power cord & Adapter.

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4. ADJUSTMENT

4-1 ADJUSTMENT CONDITIONS AND PRECAUTIONS

Adjustments should be undertaken only on following function : contrast, brightness focus, clock, H-position, V- position, red, green, blue since C1 color & C2 color.

No volume adjust description

4-2 ADJUSTMENT METHOD

Press MENU button to activate OSD Menu or make a confirmation on desired function, Press Left/Right button to select the function or done the adjustment.

1.White-Balance, Luminance adjustment

Approximately 30 minutes should be allowed for warm up before proceeding white balance adjustment.

2.Clock adjustment

Set the Chroma at pattern 63 (cross-talk pattern) or WIN98/95 shut-down mode (dot-pattern). Adjust until the vertical-shadow as wide as possible or no visible.

This function is adjust the PLL divider of ADC to generate an accurate pixel clock Example : Hsyn = 31.5KHz Pixel freq. = 25.175MHz (from VESA spec)

The Divider number is (N) = (Pixel freq. x 1000)/Hsyn

From this formula, we get the Divider number, if we fill this number in ADC register (divider register), the PLL of ADC will generate a clock which have same period with above Pixel freq.(25.175MHz) the accuracy of this clock will effect the size of screen.(this clock was called PIXEL-CLOCK)

3.Focus adjustment

Set the Chroma at pattern 63 (cross talk pattern) or WIN98/95 shut down mode (dot-pattern). Adjust the horizontal interference as less as possible

This function is adjust the phase shift of PIXEL-CLOCK to acquire the right pixel data .

If the relationship of pixel data and pixel clock not so match, we can see the horizontal interference at screen only at crosstalk pattern and dot pattern we can find this phenomena, other pattern the affect is very light

4.H/V-Position adjustment

Set the Chroma at pattern 1 (crosshatch pattern) or WIN98/95 full-white pattern confirm above item 2 & 3 functions (clock & focus) was done well, if that 2 functions failed, the H/V position will be failed too. Adjust the four edge until all four-edges are visible at the edge of screen.

5.MULTI-LANGUAGE function

There have 6 language for selection, press “MENU” to selected and confirm , press “ LEFT” or “ RIGHT” to change the kind of language ( English , Deutch , Francais, Espanol, Italian,Chinese)

6.Reset function

Clear each old status of auto-configuration and re-do auto-configuration ( for all mode)

This function also recall C2 color-temperature , if the monitor status was in “ Factory-mode” this reset function will clear Power-on counter ( backlight counter) too.

7.View Power-on counter and reset the Power-on counter( if not necessary , not suggest to entry factory mode)

The Power-on counter was used to record how long the backlight of panel already working, the backlight life time was guarantee minimal 25000 hours, the maintainer can check the record only in factory mode.

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Press MENU button for 2 seconds along with plug-in AC power cord will be in factory mode, and the OSD screen will located at left top of panel but take cautions don’t press icon “C2” & “C1”, if you press C2/C1 , your white-balance data will overlap with the new-one, and you must perform the white-balance process again.

The result of counter was place at top of OSD, the maximal of record memory was 65000 hours, if exceed 65000 hours the counter will keep in 65000 hours until press “ RESET” at osd-menu in factory mode.

The “ RESET” function in factory mode will execute following function:

1.clear the Power-on counter to zero hours

2.clear old auto-configuration status for all mode , so the monitor will automatically re-do auto-config when change to next mode or power on-off

4-3 FRONT PANEL CONTROL KNOBS

Power button : Press to switch on or switch off the monitor.

Auto button : to perform the automatic adjustment from CLOCK, FOCUS, H/V POSITION, but no affect the colortemperature, and to exit the OSD

Left/Right button : select function or do an adjustment. Or adjust volume MENU button : to activate the OSD window or to confirm the desired function

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5.CIRCUIT-DESCRIPTION

5-1 PANEL SPECIFICATION (CPT XG08)

5-1-1Panel Feature

15” XGA TFT LCD Panel

2 CCFLS Backlight System

Supported (H1024Pixel × V768Lines) resolution

By applying 6 bit digital data

5-1-2 Display Characteristics
	Items	Specification	Unit
	Display Area	304.128(H) x 228.096 (V)	mm
	Driver element	a-Si TFT active matrix
	Display color	Over 16 million	Colors
	Number of pixels	1024 x 768	pixel
	Pixel Arrangement	RGB vertical stripe
	Pixel pitch	0.297(H) x 0.297(V)	mm
	Display Mode	Normally White
5-1-3 Optical Characteristics
The optical characteristics are measured under stable conditions at 25 (Room Temperature)

Item			Symbol	Conditions	Min.	Typ.	Max.	Unit	Note
Contrast Ratio			C/R		300	400	-
(Center of screen)
Response		Rising	Tr			Tf+Tr =35		Msec
Time		Falling	Tf
Luminance of White			YL	Normal	200	250	-	Cd/m2
(Center of screen)
				ψ=0
			Rx	θ=0		0.623
				Viewing
			Ry			0.335
Color				Angle
			Gx		Typ.	0.293	TYP.
Chromaticity
(CIE 1931)			Gy		-0.03	0.599	+0.03
Coordinates (CIE)			Bx			0.144
			By			0.113
			Wx			0.310
			Wy			0.330
Brightness Uniformity			[%]		70	75	-

5-1-4 Parameter guide line for CCFL Inverter

INVERTER MAX BRINGTHNESS (Vadj:5.0v), LOAD=120KΩX4

(ROOM TEMPERATURE 25 ±4 )

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ITEM	SYMBOL	MIN.		TYP.		MAX.	UNIT	REMARK
Input voltage	Vin	10.8	12			13.2	V
Input current	Iin		2250			2500	mA	FOR 4 LOAD
Output Current	Iout	6.0	6.5			7.0	mA	FOR 1 LOAD
Frequency	F	50.0	55.0			60.0	KHZ	FOR 1 LOAD
H.V open	Vopen	1450	1600			1750	Vrms	NO LOAD
H.V Load	Vload	710	810			910	Vrms	RL=120KΩ
Start voltage	Vst	1650	1750			1850	Vrms	RL=CCFL
Protect delay time	PDT	0.4	1			4	Sec
INVERTER MIN BRINGTHNESS (Vadj:0.0v), LOAD=120KΩX4
(ROOM TEMPERATURE 25 ±4 )
ITEM	SYMBOL	MIN.		TYP.		MAX.	UNIT	REMARK
input voltage	Vin	10.8		12		13.2	V
input current	Iin			660		750	mA	FOR 4 LOAD
Output Current	Iout	3.0		3.5		4.0	mA	FOR 1 LOAD
Frequency	F	50.0		55.0		60.0	KHZ	FOR 1 LOAD
H.V open	Vopen	1450		1600		1750	Vrms	NO LOAD
Start voltage	Vst	1650		1750		1850	Vrms	RL=CCFL
H.V Load	Vload	350		450		550	Vrms	RL=120KΩ

5-2 SPECIAL FUNCTION with PRESS-KEY

press Menu button during 2 seconds along with plug-in the AC Power cord:

That operation will set the monitor into “Factorymode”, in Factory mode we can do the White balance adjustment with RS232 , and view the Backlight counter (this counter is use to record the panel activate hours ,for convenient the maintainer to check the panel backlight life time)

In Factory mode, OSD-screen will locate in left top of screen.

Press POWER-button off to on once will quit from factory mode and back to user-mode.

OSD-INDEX EXPLANATION

1.CABLE NOT CONNECTED: Signal-cable not connected.

2.INPUT NOT SUPPORT:

a. INPUT frequency out of range: H > 63kHz, v > 75Hz or H < 28kHz, v < 55Hz

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b.INPUT frequency out of VESA-spec. (out of tolerance too far)

3.UNSUPPORT mode, try different Video-card Setting:

Input frequency out of tolerance, but still can catch-up by our system (if this message show, that means, this is newuser mode, AUTO-CONFIG will disable)

5-3 SIMPLE-INTRODUCTION about LM520A chipset

LCD

Interface

(CN501/CN502))

	Flash				Scalar
	Memory				gm5115/gm2115
A290011TL-70					(Include MCU,ADC,OSD)
	(U202)				(U203)

		EPR_SDA			RXD RGB
		EPR_SCL			TXD
OSD
									DVI-I only
		EEP			D-Sub
Control									Connector
Interface		ROM			Connector				(CN101)
(CN503)		24C16			(CN1)
		DB15_SDA,
		DB15_SCL
					EEPROM				EEPROM(D-I
					24C02				only)
					(U104)				24C02

MODULE-TPYE COMPONENT : Inverter/Power Board

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Inverter Block Diagram

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