AOC EN7220 Schematic

EN7220 Service Manual

SERVICE MANUAL

17” LCD Monitor

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 OF THIS INFORMATION AFTER THE DATE OF PUBLICATION AND DISCLAIMS RE LIABILITY FOR CHANGES, ERRORS OR OMISSIONS.

Manufacture Date:Apr-09-04

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EN7220 Service Manual

Table of Contents
Table of Contents ----------------------------------------------------------------------	02
Revision List ----------------------------------------------------------------------------	04
1. Monitor Specification --------------------------------------------------------------	05
2. LCD Monitor Description ---------------------------------------------------------	05
3. Operation Instructions -------------------------------------------------------------	06
3.1 General Instructions -----------------------------------------------------------	06
3.2 Adjusting The Picture ---------------------------------------------------------	06
4. Input/Output Specification -------------------------------------------------------	08
4.1 Input Signal Connector -------------------------------------------------------	08
4.2 Factory Preset Display Modes ---------------------------------------------	09
4.3 Power Supply Requirements -----------------------------------------------	10
4.3.1 Input/Output Requirements --------------------------------------------	10
4.3.2 Inverter Max Brightness ------------------------------------------------	10
4.3.3 Inverter Min Brightness -------------------------------------------------	10
4.4 Panel Specification (QDI L07) ----------------------------------------	11
4.4.1 Display Characteristics -------------------------------------------------	11
4.4.2 Optical Characteristics ------------------------------------------------	12
4.4.3 Parameter guide line for CCFL Inverter -------------------------	12
5. Block Diagram -----------------------------------------------------------------------	13
5.1 Monitor Exploded View -----------------------------------------------------	13
5.2 Software Flow Chart -----------------------------------------------------------	14

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	EN7220 Service Manual
5.3 Electrical Block Diagram -----------------------------------------------------	16
5.3.1 Scalar Board --------------------------------------------------------------	16
5.3.2 Inverter/Power Board ---------------------------------------------------	17
6. Schematic ----------------------------------------------------------------------------	19
6.1 Scalar Board --------------------------------------------------------------------	19
6.2 Inverter/Power Board ------------------------------------------------------	22
6.3 Key Pad Board -----------------------------------------------------------------	24
7. PCB Layout --------------------------------------------------------------------------	25
7.1 Main Board ---------------------------------------------------------------------	25
7.2 Inverter/Power Board --------------------------------------------------------	26
7.3 Keypad Board -----------------------------------------------------------------	26
8. Maintainability -----------------------------------------------------------------------	27
8.1 Equipments and Tools Requirements -----------------------------------	27
8.2 Trouble Shooting -------------------------------------------------------------	28
8.2.1 Main Board -------------------------------------------------------------	28
8.2.2 Power/Inverter Board --------------------------------------------------	31
8.2.3 Key Pad Board ------------------------------------------------------------	33
9. White-Balance, Luminance Adjustment ---------------------------------------	34
10. EDID Content ----------------------------------------------------------------------	35
11. BOM List ---------------------------------------------------------------------	36 50

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		EN7220 Service Manual
1. MONITOR SPECIFICATIONS
	Driving system	TFT Color LCD
LCD Panel	Size	43.2cm(17.0")
	Pixel pitch	0.264mm( H )x 0.264mm( V )
	Viewable angle	140˚ (H) 130˚ (V)
	Response time (typ.)	25 ms
	Video	Analog
Input	Sync. Type	H/V TTL
	H-Frequency	30kHz – 80kHz
	V-Frequency	55-75Hz
Display Colors		Over 16 million Colors
Dot Clock		135MHz
Max. Resolution		1280 x 1024
Plug & Play		VESA DDC2BTM
Power Consumption	ON Mode	<45W
	OFF Mode	<3W
Maximum Screen Size		Horizontal : 13.3”(337.92mm)
		Vertical : 10.6”(270.336mm)
Power Source		100~240VAC,47~63Hz
Environmental		Operating Temp: 0°C to 40°C
Considerations		Storage Temp.: -20°C to 60°C
		Operating Humidity : 15% to 90%
Weight (N. W.)	Packaged	7.4Kgs Unit
	Unpackaged	6.6Kgs Unit

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EN7220 Service Manual

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 Inverter board will drive the backlight of panel and the DC-DC conversion.

Monitor Block Diagram

	CCFT Drive.	Flat Panel and
		CCFL backlight

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

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EN7220 Service Manual

3. OPERATING INSTRUCTIONS

3.1 GENERAL INSTRUCTIONS

Press the power button to turn the monitor on or off. The other control buttons are located at front panel of the monitor. By changing these settings, the picture can be adjusted to your personal preferences.

-The power cord should be connected.

-Connect the video cable from the monitor to the video card.

-Press the power button to turn on the monitor, the power indicator will light up.

3.2Adjusting the Picture

The descriptions for function control LEDS

Main Menu	Main	Sub Menu	Sub Menu		Adjust
	Menu			Description		Reset Value
Item	Icon	Item	Icon		Range
		Contrast		Contrast from Digital-register.	0-100	Recall Cool
						Contrast Value
Luminance
		Brightness		Backlight Adjustment	0-100	Recall Cool
						Brightness Value
		Focus		Adjust Picture Phase to reduce	0-100	Do Auto Config
Image Setup				Horizontal-Line noise
		Clock		Adjust picture Clock to reduce	0-100	Do Auto Config
				Vertical-Line noise.
Image		H. Position		Adjust the horizontal position of	0-100	Do Auto Config
				the picture.
Position		V. Position		Adjust the vertical position of the	0-100	Do Auto Config
				picture.
Color Temp.		Warm	N/A	Recall Warm Color Temperature	N/A	The Color
				from EEPROM.		Temperature will
		Cool	N/A	Recall Cool Color Temperature	N/A	be set to Cool.
				from EEPROM.

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EN7220 Service Manual

		User / Red		Red Gain from Digital-register.	0-100	The User R/G/B
						value(default is
						100) will not be
		User /		Green Gain Digital-register.	0-100
		Green				Modified by Reset
		User / Blue		Blue Gain from Digital-register.	0-100	function.
Auto Config		Yes	N/A	Auto Adjust the H/V Position,	N/A	N/A
				Focus and Clock of picture.
(Analog-Onl
				Do not execute Auto Config,
y Model)		No	N/A		N/A	N/A
				return to main menu.
		H. Position		Adjust the horizontal position of	0-100	50
				the OSD.
OSD Setup		V. Position		Adjust the vertical position of the	0-100	50
				OSD.
		OSD		Adjust the OSD timeout.	10-120	10
		Timeout
		English	N/A	Set OSD display language to	N/A
				English.
		Deutsch	N/A	Set OSD display language to	N/A
				German.
		Français	N/A	Set OSD display language to	N/A	The Language
				French.
Language						will be set to
				Set OSD display language to
		Español	N/A		N/A	English.
				Spain.
		Italiano	N/A	Set OSD display language to	N/A
				Italian.
			N/A	Set OSD display language to	N/A
				Simplified Chinese.
				Show the resolution, H/V
Information		Information	N/A	frequency and input port of	N/A	N/A
				current input timing.
				Clear each old status of
		Yes	N/A	Auto-configuration and set the	N/A	N/A
Reset				color temperature to Cool.
		No	N/A	Do not execute reset, return to	N/A	N/A
				main menu.
Exit		N/A	N/A	Exit OSD	N/A	N/A

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4. Input/Output Specification

4.1 Input Signal Connector

PIN NO.	DESCRIPTION	PI N NO.	DESCRIPTION
1.	Red	9.	+5V
2.	Green	10.	Detect Cable
3.	Blue	11.	NC
4.	Ground	12.	DDC-Serial Data
5.	Ground	13.	H-Sync
6.	R-Ground	14.	V-Sync
7.	G-Ground	15.	DDC-Serial Clock

8.B-Ground

VGA connector layout

1	5
6	10
11	15

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EN7220 Service Manual

4.2 Factory Preset Display Modes

VESA MODES

				Horizontal		Vertical
				Nominal	Sync	Nominal	Sync	Nominal
				Frequenc	Polarity	Freq.	Polarity	Pixel
	Mode	Resolution	Total	y		+/- 1 Hz		Clock
				+/-				(MHz)
				0.5kHz
		640x480@60Hz	800 x 525	31.469	N	59.940	N	25.175
	VGA
		640x480@72Hz	832 x 520	37.861	N	72.809	N	31.500
		640x480@75Hz	840 x 500	37.500	N	75.00	N	31.500
		800x600@56Hz	1024 x 625	35.156	N/P	56.250	N/P	36.000
	SVGA	800x600@60Hz	1056 x 628	37.879	P	60.317	P	40.000
		800x600@72Hz	1040 x 666	48.077	P	72.188	P	50.000
		800x600@75Hz	1056x625	46.875	P	75.000	P	49.500
		1024x768@60Hz	1344x806	48.363	N	60.004	N	65.000
		1024x768@60Hz	1312x813	48.78	N	60.00	N	64.000
	XGA	1024x768@70Hz	1328x806	56.476	N	70.069	N	75.000
		1024x768@72Hz	1304x798	57.515	P	72.074	P	75.000
		1024x768@75Hz	1328x804	60.200	N	74.90	N	80.000
		1024x768@75Hz	1312x800	60.023	P	75.029	P	78.750
	XGA	1152x864@75Hz	1600x900	67.50	P	75.000	P	108.000
	SXGA	1280x1024@60Hz	1688x1066	63.981	P	60.020	P	108.000
		1280x1024@75Hz	1688x1066	79.976	P	75.025	P	135.000
				IBM MODES
				Horizontal		Vertical
				Nominal				Nominal
				Frequenc		Nominal
					Sync		Sync	Pixel
	Mode	Resolution	Total	y		Freq.
					Polarity		Polarity	Clock
				+/-		+/- 1 Hz
								(MHz)
				0.5kHz
	DOS*	720x400@70Hz	900 x 449	31.469	N	70.087	P	28.322
	DOS**	640x400@70Hz	800 x 449	31.469	N	70.087	P	25.175
				MAC MODES
	VGA	640x480@67Hz	864x525	35.000	N	66.667	N	30.240
	SVGA	832x624@75Hz	1152x667	49.725	N	74.551	N	57.2832

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EN7220 Service Manual

4.3 Power Supply Requirements

4.3.1 Input Requirements

INVERTER MAX BRINGTHNESS (Vadj:5.0v), 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		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

4.3.2 Output Requirements

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

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		EN7220 Service Manual
4.4 Panel Specification (QDI L07)
4.4.1 Display Characteristics
PARAMETER	SPECIFICATION	UNIT
Display Size	43(17") Diagonal	cm
Active area	337.9(H) x 270.3(V)	mm
Pixel format	1280(H) x 1024(V)	pixel
	(1 Pixel=R+G+B dots)
Pixel pitch	0.264(H) x 0.264(V)	mm
Pixel configuration	R, G, B vertical stripe
Display mode	Normally White
Unit outline dimensions (typ.)*1	358.5 x 296.5x 16.5	mm
weight	1970(Max.)	g
Surface treatment	Anti-glare and hard-coating 3H
	Low reflection (~ 5%)
Lamp Quantity	4	pcs

4.4.2 Optical Characteristics

The optical characteristics are measured under stable conditions at 25 (Room Temperature)

Parameter		Symbol	Condition	Min	Typ.	Max.	Unit	Remark
	Horizontal	θ21, θ22		65	75		Deg
	Vertical	θ11	CR>10	55	65		Deg
Viewing angle
		θ12		50	60		Deg	Note1,4
range	Horizontal	θ21, θ22			85		Deg
	Vertical	θ11	CR>5		75		Deg
		θ12			70		Deg
Contrast ratio		CR	θ=0°	300	450	—		Note2, 4
Response time		t	θ=0°	—	20		ms
Rise time	tr				4		ms	Note3, 4
Fall time	td				16		ms
Chromaticity of White(CIE 1931)		Wx		0.283	0.313	0.343		Note4
		Wy		0.299	0.329	0.359
Chromaticity of Red(CIE 1931)		Rx		0.603	0.633	0.663
		Ry		0.306	0.336	0.366
Chromaticity of Green(CIE 1931)		Gx		0.270	0.300	0.330

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					EN7220 Service Manual
	Gy		0.556	0.586	0.616
Chromaticity of Blue(CIE 1931)	Bx		0.116	0.146	0.176
	By		0.073	0.103	0.133
Luminance of white	YL		240	300		cd/	IL=7.0
Note 4[Note 4]							mArms
White Uniformity	δw		—	1.25	1.33		Note5
Cross talk					1.50%		Note6

4.4.3 Parameter Guide for CFL Inverter

The backlight system is an edge-lighting type with 2- CCFL(Cold Cathode Fluorescent Lamp).

The characteristics of four lamps are shown in the following tables.

PARAMETER	SYMBOL	MIN	TYP	MAX	UNIT	REMARK
Lamp current range	IL	3.0	7.0	8.0	mArms	Note1
Lamp voltage	VL		725		Vrms
Lamp power consumption	PL		5.1		W	Note2 IL=7.0mA
Lamp frequency	FL		52		kHz	Note3
Established starting voltage	Vs			1100	Vrms	Ta=25	Note4
				1420	Vrms	Ta=0
Lamp life time	LL	40000	50000		hour	Note5

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EN7220 Service Manual

5.2 Software Flow Chart

1

2 Y 3

N

4

5 N

Y

6

7 N 8

Y

9

10	N	11
Y
N 12		13	N
Y		Y
14		15	N 16
		Y
		17

18	N 19
	Y

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EN7220 Service Manual

1)MCU initialize.

2)Is the eeprom blank ?

3)Program the eeprom by default values.

4)Get the PWM value of brightness from eeprom.

5)Is the power key pressed ?

6)Clear all global flags.

7)Are the AUTO and SELECT keys pressed ?

8)Enter factory mode.

9)Save the power key status into eeprom. Turn on the LED and set it to green color. Scaler initialize.

10)In standby mode ?

11)Update the life time of back light.

12)Check the analog port, are there any signals coming ?

13)Does the scalar send out a interrupt request ?

14)Wake up the scalar.

15)Are there any signals coming from analog port ?

16)Display "No connection Check Signal Cable" message. And go into standby mode after the message disappear.

17)Program the scalar to be able to show the coming mode.

18)Process the OSD display.

19)Read the keyboard. Is the power key pressed ?

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EN7220 Service Manual

5.3 Electrical Block Diagram

5.3.1 Main Board

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