LITE-ON H15AAU, H15AAC, H15AAR Service Manual
Service Manual
15-inch LCD Monitor
H15AAU/R
Service Manual Versions and Revision
No. Version Release Date Revision
1. 1.0 Jan. 31, 2002 Original release
Copyright
Copyright 2002 LiteOn Technology Corp.
All Rights Reserved
This manual may not, in whole or in part, be
copied, photocopied, reproduced, translated, or
converted to any electronic or machine readable
form without prior written permission of LiteOn
Technology Corp.
H15AAU / H15AAR Service Manual.
Printed in Taiwan.
Trademarks
LiteOn is a registered trademark of LiteOn
Technology Corp.
All other trademarks are the property of their
respective owners.
Table of Contents
1. Audio circuit --------------------------------------------------------------------------------------------------------------- 1
1.1 Audio input ------------------------------------------------------------------------------------------------------------ 1
1.2 Audio output ---------------------------------------------------------------------------------------------------------- 1
2. Power supply -------------------------------------------------------------------------------------------------------------- 1
3. On-screen circuit ---------------------------------------------------------------------------------------------------------- 2
4. Video input circuit -------------------------------------------------------------------------------------------------------- 2
5. Definition converter LSI peripheral circuit ---------------------------------------------------------------------------- 2
6. System reset, LED control circuit --------------------------------------------------------------------------------------- 2
7. E2PROM for PNP --------------------------------------------------------------------------------------------------------- 2
8. E2PROM -------------------------------------------------------------------------------------------------------------------- 3
9. CPU circuit ----------------------------------------------------------------------------------------------------------------- 3
9.1 Dection of POWER switch status ---------------------------------------------------------------------------------- 3
9.2 Display mode identification ----------------------------------------------------------------------------------------- 3
9.3 User control ----------------------------------------------------------------------------------------------------------- 4
9.4 Control of identification converter LSI ---------------------------------------------------------------------------- 5
9.5 I2C bus control -------------------------------------------------------------------------------------------------------- 5
9.6 Power ON sequence -------------------------------------------------------------------------------------------------- 6
9.7 Power OFF sequence ------------------------------------------------------------------------------------------------- 7
10. Inverter ---------------------------------------------------------------------------------------------------------------------- 8
Circuit Description
H15AAU / H15AAR
1. Audio circuit (Circuit diagrams Main PWB)
1.1 Audio input
The audio signal input received from the audio input terminal (JK011) is applied to the amplifier I001 of 4 (L-
CH) and 9 (R-CH) through the low-pass filter consisting of R040, R041, R042, R043, C040 and C041.
In this amplifier, controls of Volume and mute are conducted. The audio signal controlled at the pin 6 determines
the attenuation of output of the amplifiers. Since then, the signal is output to the jack P003.
1.2 Audio output
The audio signal is output from P002 output terminal of the Audio block to the internal speaker system.
2. Power supply (Circuit daigrams MAIN PWB)
2.1 Line filter consists of C801, T801, C802, C803, C804. It eliminates high frequency interference to meet EMIs
requirement.
2.2 Rec & Filter :
Bridge diode D801 converts AC source into pulsed DC. This pulsed DC is smoothed and filtered by C805.
R802 is an NTC ( negative thermal coefficient ) resistor, used to reduce inrush current to be within safe range.
2.3 Power transformer :
T802 converts energy for square wave from power source C805 to secondary side to generate +12V and +5V.
2.4 Output :
The square wave from T802 is rectified by D809, D810, then filtered by C817, C822 to generate +12V and
+5V respectively.
2.4.1 A 5V power supply for LCD module, CPU and logic is generated from the power source.
2.4.2 I308 : 3-terminal regulator
A 3.3V power supply for I306 analog is generated from the 5V source.
2.4.3 I308 : 3-terminal regulator
A 3.3V power supply for I306 digital is generated from the 5V source.
Q302, Q303 ON/OFF control for LCD Module
ON/OFF control is performed for power ON/OFF and also for the power saving sequence.
2.5 Driver :
Q803 drive T802 from PWM control of I801 for power converted.
2.6 FB :
Negative feedback CKT consists of photo coupler I802 and adjustable regulator I803. It can maintain output
voltages +5V and +12V at a stable level.
2.7 PWM :
2.7.1 Start : When power is turned on, Q801 conducts due to bias from C805 and R805,R803. C807 is charged a 16
volt and a starting current about 0.3mA to pin 7 of I801. I801 starts to oscillate and outputs a pulse train
through pin 6 to drive Q803.
2.7.2 OPP : When Q803 turns on, C805 supplies a linearly increasing triangle current through the primary induc
tance of T802 to the driver Q803, once the peak value of this current multiplied by R811 exceeds1 volt, pulse
train will be shut down immediately to protect Q803, T802 from being burned out.
2.7.3 Regulation : If output voltage +5V goes up, the R terminal of I803 gets more bias, accordingly photo transis
tor and photo diode flows more current. The voltage of pin 2 goes up too, making the pulse width of pin 6 to
become narrower. So the output voltage +5V will be pulled down to a stable value.
Page 1Circuit Description
H15AAU / H15AAR
2.7.4 OVP : If +5V goes up too much, the induced voltage on pin 4 of T802 becomes large also. Suppose that it is
over 18 volts, ZD801 conducts, pin 3 of I801 is pulled up over 1 volt. The pulse train at pin 6 goes down to
zero, shutting Q803 off immediately.
2.7.5 SCP : If output terminal is short to ground, photo transistor does not conduct, hence Q806 does not conduct
either. Then oscillation of I801 is stop, shutting Q803 off immediately.
H15AAU / H15AAR Power Board Block Diagram
Line Filter
Rec.
&
Filter
PWM Driver
Power
Transformer
FB
Output Rec. & Filter
3. On-screen circuit (Circuit diagrams Main PWB)
I300 Embeded function.
On-screen menu screen is established and the resultant data are output from I300 (Circuit diagram MAIN PWB).
4. Video input circuit (Circuit diagram MAIN PWB)
The AC-coupled video signal is used to clamp the black level at 0V).
5. Definition converter LSI peripheral circuit (Circuit diagram MAIN PWB)
I301 MRT V2 gmZAN1 is the definition A/D converter LSI.
The analog R, G, B signal input entered from the video input circuit is converted into the digital data of video
signal through the incorporated A/D converter. Based on this conversion, this device performs interpolation
during pixel extension. The source voltage for this device is 3.3V and the system clock frequency is 12MHz.
The withstand voltage level for the input signal voltage is 3.3V and 5V.
6. System reset, LED control circuit (Circuit diagram MAIN PWB)
6.1 System reset
System reset is performed by detecting the rising and falling of the 5V source voltage at I302.
6.2 LED control circuit
Green / amber is lit with the control signal of the LED GREEN and LED AMBER signal pin 43, 42 from I303
(Circuit diagram MAIN PWB).
7. E2PROM for PnP (Circuit diagram MAIN PWB)
Page 2 Circuit Description
H15AAU / H15AAR
8. E2PROM (Circuit diagram MAIN PWB)
Data transfer between I304 and CPU (Circuit diagram MAIN PWB page 4/7 (I303) is effected through the IIC
bus SCL (pin 9) and SDA (pin 8) of I300 or SCL (pin 42) and SDA pin 39 of I301. The data to be transferred to
each device are stored in I304.
l I300 control data.
l OSD related setting data.
l Other control data for service menu.
9. CPU circuit (Circuit diagram MAIN PWB)
I303 (MTV312M64) (SM89516C25) or (W78E62BP-40) functions as the CPU.
The source voltage for the device is 5.0V and the system clock frequency is 12MHz.
9.1 Detection of POWER switch status
The CPU identifies the ON status of the two power supplies. The identification is made when the power supply
is turned off. For example, if the power supply is turned off with the POWER switch, the POWER switch must be
turned on when activating the power supply again. If the power supply is turned off by pulling out the power
cord, then this power supply can be turned on by connecting the power cord, without pressing the POWER
switch.
9.2 Display mode identification
9.2.1 Functions
(1) Display mode identification
l The display mode of input signal is identified based on Table 1, and according to the frequency and polarity
(HPOL, VPOL) of horizontal or vertical sync signal, presence of the horizontal or vertical sync signal, and the
discrimination signal (HSYNC_DETECT, VSYNC_DETECT).
l When the mode has been identified through the measurement of horizontal and vertical frequencies, the total
number of lines is determined with a formula of Horizontal frequency / Vertical frequency = Total number
of lines. Final identification can be made by examining the coincidence of the obtained figure with the
number of lines for the mode identified from the frequency.
l When the detected frequency if the sync signal has changed, the total number of lines should be counted even
through it is rge identified frequency in the same mode. Then, it is necessary to examine whether the preset
value for the vertical display position of Item 4-3 has exceeded the total number of lines. If exceeded, a
maximum value should be set up, which does not exceed the vertical display position of Item 4-3.
(2) Out-of -range
This out-of-range mode is assumed when the frequency of the horizontal / vertical signal is as specified below.
l Vertical frequency : Below 50Hz or above 85Hz
l Horizontal frequency : Below 24 KHz or above 75 KHz
(3) Power save mode
The power save mode is assumed when the horizontal / vertical signals are as specified below.
l If there is no horizontal sync signal input.
l If there is no vertical sync signal input.
l If the horizontal sync signal is outside the measuring range of I300.
l If the vertical sync signal is outside the measuring range of I300.
Page 3Circuit Description
Table 1
q
(
)
H15AAU / H15AAR
Band Width
KHz
1. 247 VGA 720 x 350 70Hz 31.47 28.322 + -
2. 102 VGA 720 x 400 70Hz 31.47 28.322 - +
3. 103 VGA 640 x 480 60Hz 31.47 25.175 - -
4. 182 MAC 640 x 480 66Hz 35 32.24 - -
5. 173 VESA 640 X 480 72Hz 37.86 31.5 - -
6. 109 VESA 640 X 480 75Hz 37.5 31.5 - -
7. 104 VESA 800 x 600 56Hz 35.16 36 + +
8. 116 VESA 800 x 600 60Hz 37.88 40 + +
9. 110 VESA 800 x 600 75Hz 46.88 49.5 + +
10. 117 VESA 800 x 600 72Hz 48.08 50 + +
11. 108 MAC 832 x 624 75Hz 49.72 57.283 - -
12. 118 VESA 1024 x 768 60Hz 48.36 65 - -
13. 217 SUN 1024 x 768 65Hz 52.45 70.49 - -
(MHz)
PolarityMode No Resolution H-fre
HV
14. 157 VESA 1024 x 768 70Hz 56.48 75 - -
15. 141 VESA 1024 x 768 75Hz 60.02 78.75 + +
Attention :
1. When resolution beyond 1024 x 768 is inputted, resolution is lowered with Down scaling to 1024 x 768, and
indicated, and OSD should indicate OUT of Range.
9.3 User Control
9.3.1 Related ports of I303
Port Pin No. I/O Signal name Function Remarks
P1.5 7 I POWER Power switch input Power ON , OFF
control
P1.1 3 I DOWN switch input ( ) key
P1.0 2 I UP switch input ( ) key
P1.3 5 I - - switch input ( - ) key
P1.2 4 I + + switch input ( + ) key
Page 4 Circuit Description
H15AAU / H15AAR
9.3.2 Functions
Control is effected for the push-switches to be used when the user changes the parameters, in order to modify the
respective setting values. Whether the switch has been pressed is identified with the switch input level that is
turned L.
Each switch input port is pulled up at outside of ASIC.
Each parameter is stored in the EEPROM, the contents of which are updated as required.
9.4 Control of definition converter LSI I300.
9.4.1 Ports related to control
Pin No. I/O Signal name Function
159 I IRQ interrupt signal
5 I/O SCL serial clock
6 I/O SDA serial data
9.4.2 Functions
Major function of I300 are as follows:
(1) Expansion of the display screen.
(2) Timing control for various signal types.
(3) Power-supply sequence (LCD panel).
9.5 I2C bus control
9.5.1 Related ports of I303
Port Pin No. I/O Signal name Function
P1.7 14 O SCL IIC bus clock
P1.6 13 I/O SDA IIC bus data
9.5.2 I2C-controlled functions
The following functional controls are effected by I2C.
(1) Control of EEPROM I304 for parameter setting.
Page 5Circuit Description
H15AAU / H15AAR
9.6 Power ON sequence
When the POWER switch is pressed, the POWER OFF signal is turned H. When this H potential is detected,
the CPU begins to establish the respective power supplies according to the sequence shown below.
POWER
PPWR
D-SHCLK
INV_EN
LED
DATA
Page 6 Circuit Description
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