Acer V173 LCD Monitor How to enter service mode, firmware update, SMPS circuit diagram

When replacing parts or circuit boards, clamp the lead wires around terminals before soldering.
Keep wires away from high voltage, high temperature components and sharp edges.
Keep wires in their original position so as to reduce interference.
Adjustment of this product please refers to the user’ manual.

ACER BV173 is designed with LVDS interface and dual (VGA&DVI) input, it featured with embedded universal AC power supplies. It’s a green product and meets all ROHS standard. The power button and display control buttons are on the front of the monitor. The monitors shall automatically display lower resolution video modes into 1280x1024 full screen display .The image can be adjusted through OSD control.

OSD Function Test

Test mode: 1280x1024 @ 60 Hz

Test pattern: pattern #1 of crosshatch (GENERAL-1)

Check single key function and hot key function about key “Power”, “Menu”,” ►”, “◄ “, Exit/Auto”, “[e Color ]” it should operate normally.

Screen Picture Check
Test mode: 1280x1024 @ 60 Hz
Test pattern: pattern #1 of crosshatch (GENERAL-1)
Select OSD menu to execute ‘Auto’ function, screen picture shouldn’t appear abnormal phenomenon and picture on screen should fit in with active display screen.

Auto Color Balance
Test mode: 640X480 @ 60 Hz
Test pattern: pattern #42 of 5 mosaic pattern
Enter "Factory Mode" pressing "MENU" key, execute "AUTO".
When Color Balance finished, Must push “POWER” key to exit “Factory mode”, and restart.

Timing Check

Test mode: Refer to preset timing table and power saving mode

Test pattern: pattern #1 of crosshatch (GENERAL-1)

After change above timing and execute “Auto” function automatically, picture should fit in with active display screen.

Under power saving mode, LED lamp on the key board should be orange

Power Consumption Function Test

Test mode: 1280x1024 @ 60 Hz

Test pattern: pattern #41 of “WHITE”

Adjusting both brightness value to maximum

VGA Cable Detect Test

If VGA cable of LCD monitor isn’t connected to video pattern generator or PC, “NO SIGNAL” should be shown on screen.

Hi-Pot test
Test condition:
a. high voltage 2.3KV(DC)
b. leakage current 10mA
c. rising time 1 sec.
d. test time 3 sec.

Grounding Test
Test condition:
a. test current 30A / 2 sec
b. impedance < 0.1Ω

DISPLAY CHECK
Panel Flicker Check
Connect LCD monitor to PC, set LCD monitor to be timing of 1280x1024@60 Hz, adjust brightness to be default value (brightness at maximum), execute “Auto” function, and then check picture of shut down under windows operating system, or flicker-pattern of pixel on-off. It should be that no flicker be found on panel screen

Panel Defect Inspection
Test mode: 1280 x 1024@60Hz
Test pattern: Crosshatch/Full white/Red/Green/Blue/Black/16 color bar/64 gray bars
Display quality must be (according to DIN 13406-2 pixel fault class II)

Note 1: Dot defect is defined as the defective area is not larger than 50% of the dot area. Bright Dot is defined 5% transmission ND filter.
Note 2: Light Leakage: There shall not be visible light around the customer’s bezel after assembly in normal View angle.

SOP of firmware upgrade (Manufacturer of Scaler is RealTek)

Equipment: PC, ISP card, signal cable and power cable.

ESD requirements: anti-static wrists, anti-static gloves (fingers), and connecting cable

Name of ISP program: RTDTool_4.6.exe

Manufacture of FW IC：RTD 2525L

Operational steps:
1. Connection: connect PC to PCBA with signal cable, and then keep AC and DC in open state

2. Adjust ISP programming
Double click RTDTool_4.6.exe and open ISP program, then select “25XXV/2525L”, and RTD 2120 ISP button.

Select Bank2 size which is 30.

Click “64K”button and download FW file.

Click “64~96”button, and download extern FW file

“program “button, then you will see ISP will going on. There will be prompting if programming is OK.

Factory Mode [Service mode]

Click on the picture to magnify

Switching Mode Power Supply
AC Current Input Circuit
P801 is a connector for connecting AC Power. F801 is a fuse to protect all the circuit. AC input voltage is from 90v to 264V. R801 and R802 joined between two inputting main circuit to prevent from shock. L801 is used to clear up low frequency wave. C801 and C802 are used to discharge the waves that L801 produced. High frequency waves are damped by C801 and C802. D801 is a rectifier which composed of 4 build-in diodes, it inverts AC to DC.
High Voltage to Low Voltage Control Circuit C804 is used to smooth the wave from rectifier. IC802 is a highly integrated PWM controller.  When rectified DC high voltage is applied to the Vcc pin during start-up, the MOSFET Q804 is initially off, and the Vcc pin capacitor is charged. When the Vcc pin voltage reaches approximately 10V, the control circuitry is activated and the soft-start begins. The soft-start circuit gradually increases the duty cycle of the MOSFET from zero to the maximum value over approximately 4ms. If no external feedback/supply current is fed into the CS pin by the end of the soft-start, the current Set point will be above the fault level, FAULT flag is raised, if the FAULT duration exceeds 80ms, the output controller disable.

Resistor R808, R809, R810, R811 are for line over voltage shutdown(OVP) When PWM is turned off, the main current flow will be consumed through R804 and D802, This will prevent MOSFET Q804 from being damaged under large current impulse and voltage spike. D804 and C807 to provide internal Auxiliary voltage to Vcc pin during normal operation. Otherwise, error amplifier and feedback current input the CS pin for duty cycle control.

 DC_5V and DC_14V Output Circuit

For DC 5V, D805 is used to rectify the inducted current. R828 and C814 are used to store energy when current is reversed. The parts including C818, C822, C820,L803 are used to smooth the current waves.

For DC 14V, D803 is used to rectify the inducted current. R827 and C813 are used to store energy when current is reversed. The parts including C815, C817 and L802 are used to smooth the current waves.

Feedback and OVP Protect Circuit

Pin R of IC803 is supplied 2.5-v stable voltage. It connects to 5V and 14V output through R822, R823 and R824. R822, R823 and R824 are output sampling resistor. When the sampling voltage more than 2.5V or less than 2.5V, current of FB IC802 will change, this can change the voltage from T801.  OVP Protect Circuit: When output is overvoltage, the auxiliary winding voltage will be increased, when it reaches about 14V. Q803 is triggered. It makes the IC802 Pin 1 exceed 5V, and then the IC802 output will be disabled.

Q801, R816, R817 and ZD803 make up of dummy loading circuit. For start-up sequence, during 5V output take place high loading first, this dummy loading circuit operated to insure 14V not be increased.

InnoLux BV173 SMPS board schematic

Inverter circuit

14VDC provides the power for IC501; the control signals Brightness and ON/OFF come from I/F board. ON/OFF signal connect to pin8 of IC501 and makes IC501 enable. Brightness signal connect to pin7 of IC501 and regulates the panel brightness, R510 , R511, C507 make up a network of delaying time circuit . The striking frequency is determined by the external Resistor R505 pin5 of IC505and r516. The operation frequency is determined by the external Resistor R505 pin5 of IC505. the capacitor and resister connected to pin4 to set striking time and shunt down delay time. BURST MODE dimming pulse frequency and duty is regulated by I/F board.

The output drives, include square pulses output of pin14,12,11 to drive MOSFET U501, U502, and U501, U502 are N channel MOSFETs. U501 and U502 work as half-bridge topology. Two transformers are connected in parallel with each transformer driving two lamps in series. Turning each N-Channel MOSFET “on/off” complementarily, produces an alternating current through the transformer primary and secondary. The “on” duration of the switches determines the amount of energy delivered to the CCFLs.  The current flowing through CCFL is sensed and regulated through sense resistor R502, R543. The feedback voltage connected to Pin2 (ISEN), then compared with a internal reference voltage, resulting in PWM signal outputs to adjust output voltage.

Over Voltage Protection and over-current protection are monitored by the voltage on OV(Pin 1) and LI (Pin2) During normal operation , if a CCFL is damaged or removed ,the voltage at OV (Pin6) increases .Once the voltage at OV Pin exceeds 1.2V (OVPT Setting) the driver output duty cycle is regulated and the shutdown delay timer is activated. Once over the delay time the IC will shut down