HP W1907 Service Manual
HP W1907& WF1907 Service Manual
1. Power Board Operation Theory
1.1Line filter consists of C801,T801,C802,C803,C804,C808,C809,C815,C819,C820,C825.It eliminates high frequency interference to meet EMI’s requirement.
1.2Rec&Filter
Bridge diode D812,D813,D814,D815converts AC source into pulsed DC.This pulsed DC is smoothed and filtered by C805.R802is an NTC(negative thermal coefficient)resistor,used to reduce inrush current to be within safe range.
1.3Power transformer:
T802converts energy for square wave from power source C805to secondary side to generate+5V, +12V and +22V.
1.4Output:
The square wave from T802is rectified by D808D809,D810,then filtered by C817,C818,C824,C823, C830,C833, C822to generate+22.5V and+12V,+5V respectively.
1.5Driver:
Q803drive T802from PWM control of I801for power converted.
1.6FB:
Negative feedback CKT consists of photo coupler I802and adjustable regulator I803.It can maintain output voltages+22.5V and+12V,+5V at a stable level.
1.7PWM:
1.7.1Start:When power is turned on.C807is charged a11V and a starting current above40uA
to pin1of I801. I801starts to oscillate and outputs a pulse train through pin6to drive Q803.
1.7.2OPP:When Q803turns on,C805supplies a linearly increasing triangle current through the
primary inductance of T802to the driver Q803,once the peak value of this current multiplied by R811exceeds0.52V,pulse train will be turn off immediately to protect Q803,T802from being burned out.
1.7.3Regulation:If output voltage+22V goes up,the R terminal of I803gets more bias,
accordingly photo transistor and photo diode flows more current.The voltage of pin2goes up too,making the pulse width of pin6to become narrower.So the output voltage+22V will be pulled down to a stable value.
1.7.4OVP:If+2
2.5V goes up too much,the induced voltage on pin4of T802becomes large also.
Suppose that it is over20V.The pulse train at pin6goes down to zero,shutting Q803off immediately.
1.7.5 SCP:If output terminal is short to ground,photo transistor does not conduct,hence I802
does not conduct either.Then oscillation of I801is stop,shutting Q803off immediately.
2. Inverter Circuit
This unit operates on an output voltage of22V from power source.
2.1 VDD:R105get a+5VDC for I101power supply.
2.2 Control IC:I101(OZ9938)
2.2.1 Enable:When pin1of I101is over2V,I101works.If it is under1V,I101turns off.
2.2.2OSC:When I101enabled,C104/R118/R107(pin13of I101)determine the operating
frequency.
2.2.3SST:C106(pin12of I101)provides soft start function.
2.2.4Ignition:IC provides higher operating frequency internally for more striking voltage until
regulation of feedback of lamp current.And provide2sec striking time.
2.2.5Dimming control:The external PWM voltage of R136/C111control the duty pulse of
burst-mode to drive and perform a wide dimming control for the CCFL.The burst-mode frequency is determined by scalor IC.
2.2.6Regulation:Pin5of I101provide regulation of the CCFL current from feedback.The
non-inverting reference is at 1.25V nominal.
2.2.7Protection:Open-lamp protection in the ignition period is provided through pin6of I101.
Removal of the CCFL during normal operation will trigger IC to turns on and shuts off the inverter.This is latch function.
2.2.8 Output drivers:The configuration prevents any shoot-through issue associated with
bridge-type power conversion applications.Adjusting the overlap conduction between Q104,Q105,the CCFL current regulation is achieved.
2.3Half-bridge switching/Transformer:Q104,Q105,C122,C123,C134compose half-bridge switching to convert DC into AC for driver the CCFL.
2.4 Detection:C112,C114,C115,C116,C118,C119,R126,R116,R115,R117,R119,R121,R122,R125 detect the output voltage and ensure a rated voltage by pin6of I101ensure not a open-lamp.
2.5 Feedback:D116,D117,D120,D121,R111,R130sense the lamp current for negative feedback and regulation.
3. Interface Operation
3.1Top (Circuit diagrams sheet 2 of 8)
This page is function block. (1) Power. (2) VGA & DDC interface. (3) DVI & DDC interface. (4) Scaler Gm5726H (Gm5766H). (5) Key & panel interface. (6) Audio.
3.2Power (Circuit diagrams sheet 3 of 8)
3.2.1P301 connector
A 5V power supply for LCD module, also it is main power of interface board. A VDD (+5V)
power supply for audio AMP. It is generated from the P301 connector. And adjust back light of LCD module from I306 sclaer Gm5726H (Gm5766H) control.
3.2.2I302 : 3-terminal regulator
A 3.3V power supply for I306 scaler IC Gm5726H (Gm5766H) and I308 EEPROM / I309
SPI flash ROM, it is generated from the 5V source.
3.2.3I303 : 3-terminal regulator
A 1.8V power supply for I306 scaler IC Gm5726H (Gm5766H), it is generated from the
3.3V source (I302).
3.2.4Q302, I301 : ON/OFF control for LCD module power
ON/OFF control (PANELVCC_EN) is performed for power ON/OFF and also for the power saving sequence. It is support 5V to LCD module power. The PANELVCC_EN signal is generated from I306 scaler IC Gm5726H (Gm5766H).
3.2.5R305 : ON/OFF control for LCD module back light power
ON/OFF control (BKLT_EN) is performed for black light power ON/OFF and also for the power saving sequence. The BKLT_EN signal is generated from I306 scaler IC Gm5726H (Gm5766H).
3.2.6Q301, R301, R302, R304 : Adjust back light luminance of LCD module
It is adjusted back light luminance control (BKLT_ADJ) is performed for the back light luminance. The BKLT_ADJ signal is generated from I306 scaler IC Gm5726H (Gm5766H).
3.3VGA & DDC interface (Circuit diagrams sheet 4 of 8)
This sheet has RGB analog video and H/V sync signals input from VGA connector.
The RGB analog video signals input through AC-coupled, analog video signal is used to clamp the black level at 0V. And H/V sync to sclaer.
Support EDID plug & play function for analog video.
It is to support VESA DDC/CI interface for analog video.
3.3.1P302 connector
The RGB analog video and H/V sync input signals to I306 scaler Gm5726H (Gm5766H).
The VESA DDC/CI function is through I2C bus to I306 scaler Gm5726H (Gm5766H).
3.3.2I304 : EDID EEPROM (24LC02B)
The I304 is support EDID information of the VESA standard for VGA interface, and support plug and play for the PC host.
3.4DVI & DDC interface (Circuit diagrams sheet 5 of 8)
The digital video signals (TMDS) input from P303 DVI-D connector. The digital video signal is TMDS for DVI V1.0 standard. And support EDID plug & play function for digital video.
It is to support VESA DDC/CI interface, and support HDCP function.
3.4.1P303 connector
P303 is DVI-D connector for DDWG standard, it have digital video signals (TMDS) to I306 scaler Gm5726H (Gm5766H). The VESA DDC/CI function is through I2C bus to I306 Gm5726H (Gm5766H). And support HDCP function is also through I2C bus to I306 Gm5726H (Gm5766H).
3.4.2I305 : EDID EEPROM (24LC02B)
The I305 is support EDID information of the VESA standard for DVI interface, and support plug and play for the PC host.
3.5Scaler Gm5726H (Gm5766H) (Circuit diagrams sheet 6 of 8)
The I306 Gm5726H (Gm5766H) is all-in-one LCD monitor controller. The Gm5726H (Gm5766H) leverages Genesis patented advanced image-processing technology as well as a proven integrated ADC/PLL and an Ultra-Reliable DVI compliant receiver to provide excellent image quality. Gm5726H (Gm5766H) also integrates HDCP function, a micro-controller, an OSD controller, and dual LVDS.
The RGB analog video signal from video input circuit enter to incorporated A/D converted block (ADC) into the digital data for analog video signal.
The TMDS digital signals input (with HDCP) entered from the DVI-D connector is converted into the digital data.
Based on this conversion, this device performs interpolation during pixel extension. These interpolation digital data are transformed to LVDS signal. The I306 source voltage is 3.3V and 1.8V, the device clock source frequency is 14.318 MHz. And support DDC/CI interface of VESA and function key operation.
3.5.1I308 EEPROM (24LC16B)
The control data and parameter, and OSD related setting, and other service data, to be stored in I308. The contents of which are updated as required.
3.5.2I309 SPI Flash ROM
The firmware program running from I309 external SPI flash ROM, contains firmware code and data for all firmware function. The device is 2Mbits of flash ROM.
3.5.3I307 Microprocessor Supervisory Circuit
The function of this device is to assert a reset to I306 scaler Gm5726H (Gm5766H), when either the power supply dropped down.
3.5.4X301 1
4.318MHz
It generated reference clock input for I306 scaler.
3.5.5ISP and DDC/CI function
The DDC/CI is VESA standard for the host PC system, it can through I2C bus to control LCD monitor. Enter I306 pin64 DDC_SCL_A and pin65 DDC_SDA_A of the VGA port.
Enter I306 pin66 DDC_SCL_D pin67 DDC_SDA_D of the DVI-D port.
It use ISP function when change new firmware to I309 SPI flash ROM, it used I2C bus from VGA or DVI-D port through I306 Gm5726H (Gm5766H) to I309 SPI flash ROM.
3.5.6The power save sequence function
First I306 pin49 (BKLT_EN) set Low to disable LCD module back light power, delay of some time, then I306 pin127 (PANELVCC_EN) set Low to disable LCD module power, then I306 enter to power down mode.
3.6Key & Panel interface (Circuit diagrams sheet 7of 8)
3.6.1P306 connector
It is LVDS bus, it is from I306 scaler to LCD panel module. The P306 output voltage is 5V.
3.6.2P307 and P308 connector
The P307/P308 has support keypad function. Control is give effect to for the push switch 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 change of I306 Gm5726H (Gm5766H). Related ports of I306 based on Table 1.
Each parameter is stored in the I308 EEPROM, the contents of which are updated as required. The P307 have LED Blue and Amber light, the LED Blue signal from I306 pin126, and the LED Amber signal from I306 pin125.
Table 1 Related ports of I306
Pin No. I/O Signal name Function Remarks
Pin 113 I KEY_POWER Soft power switch input Power key
Pin 115 I KEY_MENU Enter OSD switch input Enter OSD menu
Pin 114 I KEY_UP Switch input Up key or Viewing model selection Pin 115 I KEY_DOWN Switch input Down key or Volume control of
audio function
Pin 114 I KEY_SELECT Selection switch input Select key or Auto adjust key
3.7Audio (Circuit diagrams sheet 8of 8)
3.7.1P309 connector
The P309 is audio signal input from the audio source.
3.7.2P310 connector
The P310 is audio output to speaker and support 2W x 2 speakers.
3.7.3I310 TPA6021A4
The I310 is 2x2W stereo audio amplifier, it is an integrated class-AB dual output amplifier.
3.7.4Q309 : Power down and mute control for Audio
ON/OFF control (AUDIO_EN) is performed for standby mode and mute function. It is support 5V to audio IC power. The AUDIO_EN signal is generated from I306 scaler Gm5726H (Gm5766H).
3.7.5R394, Q310: Volume control for Audio
Volume control (volume) is performed for audio output signal power. The volume signal is generated from I306 scaler Gm5726H (Gm5766H).
3.8Others
3.8.1Detection of POWER ON status
The I306 Gm5726H (Gm5766H) identified the ON status of two modes for the power supplies. The identification is made when the power supply is turn off. For example, if the power supply is turn off with the POWER key switch, the POWER key switch must be turn on when active the power supply again. If the power supply turned off by the pulling out the power cord, then this power supply can to be turned on by connecting the power cord, without pressing the POWER key switch.
3.8.2Display mode identification
3.8.2.1Display mode identification
z The display mode of input signal is identified based on Table 2.
z 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 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. The
Distinction Hsync and Vsync of each mode is shown in Table 3.
z When the detected frequency if the sync signal has changed, the total number
of lines should be counted even through it is range identified frequency in the
same mode.
3.8.2.2Out of range
This out of range mode is assumed when the frequency out of the horizontal /
vertical signal is as specified below.
z Vertical frequency : 50 ~ 76 Hz.
z Horizontal frequency : 24 ~ 83KHz.
3.8.2.3Power save mode
The power save mode is assumed when the horizontal / vertical signals are as
specified below.
z If there is no horizontal sync signal input.
z If there is no vertical sync signal input.
z If the horizontal sync signal is outside the measuring range of I306 Gm5726H
(Gm5766H).
z If the vertical sync signal is outside the measuring range of I306 Gm5726H
(Gm5766H).
Table 2 video mode
Polarity Mode Resolution H-Freq (KHz) Band Width (MHz)
H V
(59.94Hz) 31.469 25.175 - -
1 640x480
(72Hz) 37.861 31.5 - -
2 640x480
(75Hz) 37.5 31.5 - -
3 640x480
(70Hz) 31.469 28.322 - +
4 720x400
(60Hz) 37.879 40 + +
5 800x600
(72Hz) 48.077 50 + +
6 800x600
7 800x600
(75Hz) 46.875 49.5 + +
(74.55Hz) 49.722 57.284 +/- +/-
8 832x624
(60Hz) 48.363 65 - -
9 1024x768
(70Hz) 56.476 75 - -
10 1024x768
(75Hz) 60.023 78.75 + +
11 1024x768
(75Hz) 68.68 100 - -
12 1152x870
13 1152x900
(76Hz) 71.71 105.561 - -
(60Hz) 63.981 108 + +
14 1280x1024
(75Hz) 79.976 135 + +
15 1280x1024
Table 3 the Hsync, Vsync distinction
Indication resolution Distinction Hsync Distinction Vsync The fixed mode 720 x 400 30.5KHz≦fH≦32.5KHz 69Hz≦fV≦71Hz 4 640 x 480 30.5KHz≦fH≦32.5KHz 59Hz≦fV≦61Hz 1 640 x 480 36.9KHz≦fH≦38.9KHz 71.8Hz≦fV≦73.8Hz 2 640 x 480 36.5KHz≦fH≦38.5KHz 74Hz≦fV≦76Hz 3 800 x 600 36.9KHz≦fH≦38.9KHz 59.3Hz≦fV≦61.3Hz 5 800 x 600 47.1KHz≦fH≦49.1KHz 71.2Hz≦fV≦73.2Hz 6 800 x 600 45.9KHz≦fH≦47.9KHz 74Hz≦fV≦76Hz 7 832 x 624 48.7KHz≦fH≦50.7KHz 73.5Hz≦fV≦75.5Hz 8 1024 x 768 47.4KHz≦fH≦49.4KHz 59Hz≦fV≦61Hz 9 1024 x 768 55.5KHz≦fH≦57.5KHz 69.1Hz≦fV≦70.1Hz 10
≦ 11 1024 x 768 59KHz≦fH≦61KHz 74Hz≦fV76Hz
≦≦ 74Hz fV76Hz
≦≦ 12 1152 x 870 67.7KHz fH69.7KHz
≦≦ 13
≦≦ 75Hz fV77Hz
1152 x 900 70.7KHz fH72.7KHz
≦≦ 14 1280 x 1024 62.9KHz fH64.9KHz
≦≦ 59Hz fV61Hz
≦≦ 74Hz fV76Hz
≦≦ 15 1280 x 1024 79KHz fH81KHz
3.8.3Power ON sequence
When the POWER key switch is pressed, the POWER key switch signal is turned “H”.
When this “H” potential is detected, the CPU begins to establish the respective power
supplies according to the sequence show below.
3.8.4Power OFF sequence
When the POWER key switch is pressed, while the power supply is ON, the POWER key switch signal is turned “H”. When this “H” potential is detected, the CPU begins to turn off the respective power supplies according to sequence show below.
3.8.5List of I/O Pin Assignments of the I306
Pin No. Port Signal Name Initial
Setting Function
113 LBADC_IN3
PWR_KEYn H ON/OFF
LCD
monitor
126 GPIO14 LED_B L LED Blue enable when is H
125 GPIO13 LED_A L LED amber enable when is H
114 LBADC_IN2 KEY_UPn H OSD up/plus enable when is 2.46V 115 LBADC_IN1 KEY_MENUn H OSD enter enable when is 2.46V
114 LBADC_IN2 KEY_SELECTn H OSD select/exit enable when is 2.0V 115 LBADC_IN1 KEY_DOWNn H OSD down/minus enable when is 2.0V 86 GPIO31 HDCP_HPDn L DVI HPD enable when is L
122 GPIO10 SCL H EEPROM clock signal of IIC bus
123 GPIO11 SDA H EEPROM data signal of IIC bus
50 GPO4 BKLT_ADJ - Backlight brightness control
124 GPIO12 DDC_WPn L DDC EEPROM write protection when is L
51 GPO0 AUDIO_EN L Audio enable when is H
56 GPO1 VOLUME L Audio
volume
121 GPIO9 VGA_DETn H VGA cable connected when is L 120 GPIO8 DVI_DETn H DVI cable connected when is L
58 GPO3 UART_DO H UART interface data OUT
57 GPO2 UART_DI H UART interface data IN
127 PPWR PANELVCC_EN L Panel power enable when is H
49 PBIAS BKLT_EN L Back light power enable when is H
64 GPIO16 DDC_SCL_VGA H DDC/CI interface for VGA
65 GPIO17 DDC_SDA_VGA H DDC/CI interface for VGA
66 GPIO18 DDC_SCL_DVI H DDC/CI interface for DVI
67 GPIO19 DDC_SDA_DVI H DDC/CI interface for DVI
4.Troubleshooting
4.1No.display of screen(Screen is black,color of LED is amber)
4.2Nothing display on screen screen is black,color of LED is blue
(
4.3Checking the back light unit
4.4Abnormal screen
4.4.1Abnormal screen for VGA source
4.4.2Abnormal screen for DVI source
4.5Abnormal OSD display adjust problem
4.6Abnormal plug and play operation
4.6.1Abnormal plug and play operation for VGA
4.6.2Abnormal plug and play operation for DVI