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Model
LL-T2000A (serv.man6)
Pages
1 Few pages! See other manuals at the bottom of the first or last page.
Size
12.89 KB
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PDF
Document
Service Manual
Brand
Device
Monitor / (5) Circuit description.
File
ll-t2000a-sm6.pdf
Date

Sharp LL-T2000A (serv.man6) Service Manual ▷ View online

LL-T2000A
5 – 1
CHAPTER5. CIRCUIT DESCRIPTION
1. CIRCUIT DESCRIPTION
(1) General description
The circuit of the LL-2000A is explained using its system block dia-
gram.
The LL-2000A has a 2 RGB input lines which can be selected using
the switch.
The RGB signals (RIN1, GIN2, BIN1, RIN2, GIN2, BIN2) entered
through the CN1 or CN2 from the computer pass through the video
SW (IC27) and are converted into 8-bit digital data (RA, GA, BA, RB,
GB, BB) by the A/D converter before being sent to the scaler (IC1).
The scale (IC1) has a variety of function including CPU, DRAM, syn-
chronizing separation, LCD controller, frame rate conversion, color
adjustment and OSD, in addition to the scaling function. Those func-
tions are controlled by the internal CPU in the scaler (IC1).
The scaler (IC1) detects the frequency and polarity of the synchro-
nizing signal from the synchronizing signals (GHS, GVS) which have
been inputted. From the information obtained, it judges the resolu-
tion of the RGB input and sets the dot clock data to the A/D converter
(IC4) while setting data required for displaying horizontal back-porch
data and vertical back-porch data inside the scaler.
After that, the digital data (RE, GE, BE, RO, GO, BO) processed by
the scaler (IC1) are sent to the LVDS transmitters (IC13, 22) for
matching them to the signal form suitable for driving the panel and
then converted into LVDS signals before being sent to the TFT LCD
panel.
(2) Signal input circuit
RGB analog signals (RIN1, GIN1, BIN1, RIN2, GIN2, BIN2) inputted
through the CN1, CN2 are terminated by resistances (184, 186, 188,
191, 192, 194) and the selection to the input port is made by the
input selection signal SEL from the scaler (IC1) by the video switch.
Both the horizontal synchronizing signals (HS1, HS2) and vertical
synchronizing signals (VS1, VS2) are also selected for the input port
by the input selection signal SEL from the scaler (IC1).
(3) A/D converter circuit
IC4 is an A/D converter which features 3-ch, 8-bit 165 MSPS, and
contains AMP and PLL. RGB analog signals (RIN1, GIN1, BIN1,
RIN2, GIN2, BIN2) from CN1, CN2 are processed by AMP for ensur-
ing proper level, and then A/D converted by the clock generated by
the PLL, and finally outputted as digital video signals to the scaler
(IC1) at the TTL level.
Furthermore, the AMP incorporated in the IC4 is set to the black
level of analog signal by the GBLKSPL signal from the scaler (IC1).
(4) PLL circuit
The PLL circuit creates the memory clock (MCLK) and display clock
(DCLK).
MCLK is created by the IC10 and used as the internal clock of the
scaler (IC1) and the CPU clock.
DCLK is created by the IC11 and used for making the output timing
of the display.
DCLK is stopped and MCLK is decreased in its frequency when
changed into the DPMS mode to meet the requirements for low
power consumption.
(5) FLASH ROM circuit
IC5 has flash memory with a capacity of 4Mbits, which offers the fol-
lowing functions with a 3-V D1 battery: Collective deletion of data on
the chip, deletion per sector, and write of bytes and words.
The flash memory stores firmware to make it possible to upgrade the
firmware at the board assembly level.
(6) D/A converter circuit
The 8-bit D/A converter (IC12) contains an output buffer amplifier
which meets 12C.
The scaler (IC1) CPU D/A converts the values of brightness adjust-
ment signals for the backlight into BRTVR1 and BRTVR2 and sends
them to the inverter.
The voltage adjustment range is determined by the split resistance of
the D/A converter output. The backlight brightness is the maximum
at 0V.
(7) E
2
PROM circuit
IC6 is EEPROM (2 Kword 
u
 8 bit) which meets I
2
C.
It is controlled by the CPU inside the scaler (IC1) and stores default
data and back-up data.
(8) LVDS circuit
This circuit converts digital signals (RE, GE, BE, GO, BO, DE) out-
putted in the 2-pixel mode from the scaler (IC1) into 5 pairs of LVDS
signals with the LVDS transmitters (IC13, 32) to match them to the
panel specification.
(9) Plug and Play
IC17 and IC19 are EEPROMs which meet DDC1/2B. This function
makes it possible to support Plug and Play feature.
(10) Power supply circuit
The main PWB has a DC-DC power supply circuit which creates
power supply necessary for the inside the board, from the 12V DC
sent through the AC adapter.
When the main switch on the main PWB is turned on, the output is
controlled by the MAINPW signal. However, the circuit does not work
normally when the voltage is not proper.
After servicing such components, check the power supply voltage for
correct value.
TP terminals and voltage
GND is PWB outer periphery pattern.
1.
3.3V power supply (DV33), 5V power supply (DVCC, AVCC)
IC14 and IC15 are a voltage drop type switching regulator whose
oscillation frequency is fixed.
IC14 generates DV33 and IC15 generates DVCC and AVCC.
DV33 supplies power to the entire 3.3V system, DVCC to the entire
digital 5V system, and AVCC to the entire analog 5V system.
2.
2.5V power supply (DV25)
IC16 is a series regulator which creates DV25 from 5V power sup-
ply VCC created by IC15, and supplies power to the IC1 scaler.
(11) USB
Password type USB hub.
LD
Symbol
Standard value
Voltage range
Remarks
LD51
V12
12.0V
11.4 ~ 12.6V
LD64
DV33
3.3V
2.7 ~ 3.6V
LD65
DVCC
5.0V
4.75 ~ 5.25V
LD66
DV25
2.5V
2.3 ~ 2.7V
Display

Sharp LL-T2000A (serv.man6) Service Manual ▷ Download

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  • Here you can View online or download the Service Manual for the Sharp LL-T2000A (serv.man6) in PDF for free, which will help you to disassemble, recover, fix and repair Sharp LL-T2000A (serv.man6) Monitor. Information contained in Sharp LL-T2000A (serv.man6) Service Manual (repair manual) includes:
  • Disassembly, troubleshooting, maintenance, adjustment, installation and setup instructions.
  • Schematics, Circuit, Wiring and Block diagrams.
  • Printed wiring boards (PWB) and printed circuit boards (PCB).
  • Exploded View and Parts List.