LL-T1500A (serv.man15). Chapter 4 Troubleshooting - Sharp Monitor Service Manual (repair manual)

ll-t1500a (serv.man15) service manual
Model
LL-T1500A (serv.man15)
Pages
3 Few pages! See other manuals at the bottom of the first or last page.
Size
26.84 KB
Type
PDF
Document
Service Manual
Brand
Device
Monitor / Chapter 4 Troubleshooting
File
ll-t1500a-sm15.pdf
Date

Read Sharp LL-T1500A (serv.man15) Service Manual online

CHAPTER 4. TROUBLESHOOTING (for checking PWBs)
Make sure that the following accessory cables are connected properly.
In addition, make sure that the video mode of the personal computer is properly set to the signal timing supported by this machine.
ACCESSORY CABLES
·
Power cable
·
USB cable
Check for defective parts in the
following manner.
Does the light of the LED change from orange
to green when pressing the power-on switch?
No
(1) See <An error occurs when detecting the
      synchronizing signal.>
Remove the RGB cable. Does LED
come on in orange after for a while?
(2) See <An error occurs when using the
      Power Save mode>
Connect the RGB cable. 
Does the backlight come on?
(3) See <Backlight goes out improperly>.
Does the screen display normally
in each video mode?
(4) See <Screen error>
Do the USB units operate normally?
(5) See <USB error>.
Yes
No error
(1) <An error occurs when detecting the synchronizing signal>
Is DC+12V outputted from the
power supply unit?
Check the power supply unit and
fuses (power supply unit).
Is B13 at DC+12V?
Check the DC+12V power line (12V), and the
power supply circuit for the fuse F1.
Is the signal input of the 5th pin of
the U17 at low level (0V)?
Check the power supply circuit for the operation PWB
(operation PWB and cables) and that for the U17.
Is the 4th pin of the U17 at DC+15V?
Check the DC+15V power supply line (5Va)
and the power supply circuit for the U17.
Is the signal input of the 11th pin of
the U10 at low level (0V)?
Check the REST circuit for the U10.
Is the signal input of the 22nd pin of the
U10 normal? (See Waveform diagram 1.)
Check the clock circuit for the U10 and X1.
Is the signal input of the 4th pin of
the U16 at low level (0 V)?
Check the power supply circuit for the operation PWB
(operation PWB and cables) and that for the U16.
Is the 8th pin of the U16 at DC+12V?
Check the DC+12V power line (12 Va) and
the power supply circuit for the U16.
Is the signal input of the 17th pin of the U10
normal? (See Waveform diagrams 2, 3.)
Check the signal cable and the synchronizing
signal processing circuit for the U10 and U21.
Is the signal output of the 27th pin of
the U10 at low level (0 V)?
Check the microprocessor control circuit
for the U10.
Is the signal output of the 42nd pin of
the U10 at high level (DC+5V)?
Check the microprocessor control circuit
for the U10.
Check the operation PWB and related
parts (LED and cables).
Yes
Yes
Yes
Yes
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
(2) <An error occurs when using Power Save mode>
Is the signal input of the 42nd pin of
the U10 at low level (0 V)?
No
Check the microprocessor control circuit
for the U10.
Check the operation PWB and related
parts (LED and cables).
(3)  <Backlight goes out improperly>
Is the 5th pin of the JP2 at DC+12V?
Check the CD+12V power line (12 V) and
the power supply circuit for the JP2.
Is the signal input of the 26th pin of
the U10 at low level (0 V)?
Check the microprocessor control circuit
for the U10.
Is the 1st pin of the JP2 at DC+5V?
Check the DC+5V power line (5 Va) and the
power supply circuit for the U17.
Yes
Yes
No
No
Yes
Yes
No
Check the inverter PWB unit.
Check the lamp inside the LCD module.
(5) <USB error>
Is DC+12 V outputted from the
power supply unit?
Check the power supply unit and
fuses (power supply unit).
Replace the USB unit with a new one.
Yes
Yes
No
No
Yes
Are the 1st pins of the inverter PWB
units CN2 and 3 at about 1500 Vrms?
(Use due caution not to get an electric
shock accident. For measuring the
voltage, use a high-voltage probe of
more than 100:1. )
Is the 26th pin of the U17 at 0 V when
the backlight luminance is at the
maximum (OSD BRIGHT31)?
Check the operation PWB (operation PWB
and cables) and the microprocessor control
circuit for the U10 and U17.
No
No
Yes
Is the 3rd pin of the JP2 at 0 V when the
backlight luminance is at the maximum
(OSD BRIGHT31)?
Check the backlight control circuit for the JP2.
(4) <Screen error>
Is the signal output of the 25th pin of
the U10 at low level (0 V)?
No
Check the microprocessor control circuit for
the U10.
Yes
It the 8th pin of the U18 at DC+5V?
Check the DC+5 V power supply line (% Vb)
and power supply circuit for the U18.
Is the signal output of the 1st pin of
the U12 at high level (Cd+5 V)?
Check the power supply control circuit for
the U12.
Is the 2nd pin of the U14 at CD+3.3 V?
Check the DC+3.3 V power supply line (3.3 Vb)
and the power supply circuit for the U14.
Does the entire screen of the LCD
remain white?
Check the LCD connector and LCD module.
Check the LCD control signal
circuit for the U1 and U3.
Does the entire screen of the LCD
remain black?
Check the LCD control signal circuit for
the U1 and U3.
Is the size of the LCD screen abnormal?
Are the adjustment items, ADJUSTMENT,
MODE, and SELECT, properly set?
Check the LCD control signal circuit for
the U1 and U3.
Adjust and set the adjustment
items properly, following the
screen adjustment procedure.
Check the PLL circuits for the
U2, U4, U5, U6, U10, and U11.
Does the LCD screen jolt or flicker?
Are the adjustment items ADJUSTMENT,
MODE, and SELECT set properly?
Check the PLL circuits for the U2,
U4, U5, U6, U10, and U11.
Adjust and set the adjustment
items properly, following the
screen adjustment procedure.
Do the colors of the LCD screen
abnormal?
Are the adjustment items GAIN, CONTROL,
and WHITE BALANCE properly set?
Is the digital color signal output of the U2
normal? (See Waveform diagram 9.)
Is the digital color signal input and output of
the U1 normal? (See Waveform 10.)
Check the LCD connector and LCD module.
Adjust or set the adjustment
items, following the screen
adjustment procedure.
Check the video amplifier
circuit for the U7.
Check the AD conversion
circuit for the U2.
Check the color signal
processing circuit for the U1
and U3.
Is the OSD display of the LCD screen
abnormal?
Check the color signal processing circuit for
the U1 and U3.
Check the OSD display circuit
for the U8, U10, and U11.
Is the LCD screen normal at the time of
composite sync or sync-on green?
Check the synchronizing signal processing
circuit for the U7, U19, U21, U22 and U23.
Check the memory circuit for the U10 and u11.
The LCD unit is normal.
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
No
No
No
Yes
Yes
Yes
No
No
No
No
No
Yes
Yes
No
No
No
Yes
Yes
No
Are the signal outputs of the 9th and 14th pins
of the JP4(See Waveform diagrams 4 and 5.)
Are the output signals of the 15th pin of the U5
and the 8th pin of the U2 normal?
(See Waveform diagrams 6 and 7.)
Are the analog color signal outputs of the 29th
pin, 32nd pin, and 35th pin of the U properly
set? (See Waveform diagram 8.)
Are the signal outputs of the 13th pin, 14th pin
and 15th pin of the U8 normal?
(See Waveform diagram 11.)
Page of 3
Display

Download Sharp LL-T1500A (serv.man15) Service Manual (Repair Manual)

Here you can read online and download Sharp LL-T1500A (serv.man15) Service Manual in PDF. LL-T1500A (serv.man15) service manual will guide through the process and help you recover, restore, fix, disassemble and repair Sharp LL-T1500A (serv.man15) Monitor. Information contained in service manuals typically includes schematics / circuit diagrams, wiring diagrams, block diagrams, printed wiring boards, exploded views, parts list, disassembly / assembly, pcb.