Sharp LL-T1815 Service Manual ▷ View online
PC-UM10M
LL-T1815-H/B DISASSEMBLY AND ASSEMBLY
3 – 2
C
D
1
2
A
A
6
9
13
14
15
11
12
B
B
D
E
F
G
I
H
H
H
I
I
7
3
4
5
8
10
3. Stand
1)
Remove the five screws
A
and separate the ***
1
from the base
2
.
2)
Remove the cover
3
.
3)
Remove the six screws
B
and remove the ***
4
.
4)
Remove one screw
C
and remove the cover
5
.
5)
Remove the two screws
D
and remove the ***
6
.
6)
Remove the two screws
E
and remove the ***
7
.
7)
Pull the ***
9
out of the ***
8
.
8)
Remove the two screws
F
and remove the ***
F
.
9)
Remove one screw
G
and remove the ***
G
.
10) Remove the three screws
H
and remove the ***
H
.
11) Remove the 17 screws and remove the ***
I
, ***
J
and ***
K
.
PC-UM10M
LL-T1815-H/B TROUBLE SHOOTING
4 – 1
CHAPTER 4. TROUBLE SHOOTING
First of all, check that all the following accessory cables are properly connected.
Also check that the video mode setup of your PC is set to the signal timing conforming to this machine.
Accessory cables
• Exclusive-use AC adapter
• Exclusive-use analog signal cables (RGB cable, DVI-A cable)
• Exclusive-use digital signal cable (DVI-D cable)
THE DISPLAY DOES NOT WORK. (ANALOG RGB)
When the power button is pressed, does the LED
light up?
3
(No)
Execute
1
.
4
(Yes)
When the RGB cable is disconnected, does the
LED turn from Green to Orange?
3
(No)
Execute
1
.
4
(Yes)
When the RGB cable is connected again, does the
LED keep Green?
(Without changing from Green to Orange)
3
(No)
Execute
2
.
4
(Yes)
Does the B/L light up? (
∗
Light leaks from clear-
ance of lead wires on the sheet metal side. )
3
(No)
Execute
3
.
4
(Yes)
Does the display work properly in each video
mode?
3
(No)
Execute
4
.
4
(Yes)
There is no abnormality.
1
4
Is 5V (Main PWB LD69) outputted?
3
(No)
Check IC28 and its peripheral circuits.
4
(Yes)
Is 5V (Main PWB LD69) outputted?
3
(No)
Execute
2
.
4
(Yes)
Do Q8 (1 pin) and R196 supply an output? (4.5V)
3
(No)
Execute
2
.
4
(Yes)
Does FB9
•
CN5 (2 pin) supply on output? (2.0V)
3
(No)
Check Q8 and its peripheral circuits.
4
(Yes)
Do Q7 (1 pin) and R185 supply an output? (4.5V)
3
(No)
Execute
2
.
4
(Yes)
Does FB9
•
CN5 (2 pin) supply on output? (2.0V)
3
(No)
Check Q7 and its peripheral circuits.
4
(Yes)
Check connection of the SW cable and the SW
PWB.
PC-UM10M
LL-T1815-H/B TROUBLE SHOOTING
4 – 2
2
4
Is the input signal port connected to the analog sig-
nal cable?
3
(No)
IPress the INPUT key to switch to the proper input
signal port.
4
(Yes)
Is DC+12V outputted from CN7 3PIN - 9PIN?
3
(No)
Check the power unit.
4
(Yes)
Is LD60 at DC+5V?
3
(No)
Check the DC+5V power line and IC25 peripheral
circuits.
4
(Yes)
Is LD64 at DC+3.3V?
3
(No)
Check the DC+3.3V power line and IC26 peripheral
circuits.
4
(Yes)
Is LD65 at DC+2.5V?
3
(No)
Check the DC+2.5V power line and IC27 peripheral
circuits.
4
(Yes)
Is the voltage across fuse F1 at DC+12.0V?
3
(No)
Check the POWER_CTL signal and IC24 peripheral
circuits.
4
(Yes)
Is the R156 side of C144 at HIGH level (DC+5V)?
3
(No)
Check the RESET circuit in the peripheral of IC17.
4
(Yes)
Is the FB15 level varied by ON/OFF of SW in the
front?
3
(No)
Check the MAINPW_IN signal and wiring of the main
SW from CN5 - SW PWB.
4
(Yes)
Is the Q6 output (connected to R157) changed to
HIGH level after turning on the main SW and then
to LOW level (DC+0V)?
3
(No)
Check Q6 peripheral circuits.
4
(Yes)
Is 21PIN of IC16 oscillating?
3
(No)
Check IC 16 and the clock circuit in the peripheral of
X2.
4
(Yes)
Is the pin on the C113 side of X1 oscillating?
3
(No)
Check IC18 and the clock circuit in the peripheral of
X1.
4
(Yes)
Are the signal waveforms of LD11 and LD12 (LD5,
LD6) normal?
3
(No)
Check the analog signal cable and CN1 (CN2).
4
(Yes)
Is the signal waveform of LD14 (LD15) normal?
3
(No)
Check IC2 peripheral circuits.
4
(Yes)
Are the signal waveforms of LD18 and LD19 nor-
mal?
3
(No)
Check IC3 and IC4 peripheral circuits.
4
(Yes)
Are the signal waveforms of LD22 and LD23 nor-
mal?
3
(No)
Execute
5
. Check the microcomputer circuit. /
GM5060
4
(Yes)
Are the signal waveforms of LD20 and LD21 nor-
mal?
3
(No)
Remove R96/R97 and check if the signal waveform
on the IC8 side is normal or not.
3
(No)
Replace IC8
(Yes)
4
(Yes)
Check the DCLK
•
DEN line.
Is the signal waveform of RN31 - RN35 normal?
3
(No)
Is the positive (+) side (not installed) of C161 at
DC+3.3V?
3
(No)
Check FB17 and IC28 periph-
eral circuits.
(Yes)
4
(Yes)
Is R246 at HIGH level (DC+3.3V)?
3
(No)
Check IC14 peripheral circuits.
4
(Yes)
Remove the LCD module, and check if the signal
waveform of RN31 - RN35 normal or not.
3
(No)
Check IC23 peripheral circuits.
4
(Yes)
PC-UM10M
LL-T1815-H/B TROUBLE SHOOTING
4 – 3
(Yes)
4
Replace the LCD module.
Is the positive (+) side of C162 at DC+12V?
3
(No)
Check IC24 peripheral circuits.
4
(Yes)
Is 7PIN of ICN6 at DC0V?
3
(No)
Check R221.
4
(Yes)
Replace the LCD module
3
4
Is the main PWB LD54 at DC+12V?
3
(No)
Check F3 in the power unit, the power line, and the
FB18 line.
4
(Yes)
Is LD58 at DC+5V?
3
(No)
Check IC14, FB21, D18, and CN8 peripheral cir-
cuits.
4
(Yes)
Is LD56 at DC+2.5V or less?
3
(No)
Check the main PWB and the DC jack PWB in the
peripheral of IC14.
4
(Yes)
Is 1PIN of CN2 - CN7 of the inverter PWB unit at
about 600Vrms? (Use extreme care to prevent
against an electrical shock. Use a high voltage
probe of 100:1 or more for measuring the voltage.)
3
(No)
Replace the inverter PWB unit.
4
(Yes)
Check the lamp in the LCD module.
4
4
Are LD60 and LD61 at DC+5V?
3
(No)
Check the DC+5V power line and IC25 peripheral
circuits.
4
(Yes)
Is LD64 at DC+3.3V?
3
(No)
Check the DC+3.3V power line and IC26 peripheral
circuits.
4
(Yes)
Is LD65 at DC+2.5V?
3
(No)
Check the DC+2.5V power line and IC27 peripheral
circuits.
4
(Yes)
Does the whole display remain black?
3
(Yes)
Is the voltage across fuse F1 at DC+12.0V?
3
(No)
Check F1, IC14 and IC24
peripheral circuits.
(No)
4
(Yes)
Is the oscillating circuit of X1 and X2 normal
(10MHz)?
3
(No)
Check the oscillation circuit of
X1 and X2 in the peripheral of
IC16.
4
(Yes)
Are the signal output of LD20 and LD21 normal?
3
(No)
Execute
2
.
4
(Yes)
Check IC23 peripheral circuits, or CN6 and the LCD
module.
Is the display size abnormal?
3
(Yes)
Are the adjustment items of ADJUSTMENT and
MODE SELECT are properly set?
3
(No)
Set the items properly according
to the LCD display adjustment
procedures.
(No)
4
(Yes)
Check X1, X2, IC15, the peripheral circuits, and the
software.
Click on the first or last page to see other LL-T1815 service manuals if exist.