Read Sharp LL-T1620 (serv.man14) Service Manual online
PC-UM10M
LL-T1520-H/B LL-T1620-H/B TROUBLE SHOOTING
4 – 1
CHAPTER 4. TROUBLE SHOOTING
First of all, check to confirm that all the accessory cables below are
properly connected.
properly connected.
Also check to confirm that the PC's video mode is set to match the sig-
nal timing supported by this machine.
*
Accessory cables
• Exclusive-use AC cable
• Exclusive-use analog signal cable (RGB cable)
• Exclusive-use digital signal cable (DVI-D cable)
The display does not work (with analog signal input, RGB cable)
(Yes)
(Yes)
(Yes)
(Yes)
(Yes)
(Yes)
When the power button is pressed, does the
LED turn green ?
LED turn green ?
Is the input signal port connected to the analog
signal cable ?
signal cable ?
Is the level of IC13-85P changed by turning
ON/OFF the power button ?
ON/OFF the power button ?
Press the INPUT key to select the suitable
input signal port.
input signal port.
(Yes)
(Yes)
(No)
(No)
(Yes)
(No)
(No)
(No)
(Yes)
(Yes)
(No)
(No)
(No)
(No)
(No)
(Yes)
(No)
(Yes)
(No)
(Yes)
(No)
(No)
Perform 1
Is the display normal in each video mode ?
Does B/L light up ?
No abnormality
Check the AC cable connection.
Check the power unit switch.
Check IP3 and IC24 peripheral circuit.
Check IP2 and IC25 peripheral circuits.
Check IC10 and IC20 peripheral circuits.
Check X1 and peripheral circuits.
Check IC23 and peripheral circuits.
Check IC30 peripheral circuits.
Check XPON signal and CN7 peripheral
circuits.
circuits.
Check EDSDA signal, EDSCL signal, IC13
and IC21 peripheral circuits.
and IC21 peripheral circuits.
Check the analog signal cable and CN2
peripheral circuits and IC5 peripheral circuits.
peripheral circuits and IC5 peripheral circuits.
Check the power unit and the power cable.
Is the power unit switch ON ?
Is the AC cable connected to the power unit ?
Is DC+12V supplied to CN16-1P ?
Is IP2 at DC+5V ? (LL-T1520H/B only)
Is FB30 at DC+3.3V ?
Is RESET signal delivered from IC23 ?
Is X1 oscillating ?
Are FB20 and FB29 at DC+2.5V ?
Is IP3 at DC+5V ? (LL-T1620H/B only)
(Yes)
(Yes)
(Yes)
(No)
(No)
(No)
(Yes)
(No)
Check Q6 Q7, and peripheral circuits.
Check IC13 and IC17 peripheral circuits.
Are the addresses and data signal of IC13 and
IC17 correct ?
IC17 correct ?
Check the SW PWB , the SW cable, and their
connection.
connection.
Are signals of R112 and R113 normal ?
Is the signal at IC13 39 40pin normal ?
Are signals of R19 and R71 normal ?
1
Perform 2
Perform 3
PC-UM10M
LL-T1520-H/B LL-T1620-H/B TROUBLE SHOOTING
4 – 2
(No)
(Yes)
(Yes)
(No)
(Yes)
Check the power unit, the power cable, their
connection, the DC+12V power line, and IP1.
connection, the DC+12V power line, and IP1.
Is CN10-6P at DC+1.0V or below when the
brightness is maximum ?
brightness is maximum ?
Is the inverter PWB normal ?
Check the lamp in the LCD module.
Replace the inverter PWB unit.
(No)
(Yes)
(No)
Is FB23 at DC+12V ?
Is CN10-5P at H level (DC+3.3V) ?
Check IC16 peripheral circuits.
Check BLON signal and CN10 peripheral
circuits.
circuits.
(No)
(Yes)
(No)
(Yes)
Check the analog signal cable, CN2
peripheral, and IC peripheral circuits.
peripheral, and IC peripheral circuits.
Is CN12-1P at DC+12V ? (LL-T1620H/B only)
Check IP4 and IC25 peripheral circuits.
(Yes)
(No)
Is CN9-39P at DC+5V ? (LL-T1520H/B only)
Check IP2 and IC25 peripheral circuits.
(No)
Are signals at IC13-17, 24, 40P normal ?
Are signals at R19 and R71 normal ?
Check CN2, IC5, and IC13 peripheral circuits.
2
3
(Yes)
(No)
Is the signal between IC13 and CN9,C11 normal ?
(LL-T1520H/B only)
(LL-T1520H/B only)
Check IC13, CN9, and 11 peripheral circuits.
(Yes)
(No)
Is the signal between IC13 and IC27 normal ?
(LL-T1620H/B only)
Check IC13 and IC27 peripheral circuits.
(Yes)
(No)
Is the signal between IC27 and CN12 normal ?
(LL-T1620H/B only)
Check IC27 and CN12K peripheral circuits.
(Yes)
(No)
Are the cables of the LCD unit normal ?
Check the cables and related parts.
(Yes)
Replace the LCD unit.
Display