Read Sharp LC-37HV4E (serv.man8) Service Manual online
22
LC-37HV4E
Note that it is necessary to replace the unit when replacing the Config ROM for receiver (IC2202), receiver IC (IC2208) and HDCP key ROM
(IC2208). Have the relevant unit (DKEYHB453FE50) handy.
(IC2208). Have the relevant unit (DKEYHB453FE50) handy.
No image or sound comes out.
Is the power LED lit up
in green?
in green?
Is the power LED
flashing in red?
flashing in red?
YES
YES
NO
NO
Is the AC cord
normal?
normal?
NO
Is the backlight off?
Is "LOSS OF SYNC"
displayed?
displayed?
NO
Proceed to "No image
comes out".
comes out".
NO
Is it flashing once in
one cycle?
one cycle?
Proceed to "The backlight does
not light up".
not light up".
Is it flashing twice in
one cycle?
one cycle?
Check the power unit.
NO
Is it flashing five times
in one cycle?
in one cycle?
Check the connections between
the main unit and inverter 3 unit,
between the inverter 3 unit and
inverter 4 unit, and between the
inverter 4 unit and audio unit.
the main unit and inverter 3 unit,
between the inverter 3 unit and
inverter 4 unit, and between the
inverter 4 unit and audio unit.
YES
YES
YES
YES
YES
Is TP4302 about 0V or
is D4301 off?
is D4301 off?
Check IC2208 and the circuits
around it.
around it.
YES
Is there any problem around pins (104),
(106), (107) and (155) of IC4701, pins
(104), (106), (107) and (155) of IC4901,
IC4303 and IC4301?
(106), (107) and (155) of IC4701, pins
(104), (106), (107) and (155) of IC4901,
IC4303 and IC4301?
YES
Replace IC4301 and IC4303 or perform
writing to IC4303 and IC4301 using the
special writing jig.
writing to IC4303 and IC4301 using the
special writing jig.
Check the circuits around them.
NO
Replace the AC
NO
LED flashing timing list
Error type
LED behavior (1 cycle)
Cable error
H: ON
AVC-side power error
L: OFF
H: ON
1S
Lamp error
L: OFF
250ms
H: ON
Monitor power error
L: OFF
H: ON
AVC temperature error
L: OFF
H: ON
AVC FAN error
L: OFF
H: ON
Monitor temperature
error
error
L: OFF
TROUBLE SHOOTING TABLE
23
LC-37HV4E
Dropout (relating to gray scale)
Set PATTERN1 under
PATTERN on the adjustment
process menu to "2". Is the
gray scale pattern displayed
properly?
PATTERN on the adjustment
process menu to "2". Is the
gray scale pattern displayed
properly?
Send "6071" and "6303" to
LCD DATA under OTHER on
the adjustment process
menu to display the QS drive
test pattern and then send
"6102". Is the gray scale
displayed properly?
LCD DATA under OTHER on
the adjustment process
menu to display the QS drive
test pattern and then send
"6102". Is the gray scale
displayed properly?
Identify the colour signal
presenting a problem in the gray
scale test pattern.
presenting a problem in the gray
scale test pattern.
Is there any problem with the
connections and resistances
between IC4501 and SC4601-
SC4604?
between IC4501 and SC4601-
SC4604?
YES
YES
YES
NO
NO
Check IC4501 and
SC4601-SC4604.
SC4601-SC4604.
Check IC4702, IC4902
and the circuits around
them.
and the circuits around
them.
NO
Send "6202" to LCD DATA
under OTHER on the
adjustment process menu. Is
the test pattern displayed
properly at intervals of one
dot?
under OTHER on the
adjustment process menu. Is
the test pattern displayed
properly at intervals of one
dot?
Check the connections
between IC4701 and
IC4501.
between IC4701 and
IC4501.
NO
NO
YES
YES
Send "6203" to LCD DATA
under OTHER on the
adjustment process menu. Is
the test pattern displayed
properly at intervals of one
dot?
under OTHER on the
adjustment process menu. Is
the test pattern displayed
properly at intervals of one
dot?
Check the connections
between SC2201 and
IC2206, between IC2206 and
IC4701, and between IC2206
and IC4901.
between SC2201 and
IC2206, between IC2206 and
IC4701, and between IC2206
and IC4901.
Check the connections
between IC4901 and
IC4501.
between IC4901 and
IC4501.
Check the FFC
connected to SC4601-
SC4604.
connected to SC4601-
SC4604.
YES
YES
YES
No image comes out.
Is a HIGH appearing
at the RESET terminal
of pin (3) of IC2206?
at the RESET terminal
of pin (3) of IC2206?
Check the circuits
around X2201
connected to pin (161)
of IC2206.
around X2201
connected to pin (161)
of IC2206.
NO
Check IC4903 and later
ICs (IC4701, IC4702,
IC4901 and IC4902).
ICs (IC4701, IC4702,
IC4901 and IC4902).
Is a clock (91.3 MHz)
appearing at TL2201
(pin (102) of IC2206)?
appearing at TL2201
(pin (102) of IC2206)?
Is X2201 connected to pin
(161) of IC2206 oscillating
(18.26MHz)?
(161) of IC2206 oscillating
(18.26MHz)?
NO
Check X2201 and the
circuits around it.
circuits around it.
NO
YES
YES
Is a normal sync
signal appearing at
TL2202 (pin (97) of
IC2206), TL2203 (pin
(96) of IC2206) and
TL2204 (pin (95) of
IC2206)?
signal appearing at
TL2202 (pin (97) of
IC2206), TL2203 (pin
(96) of IC2206) and
TL2204 (pin (95) of
IC2206)?
Is IC2202 (CONFIG ROM)
operating?
operating?
Failure of IC2206
NO
Check IC2202 and the
circuits around it.
circuits around it.
NO
TROUBLE SHOOTING TABLE (Continued)
24
LC-37HV4E
Noise appears on the moving image when the QS drive is turned ON.
Is OSTEMP.AD on the 3rd page
of the process adjustment
mode set to 255?
of the process adjustment
mode set to 255?
Are the audio unit and the
inverter 4 unit connected
properly by the harness?
inverter 4 unit connected
properly by the harness?
YES
Are the inverter 3 unit and the
inverter 4 unit connected
properly by the board-to-board?
inverter 4 unit connected
properly by the board-to-board?
YES
NO
Check IC4701, IC4901 and
the circuits around them.
the circuits around them.
NO
Check IC4701, IC4901 and
the circuits around them.
the circuits around them.
NO
Connect securely or replace
the board-to-board.
the board-to-board.
Are the main unit and the
inverter 3 unit connected
properly by the harness?
inverter 3 unit connected
properly by the harness?
YES
NO
Connect properly or replace
the harness.
the harness.
Is the input voltage at pin (2) of
IC2004 (micro-processor) 5V?
IC2004 (micro-processor) 5V?
YES
Failure of thermistor of TH3801.
YES
NO
Failure of pin (2) of IC2004
(micro-processor).
(micro-processor).
The backlight does not light up.
Is any of the fuses of
F7501- F7504, F7551-
F7553, F7611-F7614 and
F7641-F7643 burned out?
F7501- F7504, F7551-
F7553, F7611-F7614 and
F7641-F7643 burned out?
Check the inverter circuit
downstream from the
burned-out fuse.
downstream from the
burned-out fuse.
YES
YES
NO
Is a control signal
appearing at pin (2)
(OFL1) and pin (3) (OFL2)
of P7506 and P7616?
appearing at pin (2)
(OFL1) and pin (3) (OFL2)
of P7506 and P7616?
Is power supplied to each
unit?
unit?
Check the opposite
inverter circuit of the pair.
inverter circuit of the pair.
Check the wire connected between the inverter 1 and 3 units, the board-
to-board between the inverter 1 and 2 units and the board-to-board
between the inverter 3 and 4 units.
to-board between the inverter 1 and 2 units and the board-to-board
between the inverter 3 and 4 units.
Check for 15V output in the power
unit.
unit.
Check the connection of the
high-voltage (pin 2) wire on the
side of the burned-out fuse and
check the connection of the high-
voltage (pin 2) wire of the
opposite fluorescent lamp of the
pair.
high-voltage (pin 2) wire on the
side of the burned-out fuse and
check the connection of the high-
voltage (pin 2) wire of the
opposite fluorescent lamp of the
pair.
NO
NO
Are the main unit and the inverter
1 and 3 units connected properly
by the harness.
1 and 3 units connected properly
by the harness.
YES
YES
Check the circuits around IC4501
in the main unit and check the
operation of Q7704 and Q7705.
in the main unit and check the
operation of Q7704 and Q7705.
TROUBLE SHOOTING TABLE (Continued)
25
LC-37HV4E
No sound comes out. (Connect to the AVC System and check.)
Is power supplied to each
IC in the audio unit?
IC in the audio unit?
Is an audio signal appearing
at pin (8) (L-IN) and pin (10)
(R-IN) of P3802?
at pin (8) (L-IN) and pin (10)
(R-IN) of P3802?
YES
Is an audio signal appearing
at pins (10) and (14) of
IC3812 (Audio Output)?
at pins (10) and (14) of
IC3812 (Audio Output)?
YES
YES
YES
YES
NO
Check around the
power regulator circuit
(IC3809, IC3810).
power regulator circuit
(IC3809, IC3810).
NO
Is an audio signal
appearing at pins (13)
and (20) of SC2202 in
the main unit?
appearing at pins (13)
and (20) of SC2202 in
the main unit?
NO
NO
Are Q3812 and Q 3813
(MUTE Circuits)
operating?
(MUTE Circuits)
operating?
Is an audio signal appearing
at pins (24), (27), (28) and
(31) of IC3812 (Audio
Output)?
at pins (24), (27), (28) and
(31) of IC3812 (Audio
Output)?
YES
Check if RY3801 (for
Internal/External switching) is
operating properly.
Internal/External switching) is
operating properly.
NO
NO
Check D3828-D3831
for short-circuiting and
check the circuits
around IC3812.
for short-circuiting and
check the circuits
around IC3812.
NO
Check IC3801, IC3803,
IC3804-IC3807, and
IC3811 for I/O signals.
IC3804-IC3807, and
IC3811 for I/O signals.
Check around Q2012 and Q2014 and check the
wire connected between the main unit and
audio unit.
wire connected between the main unit and
audio unit.
The whole screen is whitish (LCD power supply)
Disconnect the FFC from CN4101,
CN4102 and CN4601-CN4604.
(Otherwise it may cause the panel to get
broken.)
CN4102 and CN4601-CN4604.
(Otherwise it may cause the panel to get
broken.)
Check the power supplies.
Check the power supplies to CN4101
and CN4102 in particular.
Check the power supplies to CN4101
and CN4102 in particular.
YES
Is the voltage of R4114 around 6V?
YES
Check the I/O voltages of IC4103,
IC4105 and IC4106.
IC4105 and IC4106.
Check the performance of Q4101
and Q4112 and check the
resistances around IC4102.
and Q4112 and check the
resistances around IC4102.
TROUBLE SHOOTING TABLE (Continued)
