JVC LT-46Z70BU _ SERVICE MODE _ SELF CHECK MODE & DESCRIPTIONS OF FAULT
TO ENTER SERVICE MODE
- Press the [INFORMATION] key and [MUTING] key simultaneously, then enter the SERVICE MODE.
- When the Main Menu is displayed, press [2] key to enter the self check mode.
- Turn off the power by pressing the [POWER] key on the remote control unit.
LCD PANEL INFORMATION
This unit uses the flat type panel LCD
(Liquid Crystal Display) panel that occupies as little space as possible,
instead of the conventional CRT (Cathode Ray Tube), as a display unit.
Since
the unit has the two polarizing filter that are at right angles to each other,
the unit adopts "normally black" mode, where light does not pass
through the polarizing filter and the screen is black when no voltage is
applied to the liquid crystals.
PIXEL FAULT: There are three pixel faults - bright fault ,
dark fault and flicker fault - that are respectively defined as follows
BRIGHT FAULT
In this pixel fault, a cell that
should not light originally is lighting on and off. For checking this pixel fault, input ALL BLACK SCREEN and find out
the cell that is lighting on and off.
DARK FAULT
In this pixel fault, a cell that should light
originally is not lighting or lighting with the brightness twice as brighter as
originally lighting. For checking this
pixel fault, input 100% of each R/G/B color and find out the cell that is not
lighting.
FLICKER FAULT
In the pixel fault, a cell that should
light originally or not light originally is flashing on and off. For checking this pixel fault, input ALL
BLACK SCREEN signal or 100% of each RGB color and find out the cell that is
flashing on and off.
TROUBLESHOOTING
Unit comes with the "Self
check" feature, which checks the operational state of the circuit and
displays/saves it during failure. Diagnosis is performed when power is turned
on, and information
input to the main microcomputer is monitored at all time. Diagnosis is
displayed in 2 ways via screen display and LED flashes. Failure detection is
based on input state of I2C bus and the various
control lines connected to the main microcomputer.
TO ENTER SELF-CHECK MODE
Before enter the SELF CHECK MODE,
press the [MODE] key to confirm that "TV"
position is indicated. If it is in a wrong position, the SELF CHECK MODE
operation cannot be performed.
- Press the [INFORMATION] key and [MUTING] key simultaneously, then enter the SERVICE MODE.
- Press the [2] key SELF CHECK MODE.
- Press the [RED] key to enter Page 2 of the SELF CHECK MODE.
- Use the [GREEN] key to toggle between Page 1 and Page 2.
- Press the [MENU] key to return to the MAIN MENU SCREEN.
NOTE: When a number key other than the [2] key is pressed in the SERVICE MODE screen, the other relevant screen may be displayed. This is not used in the SELF CHECK MODE.
TO EXIT SELF-CHECK MODE
- To Save Failure History: Turn off the power by unplugging the AC power cord plug when in the Self check display mode.
- To Clear (Reset) Failure History: Turn off the power by pressing the [POWER] key on the remote control unit when in the Self check display mode.
FAILURE HISTORY
Failure history can be counted up to 9 times for
each item. When the number exceeds 9, display will remain as 9. Failure history
will be stored in the memory unless it has been deleted. NOTE: Only
SYNC (with/without sync signals) will be neither counted nor stored.
POINTS TO NOTE WHEN USING SELF CHECK FEATURE
- In addition to circuit failures (abnormal operation), the following cases may also be diagnosed as "Abnormal" and displayed and counted as "NG". [Not Good]
- Temporary defective transmissions across circuits due to pulse interruptions.
- Misalignment in the on/off timing of power for I2C bus (VCC) when turning on/off the main power. Diagnosis may be impeded if a large number of items are displayed as "NG". As such, start Self check only after 3 seconds in the case of receivers and 5 seconds in the case of panels upon turning on the power. If recurrences are expected, ensure to clear (reset) the failure history and record the new diagnosis results.
METHOD OF DISPLAY, WHEN RASTER IS ABSENT
In the state where a raster is not
output by breakdown of the set, an error is displayed by blink of the POWER
LED.
- Low bias line short protection => Blue turning on and off at 1 second intervals.
- Abnormal rise of temperature in audio circuit => Blue turnig on and off at 0.5 second intervals.
EXPLANATION OF OPERATION
- If error is detected, the power is turned off.
- Shortly after a power is turned off, POWER LED will be blinked.
- Power cannot be turned on until the power cord takes out and inserts, after a power is turned off.
SELF CHECK DISPLAY AND FAULT CHART: PAGE-1
Detection item
|
Display
|
Detection content
|
Diagnosis signal line
|
Detection timing
|
Low bias line short
Protection.
|
LOB
|
Confirm the operation of the low bais
(16V / 5V /
LCD5V / 3.3V / 1.2V) protection circuit. Q9601, Q9651[DC-DC PWB]
|
LB_PRO
|
Detection starts 3 seconds after
the power is turned on. If error
continues between 200 ms the power
is turned off.
|
Fan lock
|
FAN
|
NOT USED
|
------------
|
-------------
|
Abnormal rise of temperature in audio circuit
|
AUD
|
Confirmation of the temperature of audio
circuit.
TH6401 [D-AMP
PWB]
|
--------------
|
Detection starts 3 seconds after the
power is turned on. If the Temperture of 90°C is detected for 3 seconds the
power is turned off.
|
Devices on the ANALOG
PWB
|
ANA
|
Confirmation of reply of ACK signal which
uses I2C communication.
IC101, IC102, IC381, IC601, IC606, TU3002
[ANALOG PWB]
|
SDA
|
If it checks whenever I2C
communication is performed and no reply of ACK signal an error will be counted.
|
Devices on the DIGITAL
PWB
|
DIG
|
Confirmation of reply of ACK signal which
uses I2C Communication.
IC6401 [DIGITAL
PWB]
|
SDA
|
If it checks whenever I2C
communication is performed and no reply of ACK signal an error will be counted.
|
PAGE-2
Detection item
|
Display
|
Detection content
|
Temp. sensor
|
TEM
|
Not used
|
Lamp does not light up
|
L1
|
Not used
|
Lamp goes out
|
L2
|
Not used
|
Abnormal DD CPU
circuit
|
DDT
|
Not used
|
Fan lock
|
FAN
|
Not used
|
Lamp cover open
|
LC
|
Not used
|
Abnormal of optical iris
|
IRS
|
Not used
|
