JVC LT-42P789/C - LT-47P789/C SERVICE MODE AND POWER SUPPLY CIRCUIT
MEMORY IC REPLACEMENT PROCEDURE
1. Power off
Switch off the power and disconnect the power plug.
2. Replace the memory IC
Be sure to use a memory IC written with the initial setting data.
3. Power on
Connect the power cord to the wall outlet and switch on the power.
4. Receiving channel setting
Refer to the OPERATING INSTRUCTIONS (USER'S GUIDE)
and set the receive channels (Channels Preset) as described.
5. User settings
Check the user setting items according to the "FACTORY
SETTING ITEM" table.
Where these do not agree, refer to the OPERATING INSTRUCTIONS (USER'S GUIDE)
and set the items as described.
6. SERVICE MODE setting
Verify what to set in the SERVICE MODE
ADJUSTMENT PREPARATION
(1) This TV is adjusted by using REMOTE CONTROL UNIT.
(2) The adjustment using the REMOTE CONTROL UNIT is made on the basis of the
initial setting values. The setting values which adjust the screen to the
optimum condition can be different from the initial setting values.
(3) Make sure that connection is correctly made AC to AC power source.
(4) Turn on the power of the TV and measuring instruments for warming up for at
least 30 minutes before starting adjustments.
(5) If the receive or input signal is not specified, use the most appropriate
signal for adjustment.
(6) Never touch the parts (such as variable resistors, transformers and
condensers) not shown in the adjustment items of this service adjustment.
SERVICE MODE
HOW TO ENTER THE SERVICE MODE
(1) Set to "OFF" using the [SLEEP] key.
(2) While "OFF" is displayed, press the [V. STATUS] key and [DISPLAY]
key simultaneously.
(3) Enter the SERVICE MODE
(4) Select the 2.White balance base from the SERVICE MODE.
HOW TO EXIT THE SERVICE MODE
Press the [MENU] key to exit the SERVICE MODE.
INITIAL SETTING VALUES IN THE SERVICE
MODE
• Perform fine-tuning based on the "initial values" using the remote
control unit when in the SERVICE MODE.
• The "initial values" serve only as an indication rough standard and
therefore the values with which optimal display can be achieved may be different from the default values.
WHITE BALANCE
(HIGHLIGHT)
(1) Receive a NTSC
75% all white signal.
(2) Set "VIDEO STATUS" to "Standard".
(3) Set "ASPECT" to "Full".
(4) Select "COLOR TEMP" to "Natural".
(5) Select the 2.White balance base from the SERVICE MODE.
(6) Set the setting value of <R Offset>(Red Offset), <G Offset>(Green
Offset) and <B Offset>(Blue Offset) to 0.
(7) Adjust to keep one of <R Gain>(Red Gain), <G Gain>(Green Gain)
or <B Gain>(Blue Gain) unchanged, then lower the other two so that the
all-white screen is equally white throughout.
NOTE: Set one or more of <R Gain>, < G Gain> and <B Gain> to "0".
(8) Check that white balance is properly tracked from low light to high light.
If the white balance tracking is deviated, adjust to correct it.
SELF CHECK FUNCTIONS
OUTLINE
This model has a self check function given below. When an abnormality has been
detected, the power is turned off and the POWER
LED flashes to inform of the failure. An abnormality is detected by the signal
input state of the control line connected to the microcomputer.
METHOD OF DISPLAY
WHEN A RASTER IS NOT OUTPUT
In the state where a raster is not output by breakdown of the set, an error is
displayed by blink of the POWER LED.
<Explanation of
operation>
If an error is detected, the power is turned off. Shortly after the power is
turned off, the POWER LED will be blinked. Power cannot be turned on until the
power cord takes out and inserts, after the power is turned off.
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.
POWER SUPPLY CIRCUIT
LT-42P789/C
LT-47P789/C
CLICK ON THE IMAGE TO ZOOM IN
1. Power off
Switch off the power and disconnect the power plug.
2. Replace the memory IC
Be sure to use a memory IC written with the initial setting data.
3. Power on
Connect the power cord to the wall outlet and switch on the power.
4. Receiving channel setting
Refer to the OPERATING INSTRUCTIONS (USER'S GUIDE)
and set the receive channels (Channels Preset) as described.
5. User settings
Check the user setting items according to the "FACTORY
SETTING ITEM" table.
Where these do not agree, refer to the OPERATING INSTRUCTIONS (USER'S GUIDE) and set the items as described.
6. SERVICE MODE setting
Verify what to set in the SERVICE MODE
(1) This TV is adjusted by using REMOTE CONTROL UNIT.
(2) The adjustment using the REMOTE CONTROL UNIT is made on the basis of the initial setting values. The setting values which adjust the screen to the optimum condition can be different from the initial setting values.
(3) Make sure that connection is correctly made AC to AC power source.
(4) Turn on the power of the TV and measuring instruments for warming up for at least 30 minutes before starting adjustments.
(5) If the receive or input signal is not specified, use the most appropriate signal for adjustment.
(6) Never touch the parts (such as variable resistors, transformers and condensers) not shown in the adjustment items of this service adjustment.
HOW TO ENTER THE SERVICE MODE
(1) Set to "OFF" using the [SLEEP] key.
(2) While "OFF" is displayed, press the [V. STATUS] key and [DISPLAY] key simultaneously.
(3) Enter the SERVICE MODE
(4) Select the 2.White balance base from the SERVICE MODE.
Press the [MENU] key to exit the SERVICE MODE.
• Perform fine-tuning based on the "initial values" using the remote control unit when in the SERVICE MODE.
• The "initial values" serve only as an indication rough standard and therefore the values with which optimal display can be achieved may be different from the default values.
(HIGHLIGHT)
(2) Set "VIDEO STATUS" to "Standard".
(3) Set "ASPECT" to "Full".
(4) Select "COLOR TEMP" to "Natural".
(5) Select the 2.White balance base from the SERVICE MODE.
(6) Set the setting value of <R Offset>(Red Offset), <G Offset>(Green Offset) and <B Offset>(Blue Offset) to 0.
(7) Adjust to keep one of <R Gain>(Red Gain), <G Gain>(Green Gain) or <B Gain>(Blue Gain) unchanged, then lower the other two so that the all-white screen is equally white throughout.
NOTE: Set one or more of <R Gain>, < G Gain> and <B Gain> to "0".
(8) Check that white balance is properly tracked from low light to high light. If the white balance tracking is deviated, adjust to correct it.
OUTLINE
This model has a self check function given below. When an abnormality has been detected, the power is turned off and the POWER
LED flashes to inform of the failure. An abnormality is detected by the signal input state of the control line connected to the microcomputer.
In the state where a raster is not output by breakdown of the set, an error is displayed by blink of the POWER LED.
If an error is detected, the power is turned off. Shortly after the power is turned off, the POWER LED will be blinked. Power cannot be turned on until the power cord takes out and inserts, after the power is turned off.
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.
