Saturday, August 29, 2015

JVC LT-Z26SX5 LT-Z32SX5 SERVICE MODE AND POWER SUPPLY CIRCUIT

JVC LT-Z26SX5 LT-Z32SX5 

SERVICE MODE AND POWER SUPPLY CIRCUIT 

MEMORY IC REPLACEMENT
# This model uses the memory IC.
# This memory IC stores data for proper operation of the video and drive circuits.
# When replacing, be sure to use an IC containing this (initial value) data.
EMORY IC REPLACEMENT PROCEDURE
1. Power off
Switch off the power and disconnect the power plug from the AC outlet.
2. Replace the memory IC
Be sure to use the memory IC written with the initial setting values.
3. Power on
Connect the power plug to the AC outlet and switch on the power.
4. Receiving channel setting
Refer to the OPERATING INSTRUCTIONS and set the receive channels (Channels Preset) as described.
5. User setting
Check the user setting items according to the given in page later. Where these do not agree, refer to the OPERATING INSTRUCTIONS and set the items as described.
6. SERVICE MODE setting
Verify what to set in the SERVICE MODE, and set whatever is necessary.
ADJUSTMENT PREPARATION
(1) There are 2 ways of adjusting this TV : One is with the REMOTE CONTROL UNIT and the other is the conventional method using adjustment parts and components.
(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 warning 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.
ADJUSTMENT ITEMS
VIDEO CIRCUIT
# 625i A-D OFFSET adjustment
# 1125i(50Hz) BRIGHTNESS adjustment
# 1125i(50Hz) A-D OFFSET adjustment
# SUB SCREEN A-D OFFSET adjustment
# WHITE BALANCE (HIGH LIGHT) adjustment.

SERVICE MODE 
HOW TO ENTER THE SERVICE MODE
(1) Press [DISPLAY] key and [MUTING] key on the remote control unit simultaneously to enter the SERVICE MODE SCREEN.
(2) In the SERVICE MENU, press the [1] key to display ADJUSTMENT MODE SCREEN.
NOTE:
# Before entering the SERVICE MODE, confirm that the setting of PIP/TV/DVD switch is at the "TV" side. If the switches have not been properly set, you cannot enter the SERVICE MODE.
# When a number key other than the [1] to [3] key is pressed in the SERVICE MODE SCREEN, the other relevant screen may be displayed. This is not used in the adjustment procedure. Press the [MENU] key to return to the SERVICE MODE SCREEN.
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 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. But, don't change the values that are not written in "ADJUSTMENT PROCEDURE". They are fixed values.
SELF CHECK FEATURE OUTLINE
This 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.
HOW TO ENTER THE SELF CHECK MODE
Before entering the SERVICE MODE, confirm that the setting of PIP/TV/ DVD switch is at the "TV" side. If the switches have not been properly set, you cannot enter the SERVICE MODE.
(1) Press [DISPLAY] key and [MUTING] key simultaneously, then enter the SERVICE MODE.
(2) Press the [2] key SELF CHECK MODE.
(3) Press the [ZOOM] key to enter Page 2 of the SELF CHECK MODE. *Use the [CINEMA] key to toggle between Page 1 and Page 2.
NOTE: When a number key other than the [1] to [3] key is pressed in the SERVICE MODE screen, the other relevant screen may be displayed. This is not used in the adjustment procedure. Press the [MENU] key to return to the MAIN MENU SCREEN.
HOW TO EXIT THE 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 THE 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".
(1) Temporary defective transmissions across circuits due to pulse interruptions
(2) 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 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.

TECHNICAL INFORMATION
LCD PANEL
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.

POWER SUPPLY CIRCUIT 

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