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.

1. Press the [INFORMATION] key and [MUTING] key simultaneously, then enter the SERVICE MODE.
2. Press the [2] key SELF CHECK MODE.
3. Press the [RED] key to enter Page 2 of the SELF CHECK MODE.
4. Use the [GREEN] key to toggle between Page 1 and Page 2.
5. 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.

1. Low bias line short protection => Blue turning on and off at 1 second intervals.
2. 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