Troubleshooting - JVC LT-52GZ79 Service Manual

5.1 SELF CHECK FEATURE
5.1.1 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 I
the various control lines connected to the main microcomputer.
5.1.2 HOW TO ENTER THE 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 [DISPLAY]
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.
*Use the [GREEN] key to toggle between Page 1 and Page 2.
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. Press the
[MENU] key to return to the MAIN MENU SCREEN.
5.1.3 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.
5.1.4 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.
1-20 (No.YA665<Rev.001>)
SECTION 5

TROUBLESHOOTING

2
C bus and
key and [MUTING] key
5.1.5 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 counted.
(1) Temporary defective transmissions across circuits due to
pulse interruptions.
(2) Misalignment in the on/off timing of power for I
when turning on/off the main power.
Therefore, turn on the main power, and then wait for about 3
seconds before starting Self check.
If recurrences are expected, ensure to clear (reset) the failure
history and record the new diagnosis results.
SERVICE MENU SCREEN
SERVICE MENU SERVICE MENU
1. ADJUST 1. ADJUST
2. SELF CHECK 2. SELF CHECK
3. I2C STOP 3. I2C STOP
Press [2] key
SELF CHECK MODE SCREEN (Page 1)
Failure
Item
history
LOB LOB 0 0
AUD AUD 0 0
ANA ANA 9 9
HOUR HOUR 131070 131070
Press [Red] key
SELF CHECK MODE SCREEN (Page 2)
TMP TMP 0 0
L 2 L 2 0 0
FAN FAN 0 0
IRS IRS 0 0
2
C bus (Vcc)
Failure
Item
history
FAN FAN 0 0
DIG DIG 9 9
MAX MAX 00 00
00 00
Press [Green] key
Not used
L 1 L 1 0 0
DDT DDT 0 0
L C L C 0 0
Fig.5-1