JVC AV-34WP84 /ZA Service Manual page 49

5.1 SELF-DIAGNOSIS FEATURE
5.1.1 OUTLINE
This unit comes with the "Self-diagnosis" 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.
5.1.2 HOW TO ENTER THE SELF-DIAGNOSIS MODE
(1) Press the [SLEEP TIMER] key of the remote control unit
and set the SLEEP TIMER 30 MIN.
(2) While it is being displayed, press the [DISPLAY] key and
[VIDEO STATUS] key simultaneously.
(3) The TEST MODE screen is displayed.
(4) Press the [4] key.
The self-diagnosis screen is displayed.
5.1.3 HOW TO EXIT THE SELF-DIAGNOSIS MODE
Other exit from the SELF-DIAGNOSIS.
WITH INITIALIZATION
By using the remote controller unit, turn the power off.
At this time, the failure record is cleared.
WITH NOT INITIALIZATION
Take off the AC plug from the wall outlet. At this time, the
failure record is not cleared.
5.1.4 FAILURE HISTORY
The latest failure is stored on the record at the end.
The failure record for each check item is counted to the number
of 9 at the maximum.
Only SYNC is not counted and memorized.
5.1.5 POINTS TO NOTE WHEN USING THE SELF-DIAGNOSIS 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 I
• Because of the timing of Vcc start-up and shutdown of the IC connecting to the I
the operation may be interpreted as an error. In order to avoid the misinterpretation, the self- diagnosis functions should be started
at about 3 seconds after the power is turned on.
If recurrences are expected, ensure to clear (reset) the failure history and record the new diagnosis results.
SECTION 5
TROUBLESHOOTING
2
C bus (Vcc) when turning on/off the main power.
TEST MODE SCREEN
TEST MODE
1. I2C STOP
2. STATUS DISP.
4. SELF-CHK
5. CONVER OFF
ROM CORRECCTION : PAS
ROM VER. : MN102H75KES
Fig.1
S
XRAY OK OCP OK
LOB OK TIM OK
SYNC M : OK S : NG HD : NG
MEN OK AVSW OK
VCD OK
AIO OK YC OK
TUN OK
PP OK IP OK
HDMI OK
Fig.2
2
C bus during which the power is turned on and off,
8618
DO NOT OPEN
(No.52170)1-49