JVC AV-29L6SU, AV-29L6BU, Service Manual

Page: 28 / 60

1-28 (No.YA366)
SECTION 5
TROUBLESHOOTING
5.1 SELF CHECK FUNCTIONS
5.1.1 OUTLINE
These models have self-check functions given below. When an abnormality has been detected, the SUB POWER is turned off and
POWER LED is blinking. An abnormality is detected by the signal input state of the control line connected to the microcomputer.
5.1.2 SELF CHECK ITEMS
5.1.3 SELF CHECK INDICATING FUNCTION
When an abnormality has been detected at about 5 seconds
after the power is turned on, the SUB POWER is turned off
immediately and the POWER LED begins blinking.
Check item Details of detection Method of detection State of abnormality
Low B short protection A short on the low B (1.8V,
3.3V) line is detected. The protect port on the
microcomputer (100pin) is always
monitored at 10msec intervals. If
an abnormality is detected 75 times
successively, it is judged that there
is an abnormality. When an abnormality has detected,
the SUB POWER is turned off and
POWER LED lis blinking. While the
SUB POWER is being turned off,
the POWER key on the remote
control unit is not operational until
the power cord is taken out and put
in again.
CRT neck broken protection Operation of CRT neck broken
protection circuit.
(Vertical amplitude is detected.)
DITTO DITTO
X-ray protection The rise of a high voltage value
is detected. DITTO DITTO
After about
5 seconds
Power on
Start of
detection
Detection of
an abnormality
SUB-POWER OFF
Blinking the POWER LED