JVC LT-26A80SU Service Manual page 23

5.1.6 DETAILS
Self check is performed for the following items:
<Page 1 of screen>
Detection item Display
Low bias line short LOB
protection
MAIN MEMORY MEM
AUDIO AIO
RF (ANALOG) TUNER TUN
HDMI HDM
<Page 2 of screen> indicates items not used for services as they are for designing.
Detection item Display
SYNC SIGNAL SYN
For designing CDN
For designing ADS
For designing ADH
For designing PPL
For designing LPF
5.1.7 METHOD OF DISPLAY WHEN A RASTER IS NOT OUTPUT
In the state where a raster is not output by breakdown of the set, an error is displayed by blink of the POWER LED.
Type of error
Low bias line short protection
MAIN CPU error detection
< Explanation of operation >
If error is detected, the power is turned off. Shortly after the power is turned off, POWER LED will be blinked.
When the protection of low bias line short operates, the power cannot be turned on until the power cord takes out and inserts, after
the power is turned off.
Detection content
Confirm the operation of the low bais(5V/12V/
13.5V/14V) protection circuit.
5V: Q9201 [MAIN PWB]
12V: Q9301 [MAIN PWB]
13.5V: Q9505 [POWER PWB]
14V: Q9503 [POWER PWB]
Confirmation of reply of ACK signal which uses
2
I C communication.
IC7003 [MAIN PWB]
Not used
Confirmation of reply of ACK signal which uses
2
I C communication.
TU1001 [MAIN PWB]
Confirmation of reply of ACK signal which uses
2
I C communication.
Detection content
Confirmation of presence of sync signal in
selected video signal.
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Red turnig on and off at 1 second intervals.
Red turnig on and off at 2 second intervals.
Diagnosis
signal (line)
LB_PRO Detection starts 5 seconds after
the power is turned on. If error
continues between 200 ms the
power is turned off.
SDA If
communication is performed and
no reply of ACK signal an error
will be counted.
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SDA If
communication is performed and
no reply of ACK signal an error
will be counted.
SDA If
communication is performed and
no reply of ACK signal an error
will be counted.
Detection timing
The selected video input signal is always
checked and if there is the sync signal, it is
displayed as "OK", and if not as "NG".
POWER LED flash cycle
Detection timing
2
it checks whenever I C
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2
it checks whenever I C
2
it checks whenever I C
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(No.YA509)1-23