Sony Trinitron KV-BT21M80 Service Manual page 6

5. HANDLING OF SELF-DIAGNOSTIC SCREEN DISPLAY
Since the diagnostic results displayed on the screen are not automatically cleared, always check the self-diagnostic
screen during repairs. When you have completed the repairs, clear the result display to "0".
Unless the result display is cleared to "0", the self-diagnosis function will not be able to detect subsequent faults after
completion of the repairs.
[Clearing the result display]
To clear the result display to "0", press buttons on the remote commander subsequent as shown below when the
self-diagnostic screen is being displayed.
8 , -
[Quitting Self-diagnostic screen]
To quit the entire self-diagnostic screen, turn off the power switch on the remote commander or the main unit.
6. SELF-DIAGNOSTIC CIRCUIT
A BOARD
Y/CHROMA JUNGLE
FROM
C BOARD 84 IK
IC751 PIN 5
A BOARD
FROM 32 EHTO
Q816
COLLECTOR
[+B overcurrent $OCP%]
[V-PROTECT]
[IK $AKB%]
POWER SUPPLY NG (+5V)
for VIDEO PROCESSOR
* (Refers to the RGB levels of the AKB detection Ref pulse that detects IK.)
A BOARD
IC001 IC804
V.OUT
3
F.B-PLS
Occurs when an overcurrent on the +B(135V) line is detected by pin 32 of IC001 (A board).
If the voltage of pin 32 of IC001 (A board) is more than 4V, the unit will automatically go to
standby.
Occurs when an absence of the vertical deflection pulse is detected by pin 13 of IC001
(A board).
If the RGB levels* do not balance within 15 sec after the power is turned on, this error will be
detected by IC001 (A board). TV will stay on, but there will be 5 times LED blinking.
Occurs when IC001 internal HV protect detects an abnormal H-Pulse (frequency) due to
improper power supply to IC001. TV cuts off high voltage power of anode CRT. No picture
will be detected. eg: IC602, IC604 go faulty.
A BOARD
IC001
SYSTEM
SDA1
13 99
V.GUARD
RED LED
122
– 5 –
KV-BT21M80
RM-W101
A BOARD
IC003
MEMORY
5
SDA
DISPLAY