Sony KV-21FE13 Service Manual page 7

Self-Diagnostic Screen Display
For errors with symptoms such as "power sometimes shuts off" or "screen sometimes goes out" that cannot be confi rmed, it is possible to bring up
past occurrences of failure on the screen for confi rmation.
To Bring Up Screen Test
In standby mode, press buttons on the Remote Commander sequentially, in rapid succession, as shown below:
Display
Channel 5
Self-Diagnostic Screen Display
SELF DIAGNOSTIC
2: 000
3: N/A
4: 000
Numeral "0" means that no fault was detected.
5: 001 Numeral "1" means a fault was detected one time only.
101: N/A
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-diagnostic 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 sequentially when the diagnostic screen is displayed, as shown below:
Channel 8 ENTER
Quitting the Self-Diagnostic Screen
To quit the entire self-diagnostic screen, turn off the power switch on the Remote Commander or the main unit.
Self-Diagnostic Circuit
MB BOARD
Y/CHROMA JUNGLE
FROM
CB BOARD
21
IK IN
IC702 PIN 5
A BOARD
18
HP/PROTECT
FROM
IC501
PIN 3
+B overcurrent (OCP)
Occurs when an overcurrent on the +B (135V) line is detected by pin 18 of IC1301 (MB Board). If the voltage of pin 18 of IC1301 (MB Board) is less
than 1V when V.SYNC is more than seven verticals in a period, the unit will automatically turn off.
I-Prot
Occurs when an absence of the vertical defl ection pulse is detected by pin 17 of IC1001 (MB Board). Power supply will shut down when waveform
interval exceeds 2 seconds.
IK (AKB)
If the RGB levels* do not balance within 2 seconds after the power is turned on, this error will be detected by IC1301 (MB Board). TV will stay
on, but there will be no picture.
*(Refers to the RGB levels of the AKB detection Ref pulse that detects 1K).
Sound Volume -
Power ON
Note that this differs from entering the Service Mode (Sound Volume + ).
A BOARD
IC502
IC1301
V. OUT
REF
35
SDA
MB BOARD
IC1001
SYSTEM
IO-BDAT
3
17
I-Prot
O-LED
37
IO-SDAT
— 7 —
KV-21FE13 / 21FE13C / 21FM13 / 21FM13C
MB BOARD
IC1003
MEMORY
36
5 BDA
18
DISPLAY