Sony TRINITRON KV-27V42 Service Manual page 6

KV-27V42/27V66/29SL42K/29SL42T/29VL42T/29XL42T
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
Y/CHROMA JUNGLE
FROM
21
CRT
FROM
18
IC521
PIN 7
+B overcurrent (OCP)
Vertical deflection stopped
White balance failure
IC301 IC541
V. OUT
IK IN
REF
HP/PROTECT
SDA 35
Occurs when an overcurrent on the +B (115V) line is detected by pin 18 of IC301. If the voltage
of pin 18 of IC301 is less than 1V when V.SYNC is more than seven verticals in a period, the
unit will automatically turn off.
Occurs when an absence of the vertical deflection pulse is detected by pin 17 of IC001. Power
supply will shut down when waveform interval exceeds 2 seconds.
If the RGB levels* do not balance within 2 seconds after the power is turned on, this error will be
detected by IC301. TV will stay on, but there will be no picture.
*(Refers to the RGB levels of the AKB detection Ref pulse that detects 1K.)
IC001
SYSTEM
IO-BDAT
3 17 I-PROT
O-LED
37 IO-SDAT
— 6 —
IC003
MEMORY
36 5 B-DAT
18
DISPLAY