Sony KDL-40EX725 Service Manual page 40

The first thing to check when a 3X blink protection mode occurs is
the physical condition of the speakers and speaker connections. The
speakers should measure 8 ohms. Shorted speakers or connections
can cause a 3X blink protection mode.
If the speakers and connections check okay, then the defective
component is on the Main Board. Either an open F4200, defective
DC Regulator, or defective Audio amplifier will cause a 3X blink
protection mode. In any of these cases, replace the Main Board to
fix this condition.
A defect on the Power Supply Board can cause a 3X blink protection
mode and shut-off. Check the AU12V level at CN6704/pin 14. If 0V is
measure before shut-off the Power Supply Board is defective.
4X Blink – Balancer Error
The 4X error code is only used on models incorporating local dimming
LED backlighting. If a failure occurs on the LD board the TV will shut
down and display this diagnostic code. Models using conventional
non-local dimming LED backlighting do not utilize this error code.
5X Blink - TCON Error
The 5X blink protection mode indicates a communications error
between the TCON Board and the X-Reality microprocessor on the
Main Board. If the TCON is available for replacement, replace the
TCON. If the TCON is not available, the LCD panel must be replaced
since the TCON circuit is part of the LCD panel assembly. In rare
cases a loose or defective LVDS cable could also be the cause.
KDL-32EX725/40EX725/46EX725/55EX725
SECTION 4 - TROUBLESHOOTING
6X Blink - Backlight System Failure
NOTE: All models will make two attempts to power up before a 6X is
activated. The SONY logo (Backlight) may or may not display on the
screen. However, the splash tones will be heard two times. After the
second attempt the TV will turn off and the standby LED will blink a
6X protection mode. (Note: The splash tone may not be heard if it is
turned off or the volume is set to minimum.)
If a 6X blink pattern is activated then a defect has occurred in one of
the following areas.
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When troubleshooting a 6X backlight system failure it is key to notice
if the backlights illuminate before the TV shuts off. The following
list shows the possible backlight status and blink pattern and the
possible failed components.
1) Momentary Backlight and 6X
a) Defective LED(s) (LCD Panel Assb.)
2) No Backlight and 6X
a) Replace Power Supply
In most cases, if the Sony logo (Backlight) momentarily illuminates
and the TV shuts off and a 6X is activated than one or more of the
backlight LEDs are defective. The LCD Panel assembly panel must
be replaced for a defective LED. However, before replacing the LCD
panel assembly check for a complete loss of the Negative Backlight
(-89V to -125V) power supply. The -89V to -125V power supply can
be checked at CN6702/pins 1 & 3.
Defective Panel LED(s)
Defective Power Supply
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