Sony KD-49X7 D Series Service Manual page 20

1.2 No Power u-com Failure
START
Check VDD
no
C419 Voltage.
Is the voltage >3.0V?
yes
Check DC_OFF_DET
no
C504 Voltage.
Is the voltage >3.0V?
yes
Check OPWRSB
no
R441 Voltage.
Is the voltage 0V?
yes
Check POWER_ON
no
P-on ucom #pin19
Is the voltage >3.0V?
yes
Check P_ON_LNB
no
P-on ucom #pin15
Is the voltage >3.0V?
yes
BFM Board Model
Check +3.3V_STBY
C413, CN400 #24pin
Check DC_OFF_DET
IC400
SOC
Muffin 2
problem
Try AC Off and On after few minutes.
If #pin19 keep Low, change IC401.
If #pin19 goes High few seconds and downs to Low,
Check +12V_MAIN Line (G board, LD or IC409).
Change IC401
Check MAIN_VCC
no
R437 Voltage.
Is the voltage >1.6V?
yes
Check P_ON_VBUS
no
P-on ucom #pin11
is >3.0V?
yes
Check P_ON_#1
no
P-on ucom #pin13
is >3.0V?
yes
Check PGOOD_1
no
R434 Voltage.
Is the voltage >3.0V?
Continue next page...
20
Check +12V_MAIN Line
(G board, LD or IC409).
Change IC401
Change IC401
1.3 No POWER - DDCON/LDO
Check 1.0V DDCON (IC604)
And (if it is mounted)
12V DDCON (IC409).
20