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1-2. NO POWER U-COM FAILURE
START
no
Check VDD
C419
Voltage.
Is the voltage >3.0V?
yes
no
Check DC_OFF_DET
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
no
Check P_ON_LNB
P-on ucom #pin15
Is the voltage >3.0V?
yes
XBR-49X835D
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
TV Business Division
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
no
Check P_ON_#1
P-on ucom #pin13
is >3.0V?
yes
no
Check PGOOD_1
R434
Voltage.
Is the voltage >3.0V?
Continue next page...
TROUBLE SHOOTING
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).
22
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