No Power U-Com Failure - Sony X900E Series Service Manual

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1-2. NO POWER U-COM FAILURE

START
Check VDD
no
C506 Voltage.
Is the voltage >3.0V?
yes
(only for AC-ADP model)
no
Check TYPE_DET
C503 Voltage.
Is the voltage 0V?
yes
(only for G-board model)
no
Check TYPE_DET
C503 Voltage.
Is the voltage 2.6±0.2V?
yes
Check OPWRSB
no
R443 Voltage.
Is the voltage 0V?
yes
Check POWER_ON no
R526 or P-on ucom #pin10
Is the voltage >3.0V?
yes
XBR-49/55/65/75X900E
Check +3.3V_STBY LIne (C521, CN400 #14pin)
And (only for AC-ADP model)
3.3V_DDCON (IC403)
Type Detection Circuit problem.
Check TYPE_DET Line (R521, R522, R523).
Check Power supply harness (CN400 #9pin,10pin).
Type Detection Circuit problem.
Check TYPE_DET Line (R521, R522, R523).
Check Power supply harness (CN400 #9pin,10pin).
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 or JK board).
Check 12V_MON
no
R446 Voltage.
Is the voltage >2.6V?
yes
(only for AC-ADP model)
no
Check DC_MON
R439 Voltage.
Is the voltage >1.8V?
yes
Check DC_OFF_DET
no
R448 or P-on ucom #pin3
is >3.0V?
yes
Check P_ON_#1
no
CL418 or P-on ucom #pin12
is >3.0V?
yes
Check PGOOD_1
no
R440 Voltage.
Is the voltage >3.0V?
yes
Continue next page...
TROUBLE SHOOTING
Check +12V_MAIN Line
(G board or JK board).
Check POWER_MAIN Line
(JK board).
Change IC401
Change IC401
No POWER - DDCON/LDO
Check 1.0V DDCON (IC604)
And (only for AC-ADP model)
12V DDCON (IC9000 on JK).
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