Sony X850E Series Service Manual page 23

FLOW
1-3. NO POWER DDCON/LDO
DDCONs CHECK
START
Check fuse no
F4xx or F6xx
Is fuse OK?
yes
no
Check Vcc voltage
C4xx or C6xx
Is voltage >12.0V?
yes
no
Check Enable pin
voltage
Is voltage >2.5V?
yes
Change DDCON IC
XBR-65/75X850E
Change Fuse
1) Check POWER_ON P-on ucom #pin10
(Refer No Power U-Com Failure)
2) Check G* board
3) Check IC9000 on JK* (only AC-ADP Models)
No Power U-Com Failure
or
Enable source
IC Ref Voltage supply
IC402 +5.0V_VBUS/+5V_MAIN
+3.3V_STBY
(AC-ADP only)
IC403
/+3.3V_MAIN
IC405 +1.8V_TU/+1.8V_BE
IC404 +1.0V_BE
IC409 +1.5V_FRC
IC410 +0.95V_FRC
IC604 +1.0V_M2
LDOs CHECK
START
Check Vcc voltage no
C6xx
Is voltage >3V?
yes
Check Enable pin
no
voltage
Is voltage >3V?
yes
Change LDO IC
IC Ref
IC602
IC603
IC605
IC606
IC607
TROUBLE SHOOTING
Check +3.3V_DDC_OUT
DDCON (IC403)
or
+3.3V_STBY (G* board)
No Power U-Com Failure
or
Enable source
Voltage supply
+1.05V_M2_STBY
+1.05V_M2_A_1
+1.05V_M2_ST_ET
+1.05V_M2_A_2
VCC3IO_EMMC (1.8V)
23