820-00840 wont power on

Kyle93

Active member
820-00840 arrived with water damage on backlight circuit and U7650. Rest of board was spotless. Replaced U7650 and two capacitors that were affected by the spill but board still does not power on. U3200 and U3100 were spotless but still reflowed them to rule out. PPDCIN only 0.35V on pin 2 of R7020 but R9920 is 5.20v
 

Kyle93

Active member
3V3_G3H .347 F7000 .358 R7020 .360

Replaced both CD3215 from donar but no change. Yes, matched it with other C00
 

2informaticos

Administrator
Staff member
That means you have 3V3_G3H.
That requires at least 5V at R7020.
Did it appear after changed the CD3215 chips?
Any other signal change?
 

2informaticos

Administrator
Staff member
There is something strange.
As per schematic, 3V3_G3H power supply gets input voltage BEHIND R7020.
Also U7000 enables 3V3_G3H...
 

2informaticos

Administrator
Staff member
"PM_EN_P3V3_G3H 5V"
Are you sure?
Should be 3V.

"Post some voltages for U7000 chip."
VDDA/P, AUX_DET, AUX_OK?
 

Kyle93

Active member
When replacing cd3215s I used 0.30mm solder balls instead of 0.25 from donar. Could that alone cause a issue? Have new ones on the way.

Yes PM_EN_P3V3_G3H measures 5.10V on R6991. Checked again.

VDDA/P 5.10V

AUX_DET 1.294V

AUX_OK 3.4V
 

2informaticos

Administrator
Staff member
"AUX_DET 1.294V"
So you have 5V at R7020!!!

"VDDA/P 5.10V"
This is also impossible without that voltage.

Please be sure to make good contact when you measure something on the board.

Also be sure CD3215 chips are properly soldered.
 

Kyle93

Active member
Both CD3215s have been replaced with new ones and still stuck at 5.20V

PP3V3_G3H 3.3V

Can anything cause it to be stuck at 5.20V??
 
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