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820-00850 Has 5V cycling down to 0V on right side only

bjf

bjf

Member
This board had very minor liquid-damage. The side that didn't have any visible liquid-damage is cycling every 5 seconds from 5V on F3000 and F3001. The other side stays steady at 5V. PPBUS is at 12.3V. LDO voltage is coming up to 3.4V and PP3V3_G3H is also coming up to 3.4V. I haven't been able to find any shorts. Not sure how these 4 ports are divided where one side is having an issue the other side isn't.
 
2informaticos

2informaticos

Administrator
Staff member
Which schematic do you use for repair?
Compare diode on power lines of all CD3215 chips.
Does the board start with 12.3V at PPBUS_G3H?
It should have 13V there?
Seems like bad communication between SMC and ISL9239.
Do you get correct SMC_RESET_L and CHGR_ACOK?
 
bjf

bjf

Member
As different as this board is from the older ones, the CD3215 areas are laid-out almost identically so I think the 820-00239 is pretty accurate there. Diode measurements are all the same at around .180. Slightly higher than the older boards.
I'm guessing PPBUS should be 13V and yes, this is an SMC-related issue. Board is not turning on with either side plugged in. I don't see CHGR_ACOK in the 00239 schematic and I still can't find SMC_RESET_L. There's nothing that's standing out yet. The SMC area is very different. Those SMC_RESET_L pads are gone.
 
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2informaticos

2informaticos

Administrator
Staff member
I was looking 00840 schematic first; didn't know which one used you.
SMC_RESET_L is there too (R7090).
SMC_AUX_OK is same as CHGR_ACOK...
 
bjf

bjf

Member
R7090 is either gone or has been moved to a place that's not very obvious. I can't find it. I went off of what looks like R8592. SMC_AUX_OK is also nearly impossible for me to locate. That whole area around R5187 is completely different.
 
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