MB Air 13 820-00165-A missing components

[Askic]

Hello guys,

I'm trying to figure out and fix the board after previous repair attempt. The board is overall very clean with almost no signs of previous work.

I noticed that U8030 IC chip is missing and that is the only area on the board where traces of work is visible.
Without this chip U8030 (TPS22924), which is 3.3V S0 switch, of course there is no PP3V3_S0 (it is 0.54V).
Without U8030, when connecting charger, fan has full speed and there is no chime, the board is "braindead".

I have performed some measurements and this is what I got:
PPBUS_G3H = 8.56V
PP3V42_G3H = 3.42V
PP5V_S0 = 5.1V
PP3V3_S5 = 3.3V
PM_SLP_S3_L = 3.3V
PM_SLP_S4_L = 3.3V

PP3V3_S0_EN = 3.23V
PP3V3_S0 = 0.54V (this is to be expected since U8030 is removed)

I'm using the schematics from here, but this is for 820-001165 and I can see that some other components that exist on schematics don't exist on the board (there are no traces that they are removed) and also same components are not present on pictures from functional boards sold on ebay.

Current I don't have a new U8030, but I wonder what was the reason it needed to be removed. Output from this chip is PP3V3_S0_FET_R and I measured this on the test pin (connected to leg nr 1 against ground on the chip) against ground in diode mode and I got 391 reading which means there is no short to ground.

It seems that the next step would be to buy new U8030 chip and to try solder it on the motherboard.

Since this chip is actually a switch, would it be advisable to try to short input and output (to bridge it) to test what happens next?

This way I would send PP3V3_S5 (3.3V) to PP3V3_S0_FET_R line.

Another idea would be to place N-channel mosfet from other DELL motherboard, glue it on the board, connect PP3V3_S0_EN to the GATE, PP3V3_S5 to the drain and PP3V3_S0_FET_R to the source.

Please let me know what you think.

[MobileXT]

Re: MB Air 13 820-00165-A missing components

That components doesn't exist on all 820-00165 board as far as I know.