Dell N5110 (48.4IE01.021) DEAD

[orientalsniper]

Hello all, I've just received this laptop, I already reflashed BIOS, pins 1 and 8 don't have 3.3V.

So I was checking the powerup sequence in the schematics (attached) and I have the following readings in PQ4001:

Pin1: 0v
Pin2: 3.3V (PWR_CHG_ACOK)
Pin3: 19.50V
Pin4-6: 0V

Are those readings ok?

[orientalsniper]

Re: Dell N5110 (48.4IE01.021) DEAD

Update:

Readings in RT8223:
VIN: 19.50
PGOOD: 3.3V
LL1: 5V
LL2: 3.3
VREG5: 5V
VREG3: 3.3V

I'm going to be needing help on what values should I be getting from the KBC.

[orientalsniper]

Re: Dell N5110 (48.4IE01.021) DEAD

Also, what reading should I have in ACOK of battery charger (PU4001)? It's a BQ07A and not a BQ24745 according to schematic.

[orientalsniper]

Re: Dell N5110 (48.4IE01.021) DEAD

Another update:

Pins: 3, 14 and 15 of BQ07A are shorted against ground.

EDIT:
Disregard that, had adapter plugged.

[jeremykum]

Re: Dell N5110 (48.4IE01.021) DEAD

I do not know if this helps, I had experienced on many Acer that doesn't start up above 0.7A the culprit is the Intel PCH.

Also compaq that the standby LED doesn't lit up, also a failed Intel PCH.

I do remember I read somewhere that the PCH also affects the standby and a failed PCH chip can cause the board not booting at all or not booting fully.

For now, seems like you have 3.3V and 5V properly supplied. So I assumed that the power on button also has 3.3V supplied, and pulled to ground when button is depressed.

Try check Page 45 TPS51218 for 1D05V_VTT supply to PCH. Maybe some shortage that prevents that startup.

[orientalsniper]

Re: Dell N5110 (48.4IE01.021) DEAD

Sorry for lack of reply, was working on other laptops. All the pins TPS51218 are not shorted against ground.

There were 2 things that happened though:

1) PU4103 (TPS51123) was getting very hot, so I swapped it with a TPS51125.

2) The original BIOS chip was failing and I swapped it with another one. It was working for a few reboots, then it stopped working altogether and BIOS was corrupted, so I reflashed, rinse and repeat until replacement BIOS chip was failing too.

I don't know what is causing the BIOS chips to fail, any ideas?

[orientalsniper]

Re: Dell N5110 (48.4IE01.021) DEAD

I'm getting 2.4V in Pin18 (ENC) of power IC (TPS51125), that's not good right?

[Roshni16]

Re: Dell N5110 (48.4IE01.021) DEAD

I Can't able to understand the "PWR_CHG_ACOK" meaning and how much voltage available at that point in Dell Inspiron 14z - 5423 model. and how to create voltage at this point.
Charging Ic : BQ24727