dell n5110 not powering on

[d3xt3r01.tk]

Hello,

First of all, thanks for the great forum.
So, recently I wanted to give my old laptop to my parents when suddenly, as luck has it, it died. So I decided to give it a shot and fix it.
Luckly my dad has some electronics experience and started to debug this.
Found the schematic. Found out that s5 means shutdown and decided to measure PU4103 (TPS51123RGER) outputs. Input 19V is there ... No outputs. A thermal scan also showed it being the only component at 37degreesC. Went on aliexpress and ordered a 5pack.
Now, it'll take a while 'till they come and I wanted to use this time to ask you guys if there's anything else you recommend on checking ?
Just trying to validate my theory and test procedure... Keep in mind I'm a total noob ! I can do soldering and measurements so far .. but that's about it.

Thanks in advance.

[budiex]

Re: dell n5110 not powering on

Basically the measurements that are made are:
1. The adapter must have a constant current voltage without variations.
2. When connecting the adapter it must not present any voltage change.
3. Verify if the charger's recognition led lights up.
4. To verify if the button of ignition of the computer has 3.3 volts and lowers to 0 volts when pressing it, to check if it does not have continuity in its four sides.
5. The motherboard is energized with 19~20v at the power input stage.
6. On the same stage of the power input, usually there are 2 mosfets followed by a resistor that senses the voltage, these should have the same voltage or with a minimum variation as the adapter.
7. Measure the KBC if it is energized with 3.3v.
8. Check if the bios chip has voltage on pin 8.

This is the basic measurement procedure that "I" apply when a computer does not turn on.
All the voltages that I mention are only referential, these vary depending on the motherboard.
If the equipment is in S5 state, it may be the case that the bios has no voltage.

I am also new to this, but I learned this procedure well I think.

[Th3_uN1Qu3]

Re: dell n5110 not powering on

TPS chip should have 3.3v ldo output, this should also be present on some of the kbc pins and the center terminals of the battery conector. If you do have 3.3V LDO but no other outputs, flash EC BIOS, it is in a separate little eeprom.