HP Elitebook 2540p - WP884AW#ABU - won't start!

[smaniak]

The laptop won't start. When plug power supply, on 19V in gives me 0,14A, without turning on the laptop.
I check it with thermal camera, and there is one resistor that is very hot, I change the resistor with new on but the result is the same.
In the attachment there is schematic of the resistor area, and schematic of the laptop.
I can't understand, why this resistor is getting so hot.

[mon2]

Remove all power. Meter in resistance mode. Measure the resistance to ground on the side at ~4v4. Post the measurement.

[smaniak]

Remove all power. Meter in resistance mode. Measure the resistance to ground on the side at ~4v4. Post the measurement.

On the 4.4V side, resistance to ground is like 30,68MOhms

[mon2]

Flux and lift up one leg of diode PD22.

Power up again and check if this resistor is still getting hot.

What is the voltage to ground now on each side of this resistor?

[smaniak]

Flux and lift up one leg of diode PD22.

Power up again and check if this resistor is still getting hot.

What is the voltage to ground now on each side of this resistor?

The resistor is still getting hot, and the voltages are the same.

[smaniak]

I lifted up PD2 and PD8 and still the problem was there. Then I decided to remove TPS51125RGER and now the mesurments aroudn resistors are OK.

[mon2]

Then the earlier resistance check to ground was in error. Measure the resistance to ground again after this 100 ohm resistor and post a pic of your meter face with the measurement. This resistor will only be hot if there is a heavy load on the downstream side.

[smaniak]

This is after 100ohm resistor to ground now, without TPS51125RGER.

[smaniak]

I found TPS51123 on one of my old motherboards, and I put it instead of old one TPS51125 /that was on the board originally/. The result is the same, this resistor is still very hot.

[smaniak]

This is from the thermal camera.
The hotest one is the resistor.
The other one near to resistor is PU303 - APL5317.
And the far right is TPS51123

[smaniak]

This is motherboard shcematic.
https://www.badcaps.net/forum/troubl...-2540p-rev-1-0

[mon2]

PD22 is a diode so has a polarity. In the post with the meter, unable to confirm that this diode is properly mounted. Be sure that the band on the diode is in the proper direction.

The backside of the arrowhead = ANODE = "+' or input to the diode. Respectively, the front side of the arrowhead = CATHODE = "-". The current will flow in the direction of the arrowhead and must match the schematic.

Confirm this important detail.

[mcplslg123]

TPS51123 & 51125 are different and not interchangeable.

[smaniak]

Yes You are right!!! I returned TPS51123!
The other thing that I see was that KBC1098 was solder incorectly. So I replaced It with new one.
And now when I plug the charger, the carger switch off for short.
With another scan with thermal camera I faund that PQ205-IRFH7914 is glowing.
I replace PQ205 and now the laptop is starting. BUT the fan is spining at full speed and there is no picture.
When I plug tester on mini pci there is nothing, 00 and no other codes.
My qestion is, is KBC1098 programmabal or not?

[mcplslg123]

KBC1098-NOT programmable.