HP 15-eh0001nf with a start issue

[alloverme]

Hello, I have an HP 15-eh0001nf with a start issue,

• First it didnt start at all power button blinking blue and no screen, but seems a boot loop*
• I tried to remove most component - > same issueI see some little corroded component, clean them with isopropyle alcool and resamble all -> it worked during less than one minute and did the same issueI
• tried to clean it again and worked few second and get same issue...
• Now dont want to start anymoreI see on thermal cam a component getting a bit hot (qr=7j 13g) and didnt find any information about it (, i tested all rail and no short..µ
  
  I feel like there is not enought voltage to boot up, how can i check that?
  
  Did somone have any clue?
  Thanks

[alloverme]

Some test of the motherboard ref dag7hamb8f0 rev f

[mon2]

If there is an '=' in the SMD marking code, immediately, the part is by Richtek.

Then search for the prefix code. So 'Richtek QR=' on Google:

https://www.richtek.com/assets/produ...S6316BC-01.pdf

Part # RT6316BGQUF should be a match. Confirm against the PCB footprint / pads.


https://www.aliexpress.com/item/1005...Cquery_from%3A

[alloverme]

If there is an '=' in the SMD marking code, immediately, the part is by Richtek.

Then search for the prefix code. So 'Richtek QR=' on Google:

https://www.richtek.com/assets/produ...S6316BC-01.pdf

Part # RT6316BGQUF should be a match. Confirm against the PCB footprint / pads.


https://www.aliexpress.com/item/1005...Cquery_from%3A

Thanks for your help, do you think this component can cause a faulty boot loop?
I find the inductor next to it 1R5 is 0.5 Ohm resistance, is it normal?

[m1ch43lzm]

Use the DAG7HAMB8E0 schematics and boardview, everything is the same with minor part differences that i found (pin compatible replacements on some parts)

https://www.badcaps.net/forum/troubl...=2#post1810731

I have 2 DAG7HAMB8F0 boards, a dead one with 4700U and a "working with some issues" one with 5700U, let me know if you want me to check something

[alloverme]

Use the DAG7HAMB8E0 schematics and boardview, everything is the same with minor part differences that i found (pin compatible replacements on some parts)

https://www.badcaps.net/forum/troubl...=2#post1810731

I have 2 DAG7HAMB8F0 boards, a dead one with 4700U and a "working with some issues" one with 5700U, let me know if you want me to check something

Thanks for the schematic, i'm a newbie in electronic repair so its har for me to read it.
Can you give me some track ?
Thks

[m1ch43lzm]

I made a picture with the voltages i measured in my "mostly working" board, it actually powers on and boots to the OS, has other issues I detailed on another thread
The boardview will help, use FlexBV Free to open it https://pldaniels.com/flexbv5/
The IC that heats up in your board is the 3.3V regulator, its an RT6316B, PU8600

With power removed, measure resistance to GND at PL8600
And also check resistance to GND at pin 11, or at PC8615

[alloverme]

I made a picture with the voltages i measured in my "mostly working" board, it actually powers on and boots to the OS, has other issues I detailed on another thread
The boardview will help, use FlexBV Free to open it https://pldaniels.com/flexbv5/
The IC that heats up in your board is the 3.3V regulator, its an RT6316B, PU8600

With power removed, measure resistance to GND at PL8600
And also check resistance to GND at pin 11, or at PC8615

Thanks a lot for your mesurement and tool !!!

GND at PL8600 -> 8.3 k Ohm

pin 11, or at PC8615 -> 33k Ohm

I found something !!!

Beacause my 1.2v rail is missing at the PL8701

The P8700 is getting out 4.5v from the 18 pin to a resistor and to a capacitor, but i lost the voltage at the pin out of the capacitor,i think its the guilty about the 1.2v rail missing!

Can you mesure the output of this cap?

Do you think i'm good?

[alloverme]

I mesure the P8707 capacitor i think the issue came from but the reading looks fine...
Why i lost the voltage at the output of the capacitor ? too low voltage input ?

I have 360 Ohm between GND and Pin 1 of PL8701, do you have the same?

[m1ch43lzm]

It's not the cap PC8707, check the schematics, one side of the cap is connected before the inductor PL8701
360 ohm at PL8701 may be ok, if you have the RAM installed
Across the inductor it's supposed to be close to 0 ohms, an inductor is a wire wrapped around an iron core.....
Is the 5V stable when the laptop is off?

The 3.3v, 1.2, 2.5 comes on after pressing the power button
You can test the board outside the chassis, the alternate power button is near the BIOS, SW5000, it's under the kapton tape in yours

[alloverme]

It's not the cap PC8707, check the schematics, one side of the cap is connected before the inductor PL8701
360 ohm at PL8701 may be ok, if you have the RAM installed
Across the inductor it's supposed to be close to 0 ohms, an inductor is a wire wrapped around an iron core.....
Is the 5V stable when the laptop is off?

The 3.3v, 1.2, 2.5 comes on after pressing the power button
You can test the board outside the chassis, the alternate power button is near the BIOS, SW5000, it's under the kapton tape in yours

The 5v rail is always Good
The 1.2v and 2.5v are never present even when power is pressed
The 3.3v is present when power is pressed

I saw the 1.2v and 3.3v are related to the PU8700 (TPS51486RJER), i saw yours getting burnt in another post, perhaps mine is faulty aswell...

Can you give the reading you get on the Pin 18 and 17 of the PU8700 ?

Thks a lot for your time

[m1ch43lzm]

PR8704 to GND - 0L in resistance
PL8701 - 729 Ohms without RAM
273 ohms with RAM inserted

PC8706 - 1M, it varies a bit

The TPS51486 generates 1.2v, 0.6v and 2.5v, it generates the voltages for RAM, the 1.2V also go to the CPU
Something in the power on sequence is failing, check MAINON and SUSON lines

I saw the 1.2v and 3.3v are related to the PU8700 (TPS51486RJER), i saw yours getting burnt in another post, perhaps mine is faulty aswell...

That's why I bought the other board with the 5700U, supposedly was tested and fully working, I haven't figured out the remaining issues with it, mostly with the fan speed and the crashing under load...

[alloverme]

PR8704 to GND - 0L in resistance
PL8701 - 729 Ohms without RAM
273 ohms with RAM inserted

PC8706 - 1M, it varies a bit

Sorry, i mean voltage when powered on?
Can you give the reading you get on the Pin 7, Pin 18 and 17 of the PU8700 ?
I add Pin 7 which is the input of PU8700, mine get 13.3V, i found there is another input of 5V in Pin 13/14

[alloverme]

I tried to find the datasheet of TPS51486RJER but the right one is impossible to find

[alloverme]

I found this datasheet which is close (or remplacement) of the TPS51486RJER https://www.ti.com/lit/ds/symlink/tp...=1752948926070
I think i understand something
The pin18 (BST) sending Voltage (by resistor and capacitor) to the pin17 (SW) to command it to get on
In my case i have the 4.5V getting out the pin18 get stuck on the output of the capacitor PC8707 and didnt go to the pin17
This can explain the TPS51486RJER didnt get the 1.2V and 2.4V out
Do you think i'm good?

[m1ch43lzm]

Sorry, i mean voltage when powered on?
Can you give the reading you get on the Pin 7, Pin 18 and 17 of the PU8700 ?
I add Pin 7 which is the input of PU8700, mine get 13.3V, i found there is another input of 5V in Pin 13/14

Pin 7 is VIN, I get 13.23V, measured elsewhere as my probes aren't fine enough, don't want to short anything
It's the voltage from the battery/main power rail, the charge circuit is NVDC in this laptop, you won't find 19v anywhere except the input of the charge circuit,so the 13V on the main rail with only the AC adapter is plugged in is correct
13-14 is the same 5V
Pin 17 is before the inductor, should be 1.2v when power on (i measured at the output)
At PR8704-PC8707 i get 4.7V with power off, may be because PU8700 is a different part
My "working" board has a G6020AMC1D (marking 6020A) chip instead, the dead board had a TPS51486

I tried to find the datasheet of TPS51486RJER but the right one is impossible to find

Datasheet not available to the public, you can look at the TPS65295 datasheet for reference
It's almost the same chip, same pinout
The G6020A installed in my "working" board has the same pinout, couldn't find a datasheet for that one either....

The pin18 (BST) sending Voltage (by resistor and capacitor) to the pin17 (SW) to command it to get on

SW is the "switching" output before the inductor, the resistor and cap are used for a bootstrap to drive the internal MOSFETs of the chip

BST, 18, High-side MOSFET gate driver bootstrap voltage input for VDDQ buck. Connect a capacitor between the
BST pin and the SW pin.

The enable signals to turn on the 1.2V, 2.5V and 0.6V are pins 10 and 11, SLP_S4 and VTT_CNTL
Check pins 10 and 11
Refer to the flow chart at page 2 of the schematics

[alloverme]

The enable signals to turn on the 1.2V, 2.5V and 0.6V are pins 10 and 11, SLP_S4 and VTT_CNTL
Check pins 10 and 11
Refer to the flow chart at page 2 of the schematics

I have 0v on pins 10 and 11 and around 30 Ohm and 90 Ohm résistance...
I look the diagram but not very understandable for me...
I saw they should be connected to the IC but didnt find the value i should get...

Pin 17 is before the inductor, should be 1.2v when power on (i measured at the output)
At PR8704-PC8707 i get 4.7V with power off, may be because PU8700 is a different part

Did you mesure at the output of the PC8707 and/or the input of PL8701?
Because if there is 4.7V at the input of the PC8707, it should still get 4.7V at the output !?

Do you have a clue of the issue?

I thinking to order a TPS51486RJER and a 0.1 Ohm resistor (PC8707)...

[m1ch43lzm]

I have 0v on pins 10 and 11 and around 30 Ohm and 90 Ohm résistance...
I look the diagram but not very understandable for me...
I saw they should be connected to the IC but didnt find the value i should get...


Did you mesure at the output of the PC8707 and/or the input of PL8701?
Because if there is 4.7V at the input of the PC8707, it should still get 4.7V at the output !?

No, that capacitor is not connected to GND, think of a capacitor as 2 plates separated by a very thin gap
A capacitor is not a wire, an inductor is a wire..., you don't get DC output after a capacitor
At the input of PL8701, it's the same 1.2V (an inductor is a wire...)
A better explanation of how a buck converter works: https://www.digikey.com/en/maker/tut...onverters-work
It's a synchronous buck converter, with 2 MOSFETs, the capacitor has nothing to do with the missing 1.2V output
The BST pin is for internal use of the TPS51486

The readings you got at pin 10 and 11 are wrong, i get 83.7Kohm at pin 10 (measured at pin 1 of PC8717, it's not present on the board but the solder pads are there), and 85.2Kohm at pin 11 (measured at pin 1 of PC8716, also not present on the board), the readings are at alternate points as i couldn't get my probes on the chip itself
PR8709 and PR8711 are just traces on the board

Something is pulling down those lines, maybe the TPS51486 or another chip is shorted

From the schematics SUSON goes to the EC IT5570, PU9600 and PU8700
MAINON goes to the EC, to PU9601 and PU8700
I don't think PU9200 is shorted, as MAINON goes through a 10k resistor to the enable pin

Do you have a clue of the issue?

I thinking to order a TPS51486RJER and a 0.1 Ohm resistor (PC8707)...

PC8707 is a capacitor, not a resistor...

[alloverme]

No, that capacitor is not connected to GND, think of a capacitor as 2 plates separated by a very thin gap
A capacitor is not a wire, an inductor is a wire..., you don't get DC output after a capacitor
At the input of PL8701, it's the same 1.2V (an inductor is a wire...)
A better explanation of how a buck converter works: https://www.digikey.com/en/maker/tut...onverters-work
It's a synchronous buck converter, with 2 MOSFETs, the capacitor has nothing to do with the missing 1.2V output
The BST pin is for internal use of the TPS51486

Thanks for your explanation, i'm a bit lost of understanding all of that sorry...

The readings you got at pin 10 and 11 are wrong, i get 83.7Kohm at pin 10 (measured at pin 1 of PC8717, it's not present on the board but the solder pads are there), and 85.2Kohm at pin 11 (measured at pin 1 of PC8716, also not present on the board), the readings are at alternate points as i couldn't get my probes on the chip itself
PR8709 and PR8711 are just traces on the board

I have remade the mesurement at the same point and i have around 91.6 KOhm at pin 10 and 96.9 KOhm at pin 11. I think i've done it previously with the power plug.
So it looks close to your mesurement...

Do you think the TPS51486 is just dead? i will order one but it will be a challenge to change it with my hot air station...

[m1ch43lzm]

It could also be anything else, also check the HWPG line, it's the "power good" connected to several ICs, the EC receives the HWPG "power good" signal

A missing voltage somewhere can cause a bootloop
Check also 1.8V and 0.75V, there's 2 0.75V supplies, +0.75V and +0.75VS5, PU9200 and PU9201, the schematics says RT8068AZQW but the chip installed in both boards I have is a G2823D, may be pin compatible

On my dead board one of those got shorted too

Attached the power diagram from the schematics, it's slightly wrong as it's missing the second 0.75VS5 supply, and the 3.3V are not enabled on power off