Huawei Matebook D15 DAH95AMB8C0 - niski opór na linii 5V

Mam problem z płytą do Huawei-a. Poszło jakieś przepięcie/wyładowanie wypaliło jedno zabezpieczenie ESD, pare rezystorów i kondensatorów w okolicy gniazda słuchawkowego plus zwarło układ karty dźwiękowej i KBC.
Na początku było duże zwarcie i grzał się układ karty dźwiękowej i KBC. Obydwa układy wymienione (oczywiście KBC zaprogramowany wsadem wyciągniętym z oryginalnego bios-u.) po tym zabiegu opór na linii 5V podniósł się tylko do 250Ω i wróciły napięcia 1V, 3,3V, 5V. Aktualnie nic się nie grzeje. Płyta nie reaguje na przycisk power.

Jak podam napięcie na linię 5V to pobór jest rzędu 70mA. Płyta na zasilaczu pobiera 20mA
Wpadła w moje ręce druga sprawna płyta i porównałem opory poza tą linią 5V, która w sprawnej ma kΩ pozostałe są bardzo zbliżone.

Poniżej zdjęcie tego co namierzyłem, że łączy się z linią 5V i próbowałem wylutować. Wylutowanie tych układów nie podniosło oporności linii.

Może ma ktoś jakiś pomysł jak dalej ugryźć ten temat.

Obawiam się, że razem z kodekiem audio i kontrolerem KBC "strzelił" most PCH w hybrydzie. Podłącz napięcie w linię 5V i sprawdź po godzinie (gdy linia pobiera te 70mA), czy mniejszy rdzeń hybrydy nie zaczął się robić ciepły - jeśli tak, procesor do wymiany.

Zostawiłem na kilka godzin linię 5V podłączoną most jest zupełnie zimny. Minimalnie ciepły jest TPS ale on nie jest uszkodzony bo już go odlutowałem opór bez zmiany. Wymieniłem na nowy również żadnej zmiany nie zaobserwowałem.

Jeszcze podejrzewam KBC tego co kupiłem, że nie do końca jest sprawny. Kupiłem drugi od sprawdzonego sprzedawcy i czekam.

The 5V switching coil should be removed from the board during the short circuit test at 5V power supply rail.
Repeat the test with removed 5V coil. What is the electrical current consumption at 5V in this case?

Also measure the resistances to ground on data lines and on power supply pin of all USB ports. Note that each USB 3.0 port has a three pairs of data lines (6 pins).

At the beginning thank you for response. Yes I know that I should remove coil and I did it. I injected power without coil. But still TPS get a little bit hot.
The amount of heat TPS produced you feel only with your cheek .
This 250Ω is on a line site. Whereas on TPS site there is resistance in kΩ.
I attached photo with all measurements on usb ports.

It seems the TPS chip on this board has an additional line connected directly to 5V output line for a "charge pump" power supply or output voltage monitoring.
Which TPS chip exactly is on this board?

Remove the TPS chip from the board and remeasure the resistance to ground on 5V power rail. What is an electrical current consumption at 5V line without the TPS chip?

The resistances on both USB ports seems fine. Check, if there is an additional USB port(s) on small board if it is present. If so, also measure the resistances to ground on these USB ports (the small USB board should be connected to the motherboard during the measurement).

TPS650832.
When I removed TPS I checked resistance and it was the same. I don't remember exactly how much of current it takes without TPS but a a little bit less. I will check it once again but after I replace KBC. I hate to remove TPS because of reballing, without stencil I need good amount of time to put balls on this IC.

There is one more usb port on separate board but I don't have this little board now. In a mean time I checked resistance on connector which connect this little board with main board and it is KΩ, MΩ or GND nothing what could raise my suspicious.

elenium115 napisał(a):I hate to remove TPS because of reballing, without stencil I need good amount of time to put balls on this IC.

If you have an universal stencil with 0,5mm pitch and 0,3mm (or 0,35mm) holes you can use it.

Here is an example how I used a stencil with 0,8mm pitch. Your is a bit smaller, but anyway. I covered the excess holes with a kapton tape.

I will back to the subject. I replaced IT8987E and program it. Now board react on power button and I have boot loop. 41 blue flash and reboot. Anybody know where now the problem could be?

https://www.youtube.com/watch?v=xV9f1snVG_s&ab_channel=elenium115

Have you checked the machine with a suitable USB Type-C power supply? Not all machines work with such adapter cables.

This machine doesn't have usb-c at all. There is only two wires power connector. This is the third machine I've been work on. All previous works perfectly on my laboratory power supply.

- Measure the voltages to ground on all coils, when the machine is turned on (LED flashes).
- Measure the power consumption (in mA) of the board before (machine turned off) and after (LED flashes) pressing to the power button.

Power consumption before 15 mA after 162mA

Remeasure the resistances to ground on all coils.

The resistance to ground on 5V coil is still too low. Without the schematic it is hard to find the reason for low resistance.

Post a pictures of all the chips on the board with visible markings.

https://youtu.be/6AfevKm-HDM - video










I finally get somewhere. The reason for low resistance on 5v rail was Intersil IC. I started to remove ICs one by one and found this one.
Now I don't have boot loop but board still not working. I get contant flashing blue light. Voltage and resistance below. Any idea?



I attached schematic which is a little similar to my board.

elenium115 napisał(a):The reason for low resistance on 5v rail was Intersil IC

Have you replaced that chip with a functional one?
If so, remeasure the power consumption (in mA) of the board before and after pressing to the power button.

Power consumption before 4mA and after i push power button 206mA. I start to think that bridge is broken I experimented with different RAM modules and about 6 - 7 different bios-es nothing change. I know that when I press the button KBC i comunicating with bridge and start CPU than GPU. In my case CPU is not getting on. Which signal is from bridge and goes into KBC?

Birdge, GPU and of course TPS is getting little bit of heat . CPU is completly cold.

About this Intersil IC i took brand new and because somethimes even new are broken I took another one soldered it but the result is the same.

elenium115 napisał(a):Which signal is from bridge and goes into KBC?

The KBC and PCH part of the APU communicates via LPC bus. This bus consists of several data lines.

The further diagnostic is difficult without a schematic.

elenium115 napisał(a):I start to think that bridge is broken

Unfortunately it is quite likely, as @Vogelek23 has already said.