Lenovo Legion 5 15IMH05H NM-C911 - brak obrazu

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DemoNx4 wrote:Sorry for the long reply time - my son was born

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DemoNx4 wrote:Brak napięcia na pin 4 z UG9.

Ponieważ masz obsadzoną bramkę UG5, zmierz napięcia do masy na pinach 1, 2, 4 i 5 tej bramki przy włączonej płycie i podłączonej matrycy. Do testów warto odłączyć dysk twardy, aby komputer nie uruchamiał się do systemu.

Dziękuję

Ogólnie walka jest o obraz na HDMI, obrazu na matrycy nie ma w nim od podobno długiego czasu i właściciel nie chce tego naprawiać, ale może ma to jakiś związek.

Pomiary są następujące dla UG5 bez podpiętego dysku z podłączoną matrycą:
pin 1: 10mV (po kilku sekundach od włączenia pojawia sie 3,3V, a następnie znika również po kilku sekundach)
pin 2: 3,3V
pin 4: 10mV (gdy na pin 1 jest 3,3V to tutaj jest 3V)
pin 5: 3,3V

Czy matryca jest podłączona do płyty przez cały czas testów? Jeśli tak, to odłącz kabel matrycy od płyty i sprawdź, czy po uruchomieniu systemu pokaże Ci się obraz na wyjściu HDMI.

Nie, matryca przez cały wątek, w trakcie wszystkich poprzednich pomiarów była odłączona.

Measure the voltages to ground on pins 1, 2 of transistor QR5821, when the machine is turned on in the following cases:
a) Internal matrix disconnected from the board.
b) Internal matrix connected to the board.
The external HDMI monitor must be disconnected from the board in all cases.

Transistor QR5821 pinout:

Internal matrix disconnected from the board:
Pin 1: 3,12V
Pin 2: 0V
Internal matrix connected to the board:
Pin 1: 3,12V
Pin 2: 0V

Measure the voltages to ground on pins 1, 5, 6, 7, 9, 29, 30, 31 of LVDS connector JEDP1, when the machine is turned on with the internal matrix connected, external HDMI disconnected from the board.

Below results:
Pin 1: 19V
Pin 5: 13mV
Pin 6, 7, 9, 29, 30, 31: 0V

Set your multimeter to the diode test mode and measure the voltage drops to ground on pins 5, 6, 7, 9, 28, 29, 30, 31, 34, 35, 38, 39, 42, 43 of LVDS connector JEDP1 with the matrix disconnected from the board.

Thank you again for support
Below results:
Pin 5: 0,485V
Pin 6: 0,853V
Pin 7: 0,530V
Pin 9: 0,590V
Pin 28/29/30: Over limit
Pin 31: 0,914V
Pin 34: 0,740V
Pin 35: 0,682V
Pin 38: 0,487V
Pin 39: 0,490V
Pin 42: 0,575V
Pin 43: 0,518V

Do you have any suggestion what can be defect? I must tell something to notebook's owner.

Test the machine with another matrix.
If it doesn't change anything, check the LVDS cable.

I don't have other matrix and notebook's owner don't want fix that issue. Important is only issue with no video on external monitor.

Measure the voltage to ground on pin 123 of KBC chip with the internal matrix connected.

Result on pin 123 is 3,24V.

The external video output may not be active until the internal matrix is detected by the motherboard.
Current measurements indicates that the internal matrix is not detected and that's why I suggested you to check the matrix/LVDS cable.

Sure, then we are in blind alley, because internal matrix didn' work from long time and notebook was used like deskop on external video ouput. If owner don't want fix that (and I don't have internal matrix for swap - too expensive only for try) then better if I return notebook. I belived it will be some logic problem with VCCGFXCORE on PL3102.

DemoNx4 wrote:internal matrix didn' work from long time and notebook was used like deskop on external video ouput.

Maybe the matrix was partially damaged initially and it was detected even though there was no picture. This time it may died completely.
If you have an option, test the matrix on another machine.

DemoNx4 wrote:I belived it will be some logic problem with VCCGFXCORE on PL3102.

I don't think so as this voltage is usually not present when the Nvidia graphics are active as in this case it currently is (at least it seems so).

- Check if the quartz YV1 oscillates.
- Check if there are any data pulses on pins 2, 5, 6 of VBIOS chip UV10, when you turn on the machine.

In notebook was matrix NV156FHM-NY4 which is expensive (only new are available), but I found probably spare NE156FHM-NX2 with lower class. I just ordered that one, should be on wednesday.

DemoNx4 wrote:In notebook was matrix NV156FHM-NY4 which is expensive

You can use any 40-pin FHD (1920 x 1080) resolution matrix.
There are many compatible matrix available.