• Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

It is currently 14 December 2024, 05:32

Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

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#1 Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by tknach • 20 May 2024, 11:34
Lenovo Ideapad Flex 5 14ALC05 brak obrazu.
Platforma Wistron LC56-14A
Ryzen 5 5500U
nuvoton ncpe386pb0dx

Płyta startuje.
Brak napięcia PWR_1D2V.
Cewka PL5101 0 Ohm
PU5103 na źrodle, bramce i drenie zwarcie do masy.
Po wylutowaniu tranzystor działa poprawnie.

PU5101
na pinach 5 PWR_VDDQ_VDDQ ,16 PWR_VDDQ_PH,19 PWR_VDDQ_VLDOIN zwarcie do masy

Gdzie szukać możliwego zwarcia ?
Możliwe jest zwarcie na kościach ram ?

Re: Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by Google Adsense [BOT] • 20 May 2024, 11:34

#2 Re: Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by matic • 20 May 2024, 11:57
Hello!

Remove the coil PL5101 from the board and measure the resistances to ground on both pads on the place of this coil.

- If the short circuit to ground is present on the converter side (rail "PWR_VDDQ_PH"), the controller chip PU501 is very likely damaged.
- If the short circuit is present on the system side (power rail "PWR_1D2V"), perform a short circuit test described here (lesson #3). For a short circuit test limit the voltage to 1.2V.

tknach wrote:Możliwe jest zwarcie na kościach ram ?
In the case of a short circuit on the system side, the OnBoard RAM memory chips may be damaged, but there are also other possible causes.

#3 Re: Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by tknach • 20 May 2024, 15:23
Thank you for fast response.
I removed the coil PL5101.
The short circuit is present on the system side (power rail "PWR_1D2V").
From the converter side I have ~1.5 MOhm so no short circuit.
I'm going to perform a short circuit limit voltage test.
I let you know what's happaned.
Thank you so much.

Re: Lenovo Ideapad Flex 5 14ALC05 LC56-14A brak obrazu, brak PWR_1D2V RAM

by Google Adsense [BOT] • 20 May 2024, 15:23
 This topic is marked as ARCHIVAL. Please only reply if your message contains the solution (Terms and Conditions p. 12.1).
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