Acer Nitro 5 LA-F951P Rev 1 Non Accende

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#1 Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 5 April 2025, 16:51

Ciao ragazzi ho questa scheda madre che non accende, aveva un corto sulla scheda madre, ho sostituito il chip PU402, ho fatto un piccolo passo in avanti, manca la tensione +1.2V_VDDQ coil PL502, se tolgo il ponte PJ501 la tensione +1.2V_VDDQ risulta presente, ho sostituito CPU e PU501 ma la tensione +1.2V_VDDQ non appare e il pc non accende.

MISURE:
PL502 - 260 Ohm - tensione 0.282 Mv, se tolgo il ponte PJ501 tensione 1.2 v.

se collego un cavo sul coil PL502 e inietto tensione 1.2 . con alimentatore da banco il pc accende e funziona regolarmente, apprezzo qualsiasi aiuto.

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Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by Google Adsense [BOT] • 5 April 2025, 16:51

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#2 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by matic • 7 April 2025, 08:55

Hello!

Measure the voltages to ground on pins 4, 5, 7, 8, 9, 11, 12, 18, 20 of chip PU501, when the machine is turned on with the jumper PJ501 closed.

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#3 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 7 April 2025, 11:05

PIN 4: 446 KOHM
PIN 5: 1.009 KOHM
PIN 7: 3.29 KOHM
PIN 8: 1.425 MOHM
PIN 9: 6.84 MOHM
PIN 11: LOL
PIN 12: LOL
PIN 18: LOL
PIN 20: 6.0 KOHM
PONTE PJ501: 114.06 KOHM

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#4 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by Machine • 7 April 2025, 14:43

You were asked for voltages not resistances on PU501.

If you are satisfied with my help, look here:
integracja-funkcji-pomogl-z-zamykaniem-tematu-i-oznaczaniem-go-jako-rozwiazany-t11083.html
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#5 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 7 April 2025, 17:03

Si vero scusate ho letto male, ecco le tensioni:

PIN 4: 0.066 MVOLT
PIN 5: 0.128 MVOLT
PIN 7: 3.28 VOLT
PIN 8: 3.37 VOLT
PIN 9: 2.14 VOLT
PIN 11: 5.14 VOLT
PIN 12: 5.0 VOLT
PIN 18: 4.66 VOLT
PIN 20: 0.067 MVOLT
PONTE PJ501: 0.126 MVOLT

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#6 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by Machine • 7 April 2025, 17:50

From the measurements it seems that PU501 is defective. Try replacing it.

If you are satisfied with my help, look here:
integracja-funkcji-pomogl-z-zamykaniem-tematu-i-oznaczaniem-go-jako-rozwiazany-t11083.html
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#7 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 7 April 2025, 18:57

sostituito due volte senza risolvere il problema.

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#8 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by matic • 7 April 2025, 21:25

Please, post a clear picture of the chip PU501 area of the board with a nearby surroundings.
Also post a picture of the same area from another side of the board.

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#9 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 8 April 2025, 06:53

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#10 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by matic • 9 April 2025, 07:51

Try to solder the RC snubber circuit.
PR504= Resistor 4.7Ω/5%, package 1206
PC518= Capacitor 680pF/50V, package 0402

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#11 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 9 April 2025, 11:35

non funziona, ho tutte le tensioni presenti tranne +1.2V_VDDQ e CPU, appena tolgo il ponte PJ501 la tensione +1.2V_VDDQ è presente.

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#12 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by matic • 9 April 2025, 12:02

Try to replace the chip PU501 with APW8868C.

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#13 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 9 April 2025, 13:26

già sostituito due volte con il modello APW8868C, ma non funziona.

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#14 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by matic • 9 April 2025, 17:41

But according to the pictures from post #9, you have soldered some Richtek chip (probably RT8207).

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#15 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 9 April 2025, 18:23

si avevo saldato due volte il chip APW8868C, poi siccome non funzionava ho provato il chip Richtek che risulta sullo schema elettrico, ma il risultato è lo stesso, sia con il chip APW8868C e il chip Richtek non ho tensione +1.2V_VDDQ con ponte PJ501 chiuso.

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#16 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by matic • 10 April 2025, 07:51

Try to load the "+1.2VP" rail with a power resistor of 0.5 - 1Ω with the jumper PJ501 opened.

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#17 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 10 April 2025, 18:12

con il jumper PJ501 aperto ho sempre tensione 1.2 presente, di preciso cosa dovrei provare?

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#18 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by matic • 11 April 2025, 09:11

We are interested in how this power rail behaves under load. Do as said - solder the load resistor and check the voltage on this power rail with the jumper PJ501 opened.

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#19 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by leonemax81 • 11 April 2025, 10:08

OK, in che posizione devo saldare la resistenza?.

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#20 Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by matic • 11 April 2025, 11:16

One pin of the resistor to the power rail "+1.2VP" and another pin to ground.
By the way, you must use a power resistor with a rated power of at least 1W.

Such a basic things with your "Service level= 3" :wtf:

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Re: Acer Nitro 5 LA-F951P Rev 1 Non Accende

by Google Adsense [BOT] • 11 April 2025, 11:16

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