Acer Aspire 4738 dark display after 2 minutes

[Th3_uN1Qu3]

Re: Acer Aspire 4738 dark display after 2 minutes

You got the units wrong: the tantalum caps you have on your board are 330uF.

[piernov]

Re: Acer Aspire 4738 dark display after 2 minutes

Those should be aluminum not tantalum btw. It's extremely rare that they fail but who knows. "Testing" them won't help anyway, or you'd need a pretty nice measurement setup to be able to measure such low ESR accurately in the first place.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,

Thank you for informing those are alum caps of 330uF.
Fyi, i think heat is the issue here. Thats why i changed a new cpu fan and added an external tabletop exhaust fan under the laptop during use. But the laptop keeps on showing windows failed to start., sometimes the blue screen.
Any idea what can i do or test now?
I sincerely need all the help and advice much appreciated.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,

Fyi, the marking on those caps are
330(first row), 08D1Y(second row)
but google can't seem to give any result.
I will desolder them to see if they are
in spec to 330uF.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,

Managed to desolder total 7pcs 330 caps
after much careful work. From the triangle cpu area and testing capacitance and esr i have the result of 365uf/0.26Ω, 252uf/17Ω and 369uf/0.04Ω.
On the lower part of the cpu, at pc22 i got 365uf/0.00Ω while at pc30 i got 378uf/0.02Ω.
On the right hand side of cpu, at c363 i got 209uf/17Ω while at c450 i got 153uf/17Ω. The way i see it is those caps showing esr more than 1Ω should be replaced. But does anyone know the voltage rating of these 330 caps? What should be the minimum voltage rating if i need to replace?
Your advice and help will be very appreciated. Thank you in advance.

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi,
I am attaching an image showing all the 330 caps desoldered on one leg for checking and their position.

[RAVI KARAN]

Re: Acer Aspire 4738 dark display after 2 minutes

Its pass the ac and block the dc supply...if it is in fix parlal mode no need to fix in circuit...

[mikey5791]

Re: Acer Aspire 4738 dark display after 2 minutes

Hi Ravi Karan,

Sorry i am unable to understand your comment.
Can you elaborate it if possible. Thanks.