Acer Aspire 5251 (NEW75) no post

[ben7]

Will not post.

Swapped RAM, still no-go.

Checked MB and I didn't see any burn marks.

It was used, shut down, and then the next time it was turned on it didn't post.

The CPU heatsink/heatpipe (everything is connected with one heatpipe) warms up, and the fan runs, power lights light up as normal, but the screen stays dark. Checked with a flashlight and I can't see anything.

Also, the HDD doesn't spin up. A computer, when working, still should at least post even with the HDD removed, but it doesn't, it shows the same symptoms.

FYI, it's model is "NEW75"
Dunno why it is different from the name "Aspire 5251 series" ... model numbers represent different options, that would be my guess.
MB says HannStar.
NEW75 LA-5912P
MB is very clean looking, no flux residues, etc...

Also, I measured the voltage on the power adapter and it is spot on, unloaded obviously, at 19V. It's made by delta

Any ideas?

Thanks,
-Ben

[Life Goes On]

Re: Acer Aspire 5251 (NEW75) no post

Did you try with other Cpu and check cmos battery voltage.

[ben7]

Re: Acer Aspire 5251 (NEW75) no post

cmos battery voltage is at 2.81 volts. Do you think it could be the issue?
It's a soldered, presumably rechargeable, battery. Size wise, it is not as wide as a CR2032, but it is just about the same thickness. Protective plastic on it is blue.

Not sure that I have another CPU to test it with, but I will say that the CPU voltage measures 1.1V

Edit: First search result on google, for the MB part number, was for the schematic diagrams!
Checking the power rail voltages now.

Edit2: Hm, seems as though all the power rails are up and running.
Oh I forgot the schematic:

[khaahk]

Re: Acer Aspire 5251 (NEW75) no post

https://www.badcaps.net/forum/showth...ht=216-0752001
give the NB some heat and it will work. Change it with new to make a good repair.

[ben7]

Re: Acer Aspire 5251 (NEW75) no post

https://www.badcaps.net/forum/showth...ht=216-0752001
give the NB some heat and it will work. Change it with new to make a good repair.

Ahhhh hmmmm.

Well, after checking the voltages, I decided to try it with the HDD again, and it works?! Perhaps that was because it was already warmed up, if there is bad solder.
Other thing might be that the 2nd reseating of the memory did the trick... I dunno.

Will definitely put some fresh paste on the chips, will have to get some as I just have that cheap white paste...

[Life Goes On]

Re: Acer Aspire 5251 (NEW75) no post

Good pasta help a lot and also for the cmos battery i like to keep it above 3.0V, but its good to hear that it work again.

[ben7]

Re: Acer Aspire 5251 (NEW75) no post

Good pasta help a lot and also for the cmos battery i like to keep it above 3.0V, but its good to hear that it work again.

I think you meant good paste .... I'm not much of a pasta fan.

[Life Goes On]

Re: Acer Aspire 5251 (NEW75) no post

Yeah ben, you right, you got me on that.