ASUS M50VM\X57Vn IT8512E Filter? Caps

[wheezardth]

Hello everybody at Badcaps.net!

I have quite a specific problem with my Asus X57Vn (M50VM) notebook. After a bog-standart shutdown, my notebook never wanted to completely POST. It starts, and after a couple of seconds it just powers down. AC indicator does not light up no matter if the cable is plugged in or not, and battery does not seem to charge.

After taking the laptop apart, suspecting the barrel jack connector to have desoldered (it had not), i found two leaked SMD caps near the ITE IT8512E system management chip. That explains why it can't properly power up. Judjing from the ammount of goo they sprayed all around, i reckon it was a thermal stress failure.


Please, I need help in identifying those two caps so I can replace them and restore proper functioning to the system management IC. I really don't know where to get started here.



Best Regards,
-S

[Toasty]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

Those caps don't leak. Ceramic type. Looks more like something leaked onto them. Soda or other beverage? Battery?

At first, try cleaning the area with a small amount of water and Q-tips and/or and old toothbrush. See if it softens it up. If not then try some isopropyl alcohol; 70% or higher.

Toast

[wheezardth]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

Honestly, i was quite curious to see SMD caps in such a dire state. I cleaned them up with some isopropyl and i really can't fathom what could make such goo mark, exactly around those two caps. It had a glue-like consistence after it got dissolved. I'll try to POST today, after i put everything back together, but the caps still seem damaged.

Thanks fot the feedback Toasty! Any suggestions for further testing?

[Toasty]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

>>but the caps still seem damaged.<<

In what way?

Can you post a "cleaned up" pic?

[wheezardth]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

Well when i was poking around with the Q-tip and isopropyl, i noticed that the smaller cap is loose (the one with the "horn") and it came off the solder pad with a gentle nudge, thankfully leaving behind the shiny copper solder pad intact. I touched the other, bigger cap with my soldering iron, and added a drop of solder to reinforce the contacts. It did give of a faint nasty smell, but I'll try to resolder the tiny cap and boot.
Toasty, what if the caps are tantalum? Can they fail like this?

[wheezardth]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

I wasn't able to solder the black cap back =/ One side tins perfectly the other doesn't want to catch at all - any tips?

[Toasty]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

Try scraping -gently- on the end with a sharp blade. It is likely oxidized from whatever that compound was you removed. You just want to exposed the tinning to be shiny. Be careful.

Tantalum caps are usually larger than those. Without any markings, there is very little chance of identifying them anyway. Even if they were tantalum, the amount of "leakage" that was on the board, is not consistent with the size of those caps.

Toast

[wheezardth]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

Thanks Toasty. I tried scraping the edge of the cap, i got it shiny and it still doesn't want to tin - amazing! I'm starting to think that the metal laminate fell off. Any tinning tips or something else?

[Toasty]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

Yes. If the edging and end are black as the body is, then you've lost the laminate. Whatever that liquid was it seems like it was corrosive.

No silver showing at all, correct?

Try an ohmmeter from the good end to the bad and see if you get any reading. Perhaps it is a resistor...? If not, I'm afraid your SOL on this.

Try putting it back together and see if there is any change.

Going back to the original post, have you tried a different power brick? Have you measured the brick's outputs? With no AC/Charge indicator, it's a more likely place to start. Then move onto where it connects to the laptop and the surrounding circuitry.

Does it run on just the AC adapter with no battery installed?

Toast

[wheezardth]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

Hi Toast,

I tried on another power brick - no luck.
It powers on for a second, displays boot stuff and then powers down. Same on battery. When i plug in the AC, i don't get the usual LED to light up - obviously something is wrong with the power management IC. I traced the paths to the IC - the big cap lands onto what seems to be pin2 on the package, other end connected to common ground. The smaller cap is connected to a thick trace, running nearby, wich makes a short "bip" when i measure it to ground. This gets me thinking that this is a decoupling cap to a line from the PSU/voltage regulator subassembly. I'm trying to get a datasheet for that IC - maybe i can find out more. I also have some other ideas, regarding adjecent identical components - they were most probably laid down by the same pick-and-place machine in the same batch - high chance they will be identical. Manufacturers try to reduce the different types of components in manufacture, and a bypass cap is most probably standart along the several assemblies.

Also, now i am pretty confident that the failure was caused by something external, maybe caulking, and not the caps themselves - there is hardly anything that can leak from that ceramic chunk =)

[Toasty]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

"After a bog-standart shutdown,"

What does that mean?

The power management IC could be sensing an overload and stopping power-up. Just with power brick connected, are you saying that you don't even get a charge indicator LED?

[wheezardth]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

I'm not totally sure if i shutdown properly because I fell asleep that day. Could have been an "abnormal" shutdown.

But in any case, one capacitor has desoldered and delaminated, so i assume it was thermal stress.

With just the power brick connected, i still don't get a charge indicator LED, but doesn't seem to stop me from booting briefly.

[wheezardth]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

By the way Toasty, thanks for the tons of support.

[wheezardth]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

I think i got it! I followed the traces with my multimeter and found that after going through one more tiny cap on the other side of the board, this cap connects to ground - so there is a high chance that this is a decoupling/coupling cap to ground the IC.

If the ic can't get proper reading about ground condition, it would make sense that it refuses to continue working after initialising.

[wheezardth]

Re: ASUS M50VM\X57Vn IT8512E Filter? Caps

Turns out the tiny black thing is 0ohm resistor - i found many of those populated throughout the MB PCB. I resoldered one from the card reader (non-critical for me) and tried to boot with no avail.

As there was still goop around the whole thing, i will desolder and examine the larger cap beside it. Hopefully i will find the failure there