Remove liquid inside laptop cpu socket S1 AMD

[whaldsz]

Re: Remove liquid inside laptop cpu socket S1 AMD

Why don't you disconnect PL12 and check again, if it will pull down the 19v B+ rail to 2V.

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

A small update. I found that when I insert CPU PQ35 and PQ36 are getting very hot, like 70C. Also coil PL13 is getting very hot (page 38)! I did a search and noticed that PC105 capacitor is completely missing! Thought that it was normal not to be a capacitor there as a lot of components on motherboards are not necessary and missing like on other mobos.

Take a look it looks corroded but I really don't know where the capacitor went!! It wasn't inside case anywhere I think...

So could this cap be the reason of short circuit I am having on CPU power feed or it is irrelevant and should be working anyway? What do you think?



SHOULD BE LIKE THIS:

[momaka]

Re: Remove liquid inside laptop cpu socket S1 AMD

That cap is not a cause for the short circuit. However, you definitely DO need it there, otherwise there is nothing to absorb the energy from the coil in the buck circuit. This can lead to big voltage spikes, which can sometimes kill whatever is attached to that line. Add the cap in and check again. If your MOSFETs and coil still overheat, it's probably too late, and whatever that line powers may be now dead.

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

Yes I was afraid of that cause I know that a capacitor acts mainly as a filter. This circuit is feeding power to the ATI chipset/GPU... Oh well I will change it with a new one and see from there! Will keep you updated! Thanks again momaka for replying!

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

A small update: I installed PC105 capacitor and removed completely Coil PL13 (page 38) and now LED power on has appeared with CPU inserted. So I found the short and it is on the side of power CPU and northbridge. Motherboard cannot start of course because I have removed coil and no power goes to NB and CPU.

What do you think?

[Tea_4_2]

Re: Remove liquid inside laptop cpu socket S1 AMD

In the past i did wash some boards in my dishwasher machine with success and then dried them in the oven at a temperature around (and alittle above) 100 degrees celsius i did also pre spayed them with a mild cleaner no clorine nor amonia to spray the board with air is also a good idea before et it dry completely.

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

Here is a diagram of the shorted path: Maybe CPU or Northbridge is busted/burnt?

[momaka]

Re: Remove liquid inside laptop cpu socket S1 AMD

Often times, it is normal for a large BGA chip such as the NB, GPU, and CPU to read as "shorted".
How many Ohms is the NB showing when you try to measure it with the multimeter (and what is the lowest your multimter can measure when you short its leads)?

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

The lowest when shorted the leads is 0.2 Ohms and when I touch the probe to PC105 is 0.3 Ohms with and without CPU inserted. Also PC105 cap is new because it was completely blown from the short I am guessing when spillage occurred. +VDDNBP goes to CPU and Northbridge power section.

It is a very rare motherboard so it is not easy to replace. Only in India have seminars and classes about Laptop Chip Level Repair. I wish it could be closer to where I am living...!!
Thanks for replying!

[momaka]

Re: Remove liquid inside laptop cpu socket S1 AMD

If you can obtain a NB from another dead board, you may try replacing yours. Or alternatively, if you are comfortable with lifting/reballing/reflowing, remove your NB and see if short disappears. Slight chance there may be a shorted ceramic capacitor instead of the NB being shorted. If you have a low-voltage, high current power supply, you can apply that to the NB +VDDNBP line and see if any of the ceramic caps around it get hot. However, if you do that, make sure your NB has a neatsink on it (if it had one in the first place) and also ramp the current from the power supply slowly rather than cranking it on high from the start. You will need to check a spec sheet or schematic for the laptop as well to see what the +VDDNBP is supposed to be - you definitely don't want to go higher in voltage. Lower is okay and a good idea.

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

Thank you for well written instructions! I am building an electronic lab in my basement because of lack of space. I am definitely planning to buy a bench lab Power Supply to be able to find shorts with variable voltages. One question. How will I pass the voltage to where I want eg at a pin of a Mosfet or at a resistor? Could I solder it? Most power supplies are using crocodile clips, correct?

[momaka]

Re: Remove liquid inside laptop cpu socket S1 AMD

Yes, you can solder a piece of wire and attach the crocodile clip (we call it aligator clip, but it's the same thing ) to that. I have a small box of short scrap wires (mostly 26 to 18 AWG) I use for that and other similar purposes like testing voltages on a small IC but not wanting to risk shorting the pins with my multimeter leads.

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

Oh I see! Can you link to a picture or eBay just to have a visual?

[momaka]

Re: Remove liquid inside laptop cpu socket S1 AMD

This what you mean?
http://en.wikipedia.org/wiki/Crocodile_clip

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

no about the wire. It is insulated, right?

[atsio]

Re: Remove liquid inside laptop cpu socket S1 AMD

The lowest when shorted the leads is 0.2 Ohms and when I touch the probe to PC105 is 0.3 Ohms with and without CPU inserted. Also PC105 cap is new because it was completely blown from the short I am guessing when spillage occurred. +VDDNBP goes to CPU and Northbridge power section.

+VDDNB is only NB power (not CPU). Remove and check C42 C43 and C49 decoupling capacitors. Also check resistance on all coils of power regulators to see if there is a short elsewhere that causing NB to short (that is, without CPU inserted to slot)

Yes, you can solder a piece of wire and attach the crocodile clip (we call it aligator clip, but it's the same thing ) to that. I have a small box of short scrap wires (mostly 26 to 18 AWG) I use for that and other similar purposes like testing voltages on a small IC but not wanting to risk shorting the pins with my multimeter leads.

The best and fastest way to test smt's, is by replacing the probes on DMM with needles.

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

Can't find C42 C43 and C49 cause there is no numbering on most capacitors at PCB as you can see from the pictures which is very frustrating. I can take a detailed picture of southbridge section if you want!

You have to hold needles with both hands to power up the specific section and the how will you use multimeter? Excuse my noob questions!!

[atsio]

Re: Remove liquid inside laptop cpu socket S1 AMD

Can't find C42 C43 and C49 cause there is no numbering on most capacitors at PCB as you can see from the pictures which is very frustrating. I can take a detailed picture of southbridge section if you want!

There should be near K16, M6, P16, T16, V16 of NB (probably the other side). You can find them by checking which capacitors are shorted.

You have to hold needles with both hands to power up the specific section and the how will you use multimeter? Excuse my noob questions!!

I was just referring on testing smt's with DMM without worrying of causing a short.
Of course and you need cables to supply voltage to smt's in order to activate them or check for shorts (heat) and you have to use good quality one's because the current maybe high.

[momaka]

Re: Remove liquid inside laptop cpu socket S1 AMD

no about the wire. It is insulated, right?

Oh, I don't know what's in that box. It's whatever leftovers I've collected over the years from various projects. Some is insulated, some not, some is stranded, some solid-core... long pieces, short piece... it's a wire "junk box" really .

The best and fastest way to test smt's, is by replacing the probes on DMM with needles.

That, or you can buy a set of fine probes. There are cheap ones on eBay (though their quality is hardly any good... but they do okay if you are carefull with them).
Also, sometimes I need to make measurements over a long period of time. In such cases, holding the multimter with my hands all the time is not practical. That's where I solder in wires and use jumper leads to connect my multimeter probes.

[Dimitrios]

Re: Remove liquid inside laptop cpu socket S1 AMD

Removed northbridge/gpu ATI 216-0752001 RS880 but short remains on +VDDNBP rail. Can anyone confirm that +VDDNBP power rail is the same with +VDDNB on page 38 of schematics that uploaded earlier??

I think that the shorted capacitor must be on page 8, bottom left, one of C42, C43 or C49 but cannot locate those cause there is no numbering on the board for most of the capacitors...
Will try what Atsio mentioned in earlier post.