Laptop

[pcdee]

Hello all

This is my first thread so be gentle........lol

Right, my problem is with my laptop. I suspect bad caps, I have done continuity tests on them and most failed. Is this type of test okay? Basically if the cap is shorting I will get a current pass through.

The picture is one that I have taken from this forum but I have circled what I need to know, are these are caps? As when I do the continuity test it fails is ment to let current through?

[Per Hansson]

Re: Laptop

That is correct, continuity should fail otherwise you have a connection between positive and ground which will obviously lead to a shortcircuit...

The caps you show above rarley fail... (still it does happen)
It is usually pretty obvious if they indeed have failed though, being visually thicker on the sides or blown top or bottom with allot of electrolyte all over the place...

[willawake]

Re: Laptop

it would not be common for most of the caps to fail continuity test. you may be doing the test incorrectly.

in a bad case i would expect for only 1 or maybe 2 of the caps to be shorted. It would be better to use a low ohms meter to test the ESR of the caps really.

regarding whether the test is ok, it is not recommended to pass voltage through the cap which exceeds its rating. and certainly you should not be passing voltage through the circuit in excess of the maximum expected at those points. i have no idea what you are using to test but if it has voltage then you should be careful especially because you are indicating caps for vcore in the pic.

give us more info about the issues with the laptop that you are experiencing and also the brand/model. Perhaps a photo also, since you have the board out. There is also possibility that the problem is not the caps and we should examine that as well.

[Rainbow]

Re: Laptop

A shorted cap will usually find itself - it will blow up after turning the power on.

[pcdee]

Re: Laptop

Thanks for the replys

The laptop brand is Fujitsu and motherboard is 258KAO. I have taken a photo of the m/b and circled the problem caps.

The metal ones all fail the continuity test which seems odd, maybe it's not. And it looks like the two yellow caps have failed too.


I'm doing the continuity test on a multimeter set on 200ohms. I think this is a safe setting, do correct me if I'm wrong.

Please click on the Motherboard link
I forgot to add the cap near the battery it's a Teapo 220uf 25v

[Rainbow]

Re: Laptop

I don't think you have a problem with the caps.
Testing caps in-circuit with an ohm-meter does not give you any useful result as there are other things connected parallel to them (such as CPU or chipset).

[pcdee]

Re: Laptop

I'm a bit stuck then, any idea's?

[Rainbow]

Re: Laptop

What's wrong with that laptop?

[willawake]

Re: Laptop

you indicated almost all of the good caps on the board. all the major caps are polymer caps except for the 2 teapos. i would only really worry about the teapo caps but they are quite small values.

my friend has similar fujitsu athlon64, it started shutting down under heavy 3d. i didnt hear back the solution yet, i thought it might be dust in the fans.

[pcdee]

Re: Laptop

The laptop turns on, only the fans run and you just get the black screen.

I have tried connecting it to my monitor but no joy, I have bought a brand new psu and still no joy.

[Rainbow]

Re: Laptop

What happened when it stopped to work?

[linuxguru]

Re: Laptop

Laptops fail for a lot of reasons unrelated to caps.The caps probably aren't the cause of failure here.

From the pic, I can see that there's too much thermal goop on the CPU - Arctic silver or whatever. Carefully clean it out and re-apply a smaller quantity on the die *alone*. Reseat the CPU. Reseat the DIMMs. Did you attempt a CPU upgrade and does the BIOS support this CPU ?

[pcdee]

Re: Laptop

The caps do look okay I must say. The CPU is original and the thermal gunk, well, I done that whilst taking it apart.

I did reseat the ram and cpu b4 I took it apart, I even took out the dvd drive and hard drive trying to elimiate the problem that way.

If the CPU is faulty would I get the same problem? The CPU is a AMD 64 3200 Hammer.

[Chris1992]

Re: Laptop

If you have a socket 754 board test the CPU in that.

[pcdee]

Re: Laptop

Unable to test

But if the CPU was faulty would I get the same result as I'm getting?

[pcdee]

Re: Laptop

Come on guys,

I'm tempted to just sell it as faulty on ebay

[kc8adu]

Re: Laptop

time to do some real troubleshooting.i would find a board that supports the cpu and ram and test them.
fire it up and see if you have vcore.just measure across one of those cas near the cpu.
compare the reading with the chip specs.
first is to remove any uneeded devices like drives,pcmcia/cardbus devices,ect
make sure all connectors are seated,ect.
i think you give up too easy.
btw i buy and rebuild lots of laptops.

[kc8adu]

Re: Laptop

The laptop turns on, only the fans run and you just get the black screen.

I have tried connecting it to my monitor but no joy, I have bought a brand new psu and still no joy.

shine a flashlight onto the screen and look for an image.ccfl may have quit.
also remember to hit fn crt/lcd with your monitor attached.

[pcdee]

Re: Laptop

After stripping it down to the m/b and not finding anything wrong, I decided to rebuild it and guess what? It bloody works!!!!

It's been stable for 7 days so far

[Malkyne]

Re: Laptop

pcdee:

The 258ka0 is a Uniwill board. Over on the Uniwill forums, you'll find a lot of people posting about 258ka0s that drop dead, or won't POST, and it looks like it's almost always memory-related. I have one that's in the shop right now, and I'm still waiting on a diagnosis. If rebuilding yours saved it, though, you probably just had a loose part or a sinister dust bunny gumming up the works.