new user- my bad caps

[delphinecrowfever]

Hi, i am new to electronics and i think i have identified a bad cap on my laptop motherboard (laptop is dead) . it has a bunch of numbers on it but after trawling the net i still cant work out what cap i need .

i have included 2 pics. one is of the suspect bad cap and the other is of the exact same type cap located elsewhere on the mobo.

it is the smd that has the following written on the top:

36
47
25G

also it measures about 6mm diameter, height about 4-5 mm (not sure if i measure from base of cap or black plastic mount)

any help would be great, thanks!

[delphinecrowfever]

Re: new user- my bad caps

forgot to mention the motheroard is from my dell inspiron 5100. had it for ages but it but it stopped working a few weeks ago.

[selldoor]

Re: new user- my bad caps

looks like it might be a 25v 47uf - is it surface mounted on a plastic base .
I dont know a lot about choosing a series for surface mounts but this might be good
http://www.digikey.com/product-detai...97CT-ND/295976

[momaka]

Re: new user- my bad caps

What made you conclude that capacitor is bad and what are the symptoms of the laptop? Electrolytic caps in laptops rarely (if ever) go bad, especially in laptops made in the last 10 years or so. The more common problems are bad DC jacks, bad MOSFET somewhere, shorted ceramic capacitor, or bad joints on a BGA chip.

[delphinecrowfever]

Re: new user- my bad caps

The capacitor looks slightly raised up, slightly disfigured and has some brown staining on it (looks like it leaked?). I do not have a meter tester to check it with but would this be the best way for me to test it as well as other components on the motherboard and are there any that are easy to use for a newby you may recommend?.

The laptop shows no signs of firing up, no lights or fans. It had been prone to overheating but had been running fine since i bought a laptop fan tray.

Thanks for replies so far

[selldoor]

Re: new user- my bad caps

Is the adapter ok- does the adapter light stay on when you turn on the laptop.
Have you tried it with and without the battery.

[delphinecrowfever]

Re: new user- my bad caps

yeah I tried it with and without the battery, bought a spare power supply. the light on the power supply is on until I plug it into the laptop, then it goes off.

[selldoor]

Re: new user- my bad caps

As momaka said earlier "The more common problems are bad DC jacks, bad MOSFET somewhere, shorted ceramic capacitor, or bad joints on a BGA chip."
There is a short on the main board The D505 has an infamous ceramic cap that fails
short - remove it and the laptop works. On the 505 it was near the DC jack so perhaps start there and work outwards.