Need small help on this - Page 1
Forum section: electronics / repair

author: mrartuka
author_rank: Contributor
timestamp: April 10, 2016, 08:07:44 pm
content: Hello everyone,im sry if im writting in wrong category but really im noobDont know who else to ask as i cant figure out what is this component.Its not directly related to general electronic,but profesionalls like you should know.Basically what happened is that my motherboard stopped working,just like 1ms click and thats all.So i removed cpu and tried to turn on (tought it was dead cpu), and what happened BOOM, smoke coming from cpu socket.After closer look i found that one component had like small hole in it,probably coz it burned out, and now trying to figure out what is that component and why did it died.It have 1 joint from left and right side and its located directly in center of cpu socket.Here is picture so maybe its easier for you to figure out.It say on it: 100 18GBKSo if someone know answer to this thank you.

author: Elrod
author_rank: Contributor
timestamp: April 11, 2016, 07:45:28 pm
content: Possibly a tantalum capacitor. They have been know to just get tired of living and will short or burn or explode.

author: mrartuka
author_rank: Contributor
timestamp: April 11, 2016, 08:06:43 pm
content: Quote from: Elrod on April 11, 2016, 07:45:28 pmYeah, i went to irc chat on eevblog end some guys told me that.Today i replaced that cap,but for some reason that cap went BOOM.So it can be only fault somewhere else, or maybe we didnt read ratings correctly.On original it said: 100 18GBK DSo i found another one, but on this it was saying 100 2V.So my guess would be that 18GBK means 18V? Can someone confirm that.

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 11, 2016, 08:08:44 pm
content: Quote from: mrartuka on April 11, 2016, 08:06:43 pmI have no idea what 18GBK means but 18V on a CPU socket is not what you would expect.

author: mrartuka
author_rank: Contributor
timestamp: April 11, 2016, 08:13:12 pm
content: Quote from: PA0PBZ on April 11, 2016, 08:08:44 pmWell yeah,thats why i tried this 2V, but this was went boom like if you give it 220V on 2V cap -_-So confusing this. I really hope so Dave will read this and give some info, he is my last hope

author: PA0PBZ
author_rank: Super Contributor
timestamp: April 11, 2016, 08:19:58 pm
content: Can you measure the voltage there (without a CPU in it)?

author: mrartuka
author_rank: Contributor
timestamp: April 11, 2016, 08:22:49 pm
content: Quote from: PA0PBZ on April 11, 2016, 08:19:58 pmIm not sure should i turn it on now without this cap, kinda dont want to make it dead 100% .Well currently cant measure,as i dont have multimeter and now its night here in Bosnia.Tomorrow right when i woke up il go to friend and measure it.This MSI support....

author: Wilksey
author_rank: Super Contributor
timestamp: April 11, 2016, 08:28:55 pm
content: 1.8V?Probably 100uF or 100nF

author: mrartuka
author_rank: Contributor
timestamp: April 11, 2016, 08:37:04 pm
content: Quote from: Wilksey on April 11, 2016, 08:28:55 pm1.8V or 18V ,its hard to find info on those markings.So if it was 1.8V and i used 2V it shouldnt boom like that.Unfortunally MSI support still didnt repond anything related to this,so im fcked...

author: SeanB
author_rank: Super Contributor
timestamp: April 11, 2016, 08:37:55 pm
content: 100uF 2V most likely, but it went boom because it has had 12VDC applied to it from a failed CPU voltage regulator with shorted high side mosfet. Would be any of the 6 there top right of the board.

author: mrartuka
author_rank: Contributor
timestamp: April 11, 2016, 08:46:56 pm
content: Quote from: SeanB on April 11, 2016, 08:37:55 pmOk your answer have sense. Are u Dave's brother KappaWell it seems this mobe will stay dead as i have no idea how to test this, and tech guys in my country are bad almost like me.Thanks everyone

author: SeanB
author_rank: Super Contributor
timestamp: April 11, 2016, 08:56:49 pm
content: No, just have had a few motherboards which did the same high side driver go bang and blow the CPU as well. The older Pentium processors were pretty much unkillable, I even used one as an electric fence tester, and it survived a good number of belts with 8J of energy. I eventually killed it with 12V applied to half the pins and the other half grounded till they melted off, and I would not be surprised that burnt pins was the only failure. Not so the newer ones.

author: Wilksey
author_rank: Super Contributor
timestamp: April 12, 2016, 01:12:06 am
content: It wouldn't be 18v, it would be a CPU core voltage more than likely, which is usually (?) around 1.2 / 1.25V? So, a 1.8 / 2V rated cap would make sense. I must be honest, I am not 100% sure what voltages the CPU use, I presumed there was a kind of PMIC onboard somewhere.

author: Jonny
author_rank: Regular Contributor
timestamp: April 16, 2016, 10:05:09 am
content: No offence, but you did put it in the right way around?

author: Fulcrum
author_rank: Regular Contributor
timestamp: April 18, 2016, 09:54:10 pm
content: I recommend you power up the motherboard without the tantalum capacitor in, and measure the voltage it is being applied. If you have an oscillator, or can borrow it, also check out its waveform. Could be, as others have said, that one of the CPU power supplies have failed and is supplying a too high voltage. If that is the case then the CPU is likely dead too! Unless you have some experience with debugging electronics I recommend just scrapping it and getting a new mobo.

author: mrartuka
author_rank: Contributor
timestamp: April 20, 2016, 09:18:11 am
content: Quote from: Jonny on April 16, 2016, 10:05:09 amDuh... well probably pc wouldnt work for 5 days

author: mrartuka
author_rank: Contributor
timestamp: April 20, 2016, 09:20:58 am
content: Quote from: Fulcrum on April 18, 2016, 09:54:10 pmTomorrow il get multimeter delivered and il check that. As for cpu, he is still alive tnx god. Il post tomorrow again

author: mrartuka
author_rank: Contributor
timestamp: April 21, 2016, 09:01:25 am
content: Quote from: SeanB on April 11, 2016, 08:37:55 pmWell it seems i found one bad mosfet.Dont know did i test it corectly, but every other mosfets gave me some values, except this one.Tried in continuity mode, and it beeped on overy leg. Sry for my bad english.Well gl to me with replacing that mosfet, it will be pain in the ass

author: SeanB
author_rank: Super Contributor
timestamp: April 21, 2016, 07:43:35 pm
content: Going to be almost impossible to unsolder as the board under it will suck all the heat you can apply with any soldering iron. So you need to both preheat the board area to around 100C then heat up the component to melt the solder. Only doable if you have both a preheater plate and a soldering iron capable of putting a serious amount of heat into a small area.

author: pinyoro
author_rank: Contributor
timestamp: April 21, 2016, 10:51:07 pm
content: Quote from: SeanB on April 21, 2016, 07:43:35 pmThat is when JBC soldering irons shine

author: Fulcrum
author_rank: Regular Contributor
timestamp: April 22, 2016, 10:12:01 am
content: Quote from: mrartuka on April 21, 2016, 09:01:25 amGood luck with that! Let us know how it goes.

author: mrartuka
author_rank: Contributor
timestamp: April 22, 2016, 10:53:34 am
content: Well my friend have hot air gun or what is called.But it will be kinda hard to remove that mosfet coz its surrounded by caps.Values across other mosfets are different, so i dont know which mosfet to put in.Here is image with my readings across those 6 mosfets (using diode mode) if someone knows.Shorted mosfet is: NIKOS P0903BDbtw i have new mobo, but cant just throw away mobo that can be fixed.

author: mrartuka
author_rank: Contributor
timestamp: April 25, 2016, 04:48:02 pm
content: Quote from: Fulcrum on April 22, 2016, 10:12:01 amUPDATE: replaced bad mosfet, tested without tantalum capacitor.Voltage coming to that cap is 1.06V ,tomorrow il get another tantalum cap and solder it on board

author: mrartuka
author_rank: Contributor
timestamp: April 26, 2016, 10:29:26 pm
content: Quote from: SeanB on April 11, 2016, 08:37:55 pmSry for quote you again, but wanted to share news, and thankfully to you and others, mobo is alive!Few minutes ago soldered that tantalum cap,turned on and here i am writing from it.Not sure what caused mosfet to failSo scared that it will die again.CPUZ showing voltage around 1.138 - 1.228 depending on core speed which is adjusting automatically.Once again Thanks everyone <3