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Motherboard blown possibly capacitors? not sure.

4K views 10 replies 5 participants last post by  pwang 
#1 ·
Hello guys,

I have a problem with my desktop motherboard, I cannot be able to switch it on after I have smells the smokes in my room. I have looked on the motherboard which it have went off itself and I was worried what it have happened to them. I have switched back on as it was working fine for few mins and then it went off again. I have smells another smoke and I have switched off immediately without taking any notice.

I have left it off for a while and switched it back on. It was working fine without have any problems before I took my final chance and that was it. The motherboard went off again and it will never switch it back on again, I have tried to figured out where the problem was coming from but I couldn't figure out until today.

I have tested the battery and the power supply, all of them are working fine. I have smells around on the board and I couldn't find out where the problem has been coming from. I have disconnected the hardware and cables from the motherboard, so when I switch it on, the cpu fans will start to spins a little bit as half way but it will stop spinning after I have switched on. I am suspected that if the smokes has been coming from the capacitors which they might have been blown, but I am not 100% sure.

Here's the pictures of the capacitors of the motherboard:







If you believes that you can see any of the capacitors has been blown, I would like you to show me the pictures with red circles where you can see the blown capacitors and I will be happy to replace them without have to buy a new board, otherwise if you couldn't see the capacitors has been blown then it looks like to me that the motherboard is dead and I would have to buy a new one which I am really hope not


In this case, I believes the motherboard is fine because when I switch it on, I can see the cpu fans will spins a little bit before it stop spinning again. I know that the motherboard is working but they won't start to boots because there is not enough power to get in the board which is probably why it is not working. I believes that the capacitors are blown. There shouldn't be a problem for me because I can fix it. :)

I has been using the motherboard for 7 years which it was working great. This is the best one I have ever have and I never has any problems, so I would be sad that if the motherboard is dead.

Any advice would be much appreciate.

Thanks in advance
 
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#2 ·
In the 1st picture, just above the fan/heatsink there are a couple of the smaller capacitors that look bad so I'd replace all six of the caps in that row.

Then in the 2nd picture the capacitor just below the 4-pin connector (below the black multi-pin connector) looks bad. I'd replace that one, then the other three of that size, the two to the right of that one, and the one to the left over near the edge of the board.

But since the board is 7 years old, you might be better off with a new board. The blown caps might have taken some hardware with them when they blew.
 
#3 ·
thanks for your quick response, I am not really sure where is the couple of the smaller capacitors that looks bad in the first picture and in the second picture the capacitor below the 4-pin connector, two to the right and one of the left that looks bad.

Please could you draw the red circle on both pictures and show me how many bad capacitors did you find on my motherboard. I would also appreciate that if any others guys could forward their post on here too which it will be much helpful for me to solve the problem I has got.

However, I am going to buy a new board soon, so it will not really that matter if the replacement capacitors doesn't make the motherboard to work again because I will have the board anyway. If it does works then that is great. :)
 
#4 ·
I think you should replace the board, or the computer.

Except in some unusual cases capacitors do not give off a burnt smell. That is most likely from a regulator chip. But as Jim@HiTek pointed out there are a number of suspicious liking capacitors. The problem is that often a capacitor is bad with no visual indication at all. It may require a great deal of time and trouble to get that board working reliably.
 
#6 · (Edited)
How do you know that the problem is most likely to be coming from a regulator chip?

I will be happy to replace that, so hopefully it will help me to solve the problem.

As for capacitors, some of them are bulging and leaks, so I will have to replace them as well?



Same as above. A Mobo replacement would be a good option.
I have brought the spare mobo, if I try to soldering the caps on the mobo and if still doesn't work then it doesn't really matter because I have got the new mobo anyway. You will never knows what will happens if I soldering the caps on the mobo and replace the chip, it might works so who knows.
 
#7 ·
In my experience the components that are most likely to burn are resistors, semiconductors, and other components that dissipate considerable power. On a computer motherboard that usually means semiconductors. Of these, regulator chips are most likely to burn. There are exceptions. The part that is burning may not be the source of the problem. The actual source of the problem may not be visible, even to an experienced technician.

Any capacitors that show signs of bulging, leaking, etc. are bad and would need to be replaced. But as I said before many capacitor failures (and other components as well) have no visible signs whatsoever.

Troubleshooting this kind of problem can be very time consuming, even for an experienced technician with access to proper test equipment and service information.

Replacement of components on a modern circuit board is not a trivial thing.

My advice would be to replace the motherboard, or better yet, the computer.

My comments are based on 30 years experience servicing electronic equipment. Computer motherboards are rarely serviced at this level and few computer technicians are qualified. Replacement of the motherboard is usually more cost effective.
 
#8 ·
Well, I had a look on my motherboard and none of the regulator chips have been burnt. I would like you to take a look on the two pictures that I have post on my first post and show me where you can see or believes that the chips is burnt?

As for capacitors, I will definitely replace them but I need to know the correct type of capacitors before I will replace them.
 
#9 ·
You smelled smoke. Like has been said, usually that indicates a blown device and not necessarily a capacitor. But it often leaves difficult to find evidence on the part itself. If you don't have the equipment & skill to test the various devices, with and without power, it's not reasonable to spend a lot of time on the board.

As far as the capacitors go, each one has the value, working voltage, polarity, & temp rating printed on it's plastic cover. That's basically all you need and you can use any manufacturers part that meets those ratings.
 
#10 ·
I am sure you are familiar with the saying: "A little knowledge is a dangerous thing."
It is very appropriate here. Even with the best information you could receive on this forum, that is what you would have - a little knowledge. You have no idea what you are getting into. You might get lucky with the repair, but the odds are against it.
 
#11 ·
Blown components can't always be visible. If its is an ecap failure then the bulging top will indicate failure. You will still need an esr meter to check the rest. Now the hard part. Only by voltage testing of test points can you detect regulator problem if any and this has to be done live with power applied to the system. Finally even with your digital meter showing acceptable voltage present you still have to confirm that there are no glitches anymore with the use of a scope. All said and done, replacing the board is the most economical and practical thing to do. If you want to start learning basic electronics I would suggest that you attend short technical workshops to be on the safe side since you will have to work with live energized circuit to learn more.
 
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