How To Recognize Flawed Capacitors
Our capacity gauge shows 1000µF, indicating that this capacitor retains full capacity.
An exploded exterior reveals a broken capacitor. A lumpy top or even an opening at the predetermined breaking point are clear indicators that a capacitor is about to die, if it hasn't died already. From time to time, the rubber plug, closing the capacitor on the bottom, gets pushed out by gas pressure inside the body. It is especially difficult to detect broken capacitors, whose electrolyte drained over time and didn't leave any traces on the aluminum body. The dryer a capacitor, the less capacity it has to store electric charge. You definitely need a capacity gauge (see picture) to measure the capacitor. You can get these devices for less than $30. We use a Digitek DS-568F, which was sufficient for our purpose and at less than $40 it was affordable as well.
Welcome to the Emergency Room
We found a several year old board from MSI in our shelves. Defective capacitors are a problem with mobos from just about all manufacturers. So, please don't take our choice of product as an indictment of MSI. The motherboard just happened to be hanging around our lab, so we used it.
Due to its dual processor sockets, we believe that the K7Master is well suited to reanimation. Exchanging this motherboard for another would entail replacing the two processors as well as RAM (registered DDR memory in this case), which would be an economic nightmare.
We could not see if all capacitors had deteriorated. However since they were all of the same kind, we assumed that all of them needed replacement. So we began a search for 26 substitute capacitors with equal capacity.
Current page: How To Recognize Flawed CapacitorsPrev Page When Capacitors Spring Leaks Next Page How To Buy Substitute Low-ESR Capacitors
Stay on the Cutting Edge
Join the experts who read Tom's Hardware for the inside track on enthusiast PC tech news — and have for over 25 years. We'll send breaking news and in-depth reviews of CPUs, GPUs, AI, maker hardware and more straight to your inbox.
Recognizing of broken capacitors is not so simple in some cases.Reply
Sometimes (very often in my case) have capacitor its nominal capacity but it has high serial current. When you connect DC voltage of capacitor nominal value and capacitor have some serial current throught it, then it is broken. Only charging current is allowed (short current peak on connect).
Sorry for my english.
Good article. I have personally made this repair sucessfully many times using only a basic hand held solding iron and hand held desolder pump.Reply
Like you say the motherboard sinks away the heat fast. You need an iron with between 70 and 100 watts and a large flat tip. If it spans both solder points of the cap its really easy :)
Just heat and gently pull the cap out from the other side of the board. Then clear the holes with the heated pin method or use a desolder pump. If you heat the hole on one side and use the pump on the other side it should clear easily.
Only other thing to note is. Be QUICK, practice on some junk board first, you dont want to burn a big hole in your board or lift of the tracks.
Im sure most people don't have a professional solder/desolder station. These cost at least $160 usually more.
Another trick. Assuming the old caps are dead and of no further use. Pull them off thier leads.Reply
If you pull a electrolytic capacitor hard the leads will pull straight out of the body of the cap.
Leaving just the leads sticking up. Its now much easier to remove becuase you can desolder the leads and remove them one at a time.
Just trim the leads sticking out of the bottom of the board then heat one at a time while applying slight pressure to the capacitor towards the other lead. They pop right out. I use thecapking for capacitors online, fast free shipping.Reply
I use the Weller WLC100. It's consumer DIY soldering station, but more than meets the needs for motherboard soldering. Runs about $50. I've done 50+ boards easily with this station, but I use a precision tip instead of the big tip it comes with (usually run about $10). I also recommend Mouser or Digikey for capacitors, though beginners may find these sites overwhelming. TheCapking is a good place to find capacitor kits for common motherboards with faulty capacitors, and the site has diagrams in case you get confused where the capacitors need to go.Reply
ooowowwwwww nice i am verry happy he he he he....... i likedReply
I Turned on a computer that had been working. A short "pop", a fairly intense burning odor, and later I found a capacitor (I presume) on the bottom of my computer case:Reply
Here is a pic of the Asus P5-K. The green arrow points to where the capacitor used to sit.
First of all I'd like to know if it is indeed a capacitor and if not, what it is. Whatever it is, can I get another, solder it in and have any hope of fixing this board? I'm really clueless, if you can't tell. Any help would be greatly appreciated. This could be an opportunity for me to learn something.
I have a MSI mobo which I repaired some months back...replaced 2 caps. Lately, the same symptoms re-occured..pc starts up, fans run, lights light up but nothing else..no sound, no bios, no display. I replaced the same caps again thinking it might be malfunctioning but still nothing and no signs of any other failure. Any advice? My pc is a Acer Veriton M464 duo core.Reply
Once you pull a mother board for any bad caps, you should replace them all. The caps are cheap compared to the down time and frustration. Some caps can fail with no obvious signs from the outside. My advise would be to change all the old caps with new low ESR Caps.Reply