Is your desktop computer running slower than normal? Does it randomly or constantly freeze up or restart? Or maybe it doesn't boot to the operating system or even boot at all. If so, your computer could have a failed capacitor.
Every computer repair shop has their own set of standard procedures and we are no different. The very first thing we do when someone brings in a desktop computer is check for blown capacitors. With a quick visual inspection, we can spot a costly computer repair. And you can too. Here's how to inspect your desktop computer for failed capacitors.
Symptoms of bad capacitors
Now before you go and take your system apart, let's take a look at the symptoms of a failed capacitor. Does your computer have any of the following problems?
- Runs slows
- Randomly freezes up
- Randomly / constantly restarts
- Won't boot to an operating system
- Won't start at all
If so, it might be worth the time to take a look inside your computer.
Types of capacitors
Visual differences between water based and polymer based electrolyte capacitors
There are primarily two type of capacitors used on computer circuit boards (motherboards, graphics cards, etc.), water-based electrolyte and polymer-based electrolyte. The majority of failures I have seen are with water-based capacitors, but polymer-based do fail too, just not as often. During the years of 1999 thru 2007, millions of faulty water-based capacitors were produced by some Taiwanese manufacturers. The electrolyte will evaporate and turn into a gas, thus bulging the case, and in some cases, leaking.
Checking for bad capacitors
Top view of a row of failed capacitors
Side view of a failed capacitor
The following can be performed with the computer in-place, provided you have enough room. If not, you will have to move your computer to a location that does. Take a photo of where everything goes first, then completely disconnect all cables that attach to it.
- Power down your computer and
Open the case.
Remove any obstructions, like fan shrouds, so you can view the entire motherboard and other add-in cards.
Using a flash light, visually inspect all capacitors on the circuit boards (motherboard, graphics card, etc.). You may need to physically remove some of the add-in cards to inspect them. Visual symptoms include:
- Remove the power cord from the back of the power supply (in-place inspection)
- Disconnect all cables (relocated inspection)
- Bulging or cracking of the vent on top
- Casing sitting crooked on board as the base may be pushed out
- Electrolyte that may have leaked out on to motherboard (rust colored)
- Case is detached or missing
What to do if you find a bad capacitor
If you do find a bad capacitor, there are three (3) options. First thing, if your computer is still operable, backup your data ASAP (see links below). There are a lot of factors involved in deciding which option to choose, age of the system and cost being the two major ones.
- Repair the motherboard
You can replace the bad capacitor yourself (see link below) or have a trained professional do it for you.
- Replace the motherboard
EBay is a great place to find a refurbished motherboard.
- Replace the computer
If you've been looking for an excuse to get a new computer, you just found one. Or maybe two or three.
For more information on failed capacitors:
Capacitor plague - Wikipedia
For more information on how to replace failed capacitors:
Recapping your own motherboard - Badcaps.net
For more information on how to backup your computer:
Windows XP Backup
Windows Vista Backup
Windows 7 Backup
Windows 8 Backup