Instructables

Repair your electronics by replacing blown capacitors

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Checking for blown capacitors in your malfunctioning electronics is fast and easy if know what you're looking for.  Replacing one part at a couple dollars a piece is much cheaper than replacing an entire monitor for hundreds of dollars!  Monitors, digital converters, and other video- related electronics commonly have power issues that are caused by faulty (read: low quality production) capacitors.  Common symptoms include:

- Unit won't turn on
- Unit won't return from standby
- Unit turns on and off intermittently
- Screen flickering or distorted
- Lines across the screen

If you're experiencing any of these, it's worth taking several minutes to check your circuit board capacitors. 

 
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Step 1: Tools needed

Picture of Tools needed
Checking the capacitor just requires your eyeballs but replacing them requires a few tools:

- Screwdriver, hex wrench, or whatever's needed to open the case
- Soldering iron
- Replacement capacitors (you will find the values for this in the following steps)

Also optional but helpful is soldering wick, which is available for fairly cheap at Radio Shack.

In this example I'm repairing a digital TV converter box that will power on, but does not activate from standby.

Step 2: Open the case

Picture of Open the case
Most important: power off and unplug your unit!

Using your screwdriver or other tools, open up the electronics case so that you have easy access to the circuit board.  If you're having trouble, look up the manual online to find out where the various screws and tabs are to open the case.

Bring it up the light so you can see the electrolytic capacitors easily.

Step 3: What a blown capacitor looks like

A busted capacitor can be obviously broken (leaking brownish fluid, corroded, or with the leads severed), but sometimes it's subtle. The top of a blown capacitor will be slightly bent outwards in a convex shape, rather than flat or slightly indented inwards like a working capacitor.  See the photos above for examples. 

Think of it like a vacuum-sealed glass bottle.  When the seal is intact, the bottle cap is flat, and when you break the seal, the bottle cap pops up.  That subtle "popping-up" is exactly what you're looking for.
jmichaels46 months ago

Is it possible to have a blown capacitor WITHOUT any visible change in it? That is, no distortion of the top, etc.?

Yes! Use an ESR meter and/or capacitance tester to check (they are not the same as a multimiter though some of the very expensive ones will come with the functionality) the capacitors. They run about $80 for a decent ESR meter. If your electronics aren't worth that much I would simply replace them, though.

iq2017 months ago
Discharge all capacitors in the vicinity. It's best not to assume they're all discharged.
jgeidl7 months ago
Nice job. I love hints.
raptor4021 year ago
Hello, sir/ma'am

Your instructable is wonderful. I have a question: I have an XBox 360 slim with a 100-127v input power supply. In my country, the wall outlets are all 220v, so I was using a step-down transformer with the console. Unfortunately, I tried out a smaller converter without reading that it was not transformer based. To sum it up, there was a bang and some smoke.
I opened up the adapter and found that one big capacitor had burst open (that was my first guess as I had seen a capacitor burst with my own eyes, and that was my own doing) and the electrolyte was spread around. I cleaned up the electrolyte and tried the adapter. The console would work for a minute and then shut down, implying that the rest of the adapter is function.
My question is: will replacing the capacitor fix the adapter and make it usable again?
rbennett81 year ago
i can vouch for this i had o recently recap my 26" lcd tv due to it turning on and off intermittently

i recommended this site they will help you out a lot with the process

http://www.badcaps.net/

http://www.badcaps.net/forum/

also the desoldering wick from radio shack from my experience is junk

this one is good i have not had a problem with it yet
http://www.drillspot.com/products/1429031/Tech_Spray_1811-5F_Desoldering_Wick?s=1

crowman732 years ago
I'll definitely use this tip in future, thanks.
thank you sir, very helpful.

i had a DVD player stop working, turns out it blew the switching power supply IC, and a fuse as well. I replaced them and the unit still didnt power on.

i had overlooked a couple of blown caps, so thanks for reminding me to take a second look! all is functioning well
Dr.Bill2 years ago
I always suspected the tops of the caps were scored for a reason.
Horsehockey2 years ago
You say to note the polarity of the capicator. Trying to determine the polarity of capicators, especially on well pump motors or other outside erquipment, has always baffled me. Maybe the little blue capicators have the polarity on them.
I have asked many highly intelligent electronics technitians how to determine if a capacitor was bad. Their reply was that if they thought it could be bad they replaced it. You are the first person I have seen that has come up with a simple way to dewtermine a bad capicator. Thanks for sharing.
fhidiort (author)  Horsehockey2 years ago
Usually electrolytic capacitors have a stripe with minus signs down the side that indicate the negative lead. You can see in the Step 5 picture the blue capacitor has a black stripe with blue minus signs- that's the negative end. Also on some circuit boards (including the one used in this example) the polarity is marked on the board itself with a little plus and minus sign.
dimmaz882 years ago
Awesome instructable. The trick for identifying the broken capacitors is great, I've always wondered how to do so.

Thanks for sharing.
coming from non electronics i was really glad you explained the thing with simplicity. Loved it !
fhidiort (author)  dimmaz882 years ago
Glad it helped!