Repair Your Electronics by Replacing Blown Capacitors

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Introduction: Repair Your Electronics by Replacing Blown Capacitors

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. 

Step 1: 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

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.

Step 4: Remove the Old Capacitor

Make a note of the polarity of the old capacitor, and mark the exact values you'll need for the replacement: capacitance and voltage/temperature ratings (these may be written on the part itself, or you can look up the part number).

Press the tip of a heated soldering iron directly onto the solder joint on the back of the circuit board that is holding the old capacitor down.  Hold on to the capacitor itself with your other hand.  As the joint melts, you can feel the tip of the iron fall into the hole of the circuit board.  As soon as it does, pull that side's wire lead out of the board.  Then repeat with the other side.

This can take a bit of trial and error.  The goal is to dig the very tip of the iron into the joint so that the solder in the hole heats and melts.  If there's too much solder for your iron to reach the hole itself, you may want to use a soldering wick to get rid of some of the excess.

Also, be aware that some manufacturers use solder that cannot be melted by a typical hobbyist soldering iron.

Step 5: Insert the New Capacitor

Trim the leads of the new capacitor so that they are both even, and will sit at about the same height as the old capacitor.

Position the new capacitor leads at the holes where the old capacitor was, with the correct polarity.  Just like before, press the tip of the soldering iron directly onto the joint in the back of the circuit board.   As soon as the tip falls into the hole, press the wire lead through the hole, then remove the iron.  The old solder joint will solidify around the new part and hold it secure.  Repeat with the other side.  Add new solder to the joint if necessary.

Step 6: Working Now!

Replace the circuit board in its case and test the power and output.  The electronics should work now!

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47 Discussions

0
user
TomF143

Question 5 months ago

Hi. I'm being challenged by this board sitting in a "bathtub" filled with about 1/16" of clear latex. Does anyone have experience on which route should be taken? I could cut away the plastic behind the board but the goo has me a bit concerned. The caps are 11mm tall so I can get my tweezers around them, but will they release without damaging the surrounding board?
The other option would be to attack from the top -- grind, peel, pluck, and vacuum -- leaving just the leads. Has anyone done this with positive results? I was thinking about soldering some sleeve connectors for future change outs of these caps without pulling the board again.
It's the CPU for a Rheem tankless water heater (and I really hate cold showers, especially in winter!).
Any insights are very much appreciated, and I'll send some more pictures if anyone is interested in The Latex Challenge.

IMG_20180204_221325.jpg
0
user
Osk33

6 months ago

I wanted to replaced two capacitors on my Samsung circuit board. In the process I accidentally removed the copperhead pads. Can I still solder the new capacitors and how would I do it? Thanks in advance

Circuit Board Copperhead.jpg

250v185j cl21 capacitor burned from old portable rechargeable fan what can i do.. pls help me for replacement capacitor in india

Hey guys. I have a craftsman/liftmaster garage door opener model 41A5021-1l. Had a lightening storm, tripped a breaker, and now it's dead it seems. Completely. Even the GFI outlet it was plugged into needed replaced. Pulled the board out and noticed maybe two smokey areas on the board. I can buy a new board for $75 but I don't think this issue is a bad sodder joint. Here are some pics. Any ideas? And on the blue capacitor (not really near the smokey area on the board, the teeth are super pushed out? Ideas?, Kinda a newbie. (i can also add more photo's if need be)

home-design (2).jpghome-design (1).jpghome-design.jpg

I have a 65" Panasonic Plasma TV model TC-P65S2

Last night I heard a bang like an M80, and the TV turned off. I unplugged it from the wall, and while doing so, smelled burning stuff.

I took the case off today and checked all the capacitors, and they looked great, except the two 230v1000 in the picture, (closest foregound, and behind at medium distance) they both had slight bulges. Is it likely they both blew at the same time and produced one bang noise?

19059793_10213789139107832_22173498233094511_n.jpg
3 replies

Also, I have a 7-blink error code, which indicates a problem with the Driver SOS 2 SU / SD / SS Boards (SC floating voltage area)

I just disconnected the Y-sustain board(s) and plugged the TV back in and it went from 7 blinks to 6, which as indicated on a youtube video I found, that the Y-sustain board is the problem, but I'd like to narrow it down further as the Y-sustain consists of three boards, the 5175, 5184 and 5185, each of which costs about $100 and is out of stock every where

I have confused further by finding a diagram showing the 5184 and 5185 boards form a buffer board...

i have a samsung plasma tv model; ps42b430p2w that was making a clicking sound and not powering on. all capacitors are good not physical damage. so i change the bad that i assume was bad . after replacing the board LJ41-06613A. the \Tv is turning on now no clicking sound, but it stays blank no pictures. what can i do

1 reply

sounds like you need to replace the controller board as well? Maybe you had a voltage surge or something and it knocked out both boards?

Question... Please help! I pulled my capacitors out before reading how to remove them (I know... Stupid) and have all the tools and new capacitors now. How can I fix my problem? I can still see part of the old wires in the hole. Should I take a sweezer and heat up the back and follow through with the removal instructions or just solder new ones onto the old wires? Thank you to anyone who can help me with my dilemma!

4 replies

Did you get it sorted out in the end? I haven't done mine yet. My son who is an electrical engineer but lives on the opposite extreme of the continent warns me that replacing capacitors is much more difficult than what most tutorials like this one would have you think. I'm 71. I doubt if I have the quality of eye sight and steady hands he feels are needed for this work. He wants me to let him buy me a new tv for Christmas.

I did and it works great. Only issue now is it turns on by itself in the middle of the night. Ha! No idea why

i have a samsung 32 inch smart led tv it turns on with image on the screen with sound but no back lights are working could this be a power board problem

1 reply

backlight bulb is probably burned out. I don't know anything beyond that

I did it! Yay! Works like a charm now

I have a sterio in my living room but current went into it and now it has stop coming on. Someone please help me.

On the body computer in my car it looks like a capacitor has failed . This is of the design known as "Case E" I cannot see any simple way to remove the faulty capacitor - and therefore also any way to easily re-solder the replacement - how is this type of capacitor attached?