- 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
- 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
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
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
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
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.