Beginner's Guide to TV Repair (Page 1 of 2)
Categories: Televisions and Projectors
Parts and Safety
First off I'm assuming you have a multimeter, if not you can get one for around $15 that will do. A service manual is handy to help you locate some of the components I'll be talking about. Service manuals can ordered from http://www.servicemanuals.net/
Parts can be ordered from Matt Electronics.com or Electronix.com. Call or e-mail them for a free catalog.
Infared detectors for testing remote controls can be found at MCMElectronics.com.
Some parts are mounted on heatsinks and will have a white grease applied to their backside. This is heat sink grease, and you can buy it from Radio Shack.
For testing electroyltic capacitors I recommend the ESR tester model no. mul-3333, it's very easy to use and lists for $49.95 at Matt Electronics.com.
It's easy to get distracted when working on TVs, someone walks into the room or the phone rings and you walk away and forget the set is plugged in. Later you return and you are so busy thinking about the problem that you don't check the power cord. This is a dangerous thing to do. Don't let this happen to you! ask a friend to help with the repairs and keep watch that the power is always removed before you reach inside your TV set to make repairs.
Caution: Be careful when working around an open TV, should something fall and hit the picture tube it could break and impode. Never leave an open TV sitting on your work bench, if you are leaving for the day replace the cover. Don't get lazy and leave it open. One time I left a TV sitting on the shop floor open and it tipped over and the glass neck of the picture tube broke. The owner of the shop was very unhappy with me that day.
Soldering
I also assume you have good soldering skills if not don't attempt to repair your set.
Here's two sites I found that will help you learn to solder.
There are two methods of desoldering, one uses copper braid and the other a solder sucker.
If you're using copper braid brush a little flux on it before you use it.Power problems, set won't turn on
First check to be sure your remote control is working. If your set has a power button on the front panel, then try turning on your set that way. Next, test your remote control using a infared detector. If it's not working change the batteries.
If you set is still not working you will need to remove the back cover and start troubleshooting. After removing the screws gently pull the cover off; never pull hard because you could damage something. If it doesn't come off all the way, shine a flashlight down inside to see what's holding it.
Caution: The main fuse carries 110 volts AC and can hurt you so be sure the set is unplugged. If you're not sure what the fuse looks like go to this website: http://www.electronix.com/catalog/default.php/cPath/253
To check the fuse put your meter on diode check and then place the probes across the fuse. A good fuse will cause the meter to beep. Replace the fuse if it's bad and then plug the set back in while watching the fuse. Turn the power switch on. If the new fuse blows you have a short somewhere.
A common part that often fails in the power supply is the regulator. Take a look at the following wesite to see a picture of what a voltage regulator looks like: http://www.electronix.com/catalog/product_info.php/products_id/9598.
Varistors
A shorted varistor can cause the fuse to blow. These are found in Magnavox, Sony and other sets. To locate this part you will probably need a service manual. They usually mounted on the board close to the ac fuse.
Go to the following sites below to see some pictures of varistors and to learn more about them:
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