Circuits Of The Basic TV and What They Do - Part 1 (Page 1 of 4)
Categories: Televisions and Projectors
When you finish this series of articles on the innards of the basic TV, I hope that this information will give you a basic understanding off what these circuits are called and what they do. Even knowing the basics of how a TV works and what can go wrong can be very useful, even if you do not attempt to repair the set yourself. You should be able to deal with a service technician and understand what they are telling you. More importantly, you're likely to better judge if you are being taken advantage of by a dishonest or incompetent repair center.
For example, someone once called me after getting an estimate on a TV set lacking color from a different service person. The set had a great black and white picture, but simply didn't show color. They were informed that the picture tube was bad! A bad picture tube CANNOT cause a TV to show a good black and white picture, but lack color. I would bet most consumers are unaware of this simple fact. It turned out that the color problem was a 10 cent capacitor I found to be open.
If you do not understand any terminology I have used here, please visit this TechLore thread. If the term you seek is not there, leave a note in that thread and it will be added.
If you need to ask a question about something in this article, leave a question or note in the comment box below. Any questions about a TV set fault or a repair problem will be moved to the appropriate thread. This article is intended to provide a brief explanation of different TV circuits and how they operate. Later in this series I will go over the circuits and how they work in a basic projection TV set.
The set of guidelines below is not meant to scare or frighten you, but to make you aware that working inside of a CRT type TV or computer monitor can be deadly from the line connected power supply, as well as the High voltage power supplies. Please follow all of the safety guidelines.
- Wear rubber soles on your shoes or wear sneakers.
- Set up your work area away from any grounds that you may touch by accident.
- Do not work alone! If there is an accident or you get shocked, someone else present could call for emergency assistance.
- If you need to work on a circuit or measure a component, make sure you discharge the large power supply and High voltage capacitors with a 2 to 5 watt 100 ohm to a 500-ohm resistor, as these capacitors can give you a jolt and possibly stop your heart (this is a high current DC). Never assume anything! Always check it out with a voltmeter across the capacitor. You do not need to discharge the smaller 150+ capacitors in the circuit that are below 35 volts.
- Do not wear any jewelry or anything metallic that could make contact with the live circuitry or any moving parts.
- Never strike or hit the glass envelope of the picture tube, as this would cause an implosion. An implosion would send shards of glass in all directions at a very high speed.
- Always wear eye protection when working on the back of a TV set.
- Always connect and disconnect test leads from your meter or other test equipment with the set unplugged.
- Attempting to repair a set when you are tired or sleepy can make you more careless.
- Do not take shortcuts.
Have the proper tools available
You will need a basic set of decent hand tools to work on most TV sets and to make most adjustments. You do not need the best expensive tools, but cheap tools are worthless. You will need:
- A variety of different sizes of Phillips and straight bladed screwdrivers.
- A set of assorted hex-type socket drivers.
- A couple different sizes of needle nose pliers and wire cutters.
- A good pair of tweezers and dental picks.
- A small screwdriver with a miniature 1/16 inch blade and a non-metallic tip for adjustments.
- A low power, fine tipped soldering iron and fine rosin core solder for the small soldering and unsoldering jobs. A 25-watt iron should be fine for the smaller parts. For those bigger parts; you will need a higher power soldering iron or a small soldering gun.
- A roll of desoldering braid or a bulb type desoldering tool.
More Circuits of the Basic TV Set and What They Do: Part 1 | Part 2