Tv Cycles Off And On Spontaneously

Although I'm not sure what you are asking exactly when you say the set will not turn and stay "off". I'm going to assume that the set doesn't properly turn "on" and it cycles on/off many times trying to start up completely. I'm going to gues that you are having a "ballast" circuit problem or the new lamp has failed (or something is wrong with the connection between the lamp and the ballast).

Here is a brief over view of what has to happen for a DLP rear projection Samsung TV to work correctly.

There are many things that need to happen before the lamp will start up. The power supply must develop all the needed voltages required by all the rest of the circuits, the cooling fans must be running at the correct speeds, the lamp door switch must be closed (interlock switch), the ballast circuit must be able to develop the 5000 volts to start-up the mercury vapor lamp. There should be no weird noises pointing to the fact that a fan or the color wheels motor bearings are starting to go bad.

The normal failures are the lamp and the color wheel. Unfortunately there is NO way to test a lamp. I have seen nearly 100 lamps come into my shop that has failed in less than a month, and many that didn't last one full day. These lamp you buy off the web are many times factory seconds. I have had some customers send back a lamp two, three, and four times before they got one that lasted through the warranty. Our shop only buys from the manufacturer.

When you turn on this DLP HDTV the fans will start up first ant then the color wheel will spin-up. If the color wheel doesn't get up to the 1800 RPM and maintain that speed then the lamp will not get to enable pulse. unfortunately after three attempts the set will shut down and the indicators will blink telling the customer to change the lamp, and of course after the customer does it, the problem remains the same. The microprocessor is located in the signal cluster and all it knows is that the lamp didn't light up correctly, so it gives the change lamp LED indicator blink

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TV Dan

Let's start with the main problem: - Your TV is experiencing a technical problem that is very common in older sets. There is a printed circuit board in the TV that has electronic components soldered on to the board. The connections on the board crack over time and create "open" connections. These "open connections" then create undesirable voltage fluctuations in the circuit. There are electronic components such as "Silicon Controlled Rectifiers", "Microprocessors", "Transistors" that require a stable voltage to function properly. When one of these components such as the microprocessor loses it's required voltage (even if just momentarily), funny things happen. The TV shutting down is a very common problem when the "Vertical or Horizontal Output Transistor fails to operate correctly for a second or two. Rarely is it an "overheat" problem. Second problem: DO NOT OPEN the back of the TV unless you are an experienced TV repair person. The reason why? There is a transformer in there that is called the "High Voltage Flyback transformer". It sends over 10,000 Volts to the back of the picture tube. The picture tube has a phospherous coating on it, which stores residual voltage on the coating. EVEN AFTER you unplug the TV, there is a strong residual voltage present on the back of the TV which must be discharged from the CRT. Even after 24 hours, there is still enough residual voltage to give you one hell of a good shock! There is a way professionally to discharge that voltage at the service center so they can work on the TV. You don't have that ability at home. There is nothing you can do as a consumer to fix your issue unfortunately. You will need to take it in and have it looked at. You will have to decide if a 12 yr old Sharp TV is worth fixing. Hope that helps, good luck!