MY tv will not always turn on anymore; it does not matter whether I try with the remote or manually. When it does come on, it works fine, but it could take 100 times of pushing the button before it d

SOURCE: On/Off blue light blinking, TV won't come on.

Ur power ic inverter board is dead.
U need new one.

Testimonial: "Thanks for the advice. Will try it."

Steve Allison

• 5569 Answers
• Posted on Jul 16, 2010

SOURCE: Green light blinking and TV will not turn on

In many sets, this is an indication of a failed power supply voltage. There are at least two supplies in every set; one is active always so the set can receive commands from the remote and requires minimal power and rarely fails. The other is turned on when the set is to be used and this one, is the likely culprit.
The type of supply used in modern sets is called a 'switched mode' power supply that operates at higher (than audible) frequencies in the range of 50,000 cycles and up. The supply first makes DC voltage from the AC input of 100-220 volts, then chops it at the elevated frequency. This design is much more efficient than the older type of 'linear' supply but is more complicated and critical in the quality of parts used.
These modern supplies are fussy about the quality of certain components and most will eventually fail due to crappy electrolytic capacitors, a part used for filtering and in feedback paths and they, by nature, don't really like these higher frequencies; they tend to break down chemically and lose their value until finally not performing as capacitors any more. This causes the supply to fail at starting up and more rarely, to cease operating while in service and sometimes develop internal losses that cause it to heat up and burst or at least bleed chemicals either of which causes their final death.
There are capacitors that are more resistant to this kind of decay but cost 2-5 times as much as common types and with the severe price competition in consumer electronics, manufacturers save where they can and use parts that will at least survive the warranty period.
I suggest you contact the service center for your area and inquire about the cost of board repair or replacement. If the latter, keep the failed board since there are small shops (I was one before retirement) with the skills to repair these at a more reasonable cost.
Before opening the back of your set, pull the plug and allow to sit, preferably overnight. There are nasty voltages inside that you want to avoid. The main power supply is often on a separate board, will have larger-than-average parts on it, with cylindrical parts (mostly capacitors) and some larger squarish parts (chokes and transformers) and most likely a 'heat sink,' a finned aluminum structure with parts attached to it. Look for a tag with a part number on it and have this available when you start looking for service or new board.
These assemblies are nearly always only plugged into the rest of the set with clearly dissimilar plugs so incorrect connections are somewhat prevented.
If you are unsure of yourself, take several pictures of this area before disconnecting anything that you can then refer to if uncertain. Remember, many assemblers of most of these just recently came in from small farming villages in Asia so assembly is kept simple. Good luck-

SOURCE: LT-42P300 won't turn on. When I plug it in I

Hello,

You might wish to unplug the TV for an hour or more. If this power reset does not allow the TV to turn on component failure is indicated. These sets are assembled using the wave soldering process they are known for having cold solder connections.

The safety circuitry shuts the TV set down or will keep it from turning on when it detects a problem. This model of TV has over 2,000 parts, which includes millions of transistors inside the integrated circuits. The capacitors will change value, leak and become defective. Resistors will change value and burn. Diodes and IC can go bad.

This may have a domino effect and cause other parts to fail. Replacing one defective part may make the TV operate for a short time but the part will fail again if the parts that caused the failure to begin with are not replaced.

The only way to know for sure which parts that are no longer within factory specs and for a proper repair all the electronics must be diagnosed by someone with the correct electronic test equipment specifically designed for TV service and the skills to use the test equipment. I wish I could tell you there was a quick fix or button to push that would fix the TV but that is not the case or the solution needed to get the TV operating correctly.

The issue you describe is consistent with a power supply board issue. This is the board where the AC goes to. This problem may have occurred as a result of irregular power supply, or excess power supply or power surge.

The TV is receiving current but cannot circulate or transfer the current to other necessary part of the TV because of the defective power supply board. You might be lucky it's just a blow fuse. Also a defective transformer can cause your TV not to power on.

All these can be checked on the power supply board.

But more often bad capacitors causes problem on the power supply board. I do not think the power board needs replacement, rather those defective capacitors is causing this issue. Open unit up and take a look at the power supply board.You will probably see one or more electrolytic filter capacitors that are bulged up in the top-not perfectly flat like the others.

The value of these capacitors will be different, most likely they will be somewhere around-820 to 2200uF/25 V( or /10V sometimes)

You can replace them with same values but I would recommend the voltage rating to be higher(like 35V for an original 25V) for reliability purposes.

What happens is,these bulged top capacitors will cause a low and unfiltered DC voltage=main board will malfunction(the relay will keep clicking until the caps are holding enough charge to bring the voltage up over a threshold point).

You can buy these capacitors at any Fry's or Radioshack store or you can order them online at vendors like "mcmelectronics.com"(look for electrolytic capacitors). After replacing these capacitor(capacitors) most likely the normal operation will be restored. Or you can by a refurbished complete power board to save you some stress.

Note: There may be also some other causes for this symptom ,like a defective T con board ,or main board,but the bulged top capacitors are the most common cause for this issue.

If you don't know about TV repairers, take the TV to the nearest repairman to fix the fault for you. Also, note that TV stores a lot of current, so wait a while before opening the TV back cover.

I hope this helps.