coby tftv3227 turns on then off

[pac.attack76]

Turns on and display comes up. During this time, you can here what sounds like a voltage leak. A hiss. Then shuts off. What should I check on the power board?

[damen]

That set uses a backlight inverter board for the fluorescent bulbs. Check around the transformers on that board, check the backside for evidence of over heating. Also, look at the board in a darkened room for arcing while its on.

[pac.attack76]

Originally Posted by damen

That set uses a backlight inverter board for the fluorescent bulbs. Check around the transformers on that board, check the backside for evidence of over heating. Also, look at the board in a darkened room for arcing while its on.

Ok, will do. I'll update soon.

[JohnCT]

Originally Posted by pac.attack76

Turns on and display comes up. During this time, you can here what sounds like a voltage leak. A hiss. Then shuts off. What should I check on the power board?

Check carefully the short pink and white wires (typical colors used) from the inverter board into the display. These are thin high voltage wires and sometimes they lay cross each other and will eventually arc a pin hole where they touch.

With the TV off, make sure none of the wires cross each other. If so, separate them and tack down with RTV. If there's a pin hole, a tiny dot of RTV will stop the leak although they usually don't arc if they're just separated.

If that's not it, there's a good chance your problem is inside the display - either a cracked or burned out CCFL tube. When they crack or burn out, the voltage across the dead tube will cause arcing, usually to ground. Once in a while, the end socket at the ends of each CCFL tube will corrode and cause bad connections.

There's also a chance of a burned out inverter transformer. Carefully look at each transformer on the inverter board and see if one looks more cooked than the rest. If so, the trans could just be bad or the CCFL tube it drives could be burned open which causes an overvoltage at the transformer.

John

[pac.attack76]

Ok I'll let you know what I find.

[liammc00]

I have worked on an older Coby tv that used fluorescent backlights. The one I had needed all the caps in PSU changed. So if you get the set up and running I would check the caps in PSU especially if there Capxon branded as those have very high failure rate in Coby TVs.

[pac.attack76]

Originally Posted by liammc00

I have worked on an older Coby tv that used fluorescent backlights. The one I had needed all the caps in PSU changed. So if you get the set up and running I would check the caps in PSU especially if there Capxon branded as those have very high failure rate in Coby TVs.

Yeah this one had the fluorescent backlights and capxon caps. I decided to tear it down and dispose of it.