Repairing LCD TV - Westinghouse LTV-32W3

Is it really 800V? If so what does my laptop use to step the voltage up to that level?

There are low voltage fluorescents out there. I know, I have one in my toolkit and it runs on 4.5V.

Fluorescents are discharge lamps, the smallest in the world require somewhere around 50V to draw an arc through the low pressure argon/mercury fill. Cold cathode lamps used in LCD monitors require a higher voltage, usually 500-1500V run with a 2-4KV ignition pulse. Any fluorescent application with a low voltage power source uses an electronic inverter to provide the required voltage and regulate lamp power.

Voltage converters.

It uses 4.5 volts input to the voltage converter. A fluorescent requires enough voltage to create an arc in the mercury vapor.

Alan

On Sun, 03 Feb 2008 18:11:23 GMT, snipped-for-privacy@hotmail.com put finger to keyboard and composed:

I have no experience with LCD TVS (only LCD monitors), but I'm wondering what is inside the tuner/IF can that warrants a heatsink for this module? And why do the other chips require such massive heatsinks when I see nothing of that kind in LCD monitors or digital STBs?

- Franc Zabkar

Thanks for all replies. This week I got very thin fan that can be attached to a metal sheet that covers the circuit board that I think is overheated. Here is PowerPoint (3mb) as it looks like on my TV:

Thanks,

Zalek

Hi, From the board find a source for 5V or 12V DC depending on fan voltage. You can include an in-line pico fuse if you wish. Thought about drilling whole bunch of holes at the bottom/top of cover to increase the air flow?

Yes - I thought about drilling more holes. Here are the fan specs:

# Specifications: Model: EC4007M05CA, # Voltage VDC: 5; # Current AMP: 0.15, # Input Watts: 0.75, # Fan Speed: 4500, # AirFlow CFM: 4.81, # Pressure MMH2O: 2.38, # Noise dBA:

appeared:

Unlikely to use too much power. If you look at that plastic connector between boards, there's probably power available right there. If you cut to 1/2" pieces of stiff paper clip, you can likely force each down into the +12v and ground lines that are likely located there. Then bend the protruding ends to match the pin spacing on the fan connector. Be sure to observe polarity.

All that said, I'd closely examine the convective air currents naturally occurring in the set when in operation; then locate the fan to enhance them. That will likely put your fan much higher up on the panel than the site you've chosen. Otherwise, you could actually impede the airflow, rather than increase it. Convection will always induce air currents. If you put your fan in opposition to them, stagnation occurs.

jak

Hi, I don't think so. It draws only 150mA. You can slow the fan speed down with voltage drop resistor in series as well. Or if you install variable resistor you can set the fan at a speed you need. 1/4 or 1/2 Watt resistor will do.

It'll take a whole 3/4W at 5V. That isn't much.