Question about LCD backlights & inverters

[TechGuy71]

I am wondering if inverters are LCD-specific or if they are somewhat universal. Is there a good resource or way to determine what inverters are compatible with certain LCD's?

Also, what is a good way to determine whether a problem is an LCD backlight vs. the inverter?

I currently have a laptop in that has the normal symptoms of a bad LCD backlight, but it seems for the first moment it comes on it is bright for a split second. I've never seen that. It's usually completely dead.

 

[Troubadour]

Good resource: http://www.laptoprepair101.com/

 

[Lone99star]

If the backlight comes on then goes out it will not be the lamp, it is either the inverter or the power supply, sounds like PS to me but it could be the inverter.

There is a universl inverter you can buy on ebay but you will have to make sure the voltages are the same and probably fit your connectors on it.

I'm sure you have but I have to ask, have you tried an external monitor?

Put a meter on the inverter while powering up and see if there is a voltage loss.

Lone99star

 

[shamrin]

Put a meter on the inverter while powering up and see if there is a voltage loss.

Lone99star

These things put out about 1000v. I really don't know if there's enough amperage to kill you but you might want to use some caution here.

 

[Larry Sabo]

I bought one of these CCFL testers and it works very well. For testing the inverter, you can put the probes of a DVM set on the Hz setting near the inverter and it will display 35KHz or so if it's working. You could also use that DVM to measure the input voltages to the inverter, but finding the pin-outs may be a challenge. There are some on the eBay site that sells the universal inverter.

It was compatible with most Acer,HP,Dell,Compaq,Toshiba,Sony... LCD . You just need to find out from your lcd main board(Vcc, Gnd,On/off and Brightness) 4 pins. Many inverter have more than 4 pins(12pin,10pin,7pin,6pin), they are mostly are several pins are Vcc, and several pins are Gnd.

For example has a 12Pins 4-lamp inverter for Dell 1900FP LCD, Pins Defination is (Pin4-on/off, Pin2-Brightness, Pin10,11,12-Vcc,Pin1,3,4,6,8,9-Gnd)

 

[anonymous Mac Tech]

I currently have a laptop in that has the normal symptoms of a bad LCD backlight, but it seems for the first moment it comes on it is bright for a split second.

More than likely the inverter is bad. But its best to get a tester or what I do is keep a couple busted display panels around that still light. Some like to just pull the ccfl tube out of busted panels for testing but too delicate just having a tube laying around.

 

[TechGuy71]

Thanks everyone for the great info and suggestions. I replaced a broken LCD a couple days ago and hadn't tossed it yet. The screen was broken but the backlight was still oprtational. Anyway I used this to test with. I plugged it into the inverter and powered it up and it lit up just fine. Nothing on the screen cause I didn't plug in the data cable, but it was lit... so that leads me to believe it is in fact the backlight.

Guess I need to stop chucking stuff like that out... it can come in handy!

Thanks again!