Howto: Make a CCFL tester

[Th3_uN1Qu3]

Just a quick howto here.

Step 1. Find very cheap (or free) monitor with cracked panel. It could of course be any other failure with a working backlight, but monitors with bad panels are first to be tossed away usually.

Step 2. Find pin labeled BL on the connector going from the power supply to the logic board. If it isn't labeled, probe around for a pin that gives close to zero volts when the monitor is OFF, and close to 3.3v when it is ON.

Step 3. Wire the BL pin to the 3.3v rail of the power supply. You now have a PS that will run the inverter without a logic board connected. Confirm this by disconnecting the logic board.

Step 4. Remove PS from monitor with cracked panel. You now have a standalone CCFL tester. That's all.

[DMCrimson]

Re: Howto: Make a CCFL tester

This should be added to the FAQ - I just happen to have a FS 17" tft with smashed screen Need to probe around to find BL and 3.3V, then find a suitable housing for that board.

[budm]

Re: Howto: Make a CCFL tester

The panel for mounting the boards came from inside the LCD panel. I save them for making a lot of projects.

[Th3_uN1Qu3]

Re: Howto: Make a CCFL tester

As a bonus i'll make a tutorial on how to dim the CCFLs as well so you can test for failing lamps (aged lamps flicker when the backlight is dimmed low). I use a couple CCFLs scavenged from a 15" with cracked screen to light my workbench, so i make full use of the dimming feature.

[budm]

Re: Howto: Make a CCFL tester

I used the Inverter board that has DC control for dimming function, I use the pot to vary the input voltage to the DIM line 0V = OFF, 5V = MAX brightness. I am planing to make portable CCFL lantern with dimming funtion running off 12V batteries, but I may end up using LED instead.

[DMCrimson]

Re: Howto: Make a CCFL tester

I'll test that PS later today and see if it works - and if it does, I'll box it up. Is the hot wire marked somehow on CCFL's?

[Th3_uN1Qu3]

Re: Howto: Make a CCFL tester

The hot wire is the thicker wire.

[budm]

Re: Howto: Make a CCFL tester

Actually, there is no hot side or cold side of the CCFL since it is just a lamp without any polarity, they have to use smaller wire in one end because the wire has to fit inside the LCD assmbly and run all the way back to the connector which on the other side of the panel, when you buy raw lamp and solder the wire back on youself you do not have to woory about which end of the lamp go to which wire, same thing when you change the SHOP LAMP, you van put tyhe lamp in either way.

[gerg]

Re: Howto: Make a CCFL tester

I use a cold cathode light for making your computer pretty with pins that will connect to the light you are testing and hit the switch to turn it on from a power supply not connect to a computer. ghetto but it's functional