Inverter tester using old CFL

[budm]

That is for testing the lamp, for testing the inverter circuits, you need test lamps.
You can use something like this for testing lamps or replace your burnt out inverter.
http://www.ebay.com/itm/Universal-CC...ht_5300wt_1400

[LDSisHere]

I picked up two devices off of Ebay to test CCFL lamps and I find them very handy. I will attach a picture with both of them in it. I like the larger black one better because it will drive larger bulbs and it came with more connectors. Budm's device is good to have around to test the inverter itself but I have found being able to directly test the CCFL's to save a lot of time and trouble. This may especially be true if you are unfortunate enough to have two blown CCFL's at the same time. The black one cost me $8 shipping included and took about two weeks too arrive. This device may not be everyone's cup of tea but I find it extremely useful. Even if I find obviously bad caps I still check the bulbs before doing any work because some monitors are not worth the effort of replacing the CCFL's IMO. It is quite frustrating to recap a power board and still have two seconds to black because of a burnt CCFL.

[Ahakim]

Good idea. Not bad! I have many of them left aside...

[tibimakai]

How could we test LED strips in the panels?

[selldoor]

perhaps one of these?
http://www.lcdparts.net/LEDDriver.aspx

Cant see any on ebay - yet?

[bms operator]

Originally Posted by budm

Do not throw away those broken CFL (14Watts or smaller), you can use them for testing your LCD monitor inverter circuits without buying spare lamps for testing.
You can solder the wires directly to the connectors on the inverter board or you can get the correct connectors but then you have to have more than one type.
I tested it out on my lamp tester board as you can see in the pictures.
I open up the lamp assembly using small hack saw just enough for me to crack it open, just be real careful.
Enjoy!

very informative, I'll do it in the future.Instead of buying spare lamp its good to know broken CFL can be used for testing.

Thank you!

[notallbad]

Decided to hack a Philips 11w Genie Energy Saver bulb for inverter lamp testing, is this one suitable?
Guess I'll soon enough find out!

I noticed that your inverter b/d is slightly different to mine, where your blue and black wires go to the inverter would imply supply and return on the one connecter whereas other inverter b/d's (like the one I'm currently using) have the 'gnd' pin on a 2 pin connector at the bottom of the inverter b/d.

Thanks

[budm]

There is no polarity on the lamp connections to the board, as long as the wires are connected to the two pins of the socket that will be fine. This inverter board is for the TV so the ground return is on the small connector at the bottom right in the pictures, the two pin on the white connectors are for two lamps. If you look at the spec sheet of the panel, it will show how the lamps are arranged inside the panel.

[notallbad]

Thanks, seems I need to hook up one or two more 11w energy bulbs, the house is getting darker and darker as the lights go out and I won't be able to see what I'm doing soon and the wifey be home soon oops, still 2 secs to black!
Arghh dreading the worst now, faulty lamp.

Is this just a test to see the lamps illuminate briefly or should they run continuosly?

[notallbad]

OK, so after having replaced lamp 3 and 4 with energy savers it appears both 3 and 4 lamps are at fault, the backlights and energy savers come on and remain on. But with just 1 energy saver hooked up in place of either lamp 3 or 4 it goes back to half lit screen and 2 secs to black.

Thanks for this great info Budm, its now pinpointed my issue and given me an invaluable test tool for future use. Keep up the great work!

[PohTayToez]

I just used this trick to great success and wanted to say that I came up with an easy way to separate the plastic housing on the base of the bulb. I didn't have a hacksaw handy so I put the lower half of the bulb in a vise and tightened it slowly, crushing the lower housing causing the upper part to pop free. I suppose there might be a chance of shattering the bulb this way, but both the ones I did this too popped free easily without having to apply too much pressure.

[danthompsonz]

I just became a member, looking to repair my GATEWAY hd2200 / SAMSUNG 226BW screen, found a frayed HV wire right at the Silicon boot attached to the CCFL, the Lamp had burst and white stuff all over the back lead me to the trouble. I used this home CFL method and found inverter to be working somewhat. lamps still shut off and back on now in about 30 sec intervals, instead of 2sec to black. wonder if some component has also shorted on the inverter board.
All caps have been replaced, whole board re-soldered, and computer was attached to avoid standby mode, but still DOES go to standby, lamps off and returns back on by it self, lamps back on. any thoughts?? thanks Dan

[Phoenix83]

Good idea, nothing complicated and yet it works.
Tomorrow I'll try it with 14W conventional fluorescent bulb.

[HAHOMETP]

Originally Posted by LDSisHere

I picked up two devices off of Ebay to test CCFL lamps and I find them very handy. I will attach a picture with both of them in it. I like the larger black one better because it will drive larger bulbs and it came with more connectors. Budm's device is good to have around to test the inverter itself but I have found being able to directly test the CCFL's to save a lot of time and trouble. This may especially be true if you are unfortunate enough to have two blown CCFL's at the same time. The black one cost me $8 shipping included and took about two weeks too arrive. This device may not be everyone's cup of tea but I find it extremely useful. Even if I find obviously bad caps I still check the bulbs before doing any work because some monitors are not worth the effort of replacing the CCFL's IMO. It is quite frustrating to recap a power board and still have two seconds to black because of a burnt CCFL.

LDSisHere,

thank you for confirming my choice of the black tester over the blue one. Just ordered it from HK.

In the 4th picture all 18 CCFLs appear to be dark in the middle. Do you know why this is happening?

[LDSisHere]

The tester is made to drive one or two CCFL bulbs at a time. The 18 are part of a 32in TV where all the bulbs were wired in parallel. The center not being lit is not important as it is due to lack of power. The important thing is that they are uniform and all lit, if one was bad it would stand out. I was just wanting to show what it could do when pushed beyond it's design limits. I would also not do this for very long as it could damage the driver.

[HAHOMETP]

The reason I asked is I am seeing exactly the same in my Dell 2408WFPb:
http://www.badcaps.net/forum/showpos...7&postcount=19

The curved portions of the U-shaped lamps in the left side of my monitor are equidistant from their pins and they sometimes remain dark whereas the right side of the monitor where their straight ends are located ignites just fine. The fact that all 7 of them are doing this simultaneously leads me to believe that the problem might lay upstream. Perhaps the CCLFs are not getting enough power? If yes, then what common element might be responsible for this?

[budm]

Not enough voltage to drive the lamp is what I have seen when lamps are not fully lit.

[aortiz]

good afternoon bud,can i use just 1 lamp,or i have to to have all the lamps conneted to the inverter board,to find out if the inverter its working or not? my dell monitor looks like it has all bad lamps,6 of them.

[HAHOMETP]

Budm wrote in another thread:

Originally Posted by budm

Thanks for the follow up. So what kind of 5W CFL lamp did you use? T5 type?

Yes, I scavenged a 4W T5 bulb from an old Coleman Powermate. I should've gotten 6 more of those along with 7 pairs of alligator clips. The monitor that I was troubleshooting had problems in two inverters at the same time. That's why this single bulb when connected to them one by one would still result in the two seconds to black.

Since we are on this subject.

A while ago I took apart a non-working fluorescent bulb with a spiral tube like in the OP. The bulb was merely a week old and the tube looked brand new w/o any dark spots, so naturally I suspected the electronics. The circuit was comprised of several discreet components and I tested every one that had a p-n junction - they all checked out fine. Next I took apart an identical brand new bulb - fortunately this particular type had the easy to open snap-in cases. I swapped out the tubes with the electronics. After that they both lit up fine.

In this particular bulb (picked up on HD sale: $2.97 per pack of 4, Soft White 2,700K) the spiral tube pins are simply inserted into the two pre-tinned eyelets in the PCB. The pins on this tube were dark of oxidation. My guess is the pins gradually lost contact with the soft tin in the eyelets and the bulb stopped working. I scraped the pins with a knife, reinserted the tube into the circuit and the bulb fired right up. In the hindsight I should've taken apart 3 or 4 dead ones that I had tossed into trash a few weeks ago. I bet they were fine as well.

Yesterday I finally received that $8 CCFL tester from China. Below is a picture of the 4W T5 bulb connected to this tester in front of the newly repaired Dell monitor.

[HAHOMETP]

A loosely related follow-up.

This $8 CCFL tester from China and a $10 Milwaukee Non-Contact Voltage Detector (2200-20) proved to be rather useful in troubleshooting the intermittent lighting issue in the lightbox for commercial photography that I've built a while ago. Turned out that all 8 fluorescent tubes are still good but 2 out of 8 channels in the IceCap ballasts are dead.