My neighbor gave me a lcd tv that would power up fine and display the memorex logo sometimes for as long as 5 minutes then go dark. Flashlight shows a picture and it has sound. When the backlights came on you could hear a buzzing coming from the corner of the panel so i suspected bad ccfls. I tore the panel down to get the ccfls out and found they were indeed bad. Two on top and two on bottom. Both the bottoms were completely shot and only one on the top is good. Looked around for a few minutes to price new bulbs and decided to try out some leds. Ordered a 16 foot roll of flexible smd led ribbon that can be cut to fit for 15 bucks. Only need two 16 inch pieces but i can find something to do with the other 13 feet. Anyway, i'll post some pics when i get the leds installed.
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Re: Memorex mlt1921 converting ccfl to led
So you won't be needing the invertersOriginally posted by bigdozer View Post
with the LEDs.
And you can current-limit with a series
resistor, from a DC voltage.
Can we see a spec sheet for your LEDs?
What DC voltage will you drive them with? -
Re: Memorex mlt1921 converting ccfl to led
Yeah no need for the inverters on this one. It has a proview power supply with the inverters built in to it. These led strips operate on 12 volts dc. I looked for a service manual for this tv so i could maybe find my 12 volts on the boards somewhere but no luck. All i could find was the 32" version. I have a box full of 12 volt dc power supplies, so one of them will likely be put into play. One end of the strip has a dc jack and the other end has terminals of some sort.
I dont have a spec sheet for them but a buyer on amazon did some measurements of his.
"I made a few current measurements. 3 LED (minimum strip size) consumes 24 mA. 300 LED (entire 16.4' roll) consumes 1.737 Amps. Each 3 LED section has a 150 Ohm resistor to limit current. A small SLA 12V battery will run a small strip for days/weeks."
If it does come with a spec sheet i'll post it so people can give me some input on what they think. It says they're 6000k and you can get a dimmer for 6 or 7 bucks. It should be a cool project once i get all the stuff in order. I tried to upload some pics of the boards and the bad bulbs last night but no luck. I'm using my 3g wifi hotspot from my samsung phone for the laptop. If the galaxies aren't aligned just right it will not upload a picture. I'll try again later.Comment
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Re: Memorex mlt1921 converting ccfl to led
Doesn't a tv make adjustments to how bright the CCFL is normally using the DIM pin? If so how would that work with an LED light source being on all of the time?Comment
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Re: Memorex mlt1921 converting ccfl to led
I am interested in doing this to a monitor. Can you post details on where you purchased your supplies, and maybe a schematic for driving the LEDS?Comment
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Re: Memorex mlt1921 converting ccfl to led
kits are sold even on Ebay, but thery are not cheap. you can check out Youtube too.Comment
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Re: Memorex mlt1921 converting ccfl to led
Installed the leds today and the tv works. The picture is nice and bright. I tried uploading pictures but i'll have to wait until i get the laptop down to some decent internet. You can faintly see the leds shining on top and bottom in the picture but that was to be expected and it doesn't bother me much. The leds didn't come with a spec sheet so i can't tell you much more about them other than what i've already posted. I got them on amazon.com for 15 bucks.Comment
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Re: Memorex mlt1921 converting ccfl to led
I tried uploading some pics but it wont do it at home. I'll do it tommorow. I've been sidelined for a while and havent really been working on any thing. A dog bit the tip of my finger off and i had to have surgery.
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Re: Memorex mlt1921 converting ccfl to led
Pics as promised. i"ll take some better ones where you can see the leds shining brighter at the top and bottom.Attached FilesComment
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