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Thread: Buying LED backlight upgrade?

  1. #1
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    Buying LED backlight upgrade?

    Hi all,

    Basically the backlight on my K301 has died, and while disassembling it and trying to figure out why it died, I promptly broke the CCFL tubes as well.

    So I need to get it replaced.

    But if I am to replace it, I might as well go for an LED option instead of CCFL for better colours (can get rid of the inverter as well). So where can I possibly buy an LED backlight panel?

    Thanks.

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  3. #3
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    I would if I was in the US, unfortunately with the shipping + taxes the $200 will become pretty much the price of a brand new one here...

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    Hi,

    What does everyone think about using a number of these as backlight? 18 of them will fit a 7" screen perfectly I think, in total it will be around 600nit.
    http://www.ultraleds.co.uk/strip-cha...0v-p-1557.html

    Thanks.

  5. #5
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    Being a fellow k301 owner, I am very interested in your results. How long did you backlight last before it died? Did it just one day burn out or was it a gradual reducing in brightness? If it just suddenly died, I am suspecting that it was your inverter which gave out, so you might want to test that. I think alot of aftermarket screens (like our k301, or flip out units) might be using cheap tubes. I read the instruction manual for some newer model Alpine flip screen and the backlight was only rated for 10k hours, whereas newer ccfl tubes are rated for over 50k hours.

    Also, how did you manage to get access to the backlight itself? When I took apart the screen, I had to manually pry open the lcd casing. Once in, the backlight assembly was held in the metal backing with some black plastic tabs, and I am unsure how to get the backlight assembly off (didnt want to use too much force) to gain access to the ccfl tube.

    There does not seem to be much room in the k301 backlight assembly for LEDs. How were you planning on putting the LED's in the place of the ccfl tube? I dont think there exists a LED tube that you can simply slide in. You would need to arrange each led lamp manually. In regards to the link above, even those LEDs seem a bit big to fit. You should take measurements first so that we know how much room you have to work with. Also keep in mind that you will have to desolder the tiny LEDs from the solder board and figure out a way to assemble them. Unfortunately, I would have to say that simply replacing the ccfl tube is much more feasible than going with LED due to the risks involved. The only benefit that I see to using LEDs is that they wont get dim in the cold. But if you do successfully manage to get a LED backlight working, please post pics.

    Good luck.

  6. #6
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    Quote Originally Posted by nobb View Post
    Being a fellow k301 owner, I am very interested in your results. How long did you backlight last before it died? Did it just one day burn out or was it a gradual reducing in brightness? If it just suddenly died, I am suspecting that it was your inverter which gave out, so you might want to test that. I think alot of aftermarket screens (like our k301, or flip out units) might be using cheap tubes. I read the instruction manual for some newer model Alpine flip screen and the backlight was only rated for 10k hours, whereas newer ccfl tubes are rated for over 50k hours.
    It lasted about a year, then suddenly died. I know it is highly likely to be the invertor, but the invertor is part of the LCD circuit And I've never been happy with its lack of sunlight readability anyway, so I am looking at better backlights.

    Quote Originally Posted by nobb View Post
    Also, how did you manage to get access to the backlight itself? When I took apart the screen, I had to manually pry open the lcd casing. Once in, the backlight assembly was held in the metal backing with some black plastic tabs, and I am unsure how to get the backlight assembly off (didnt want to use too much force) to gain access to the ccfl tube.
    The black plastic tabs simply prise up, they are not even glued down - they are there to hold the two wires and the light-guide in place only. And oh yea I broke the tubes as the unit slipped out of my hands...

    Quote Originally Posted by nobb View Post
    There does not seem to be much room in the k301 backlight assembly for LEDs. How were you planning on putting the LED's in the place of the ccfl tube? I dont think there exists a LED tube that you can simply slide in. You would need to arrange each led lamp manually. In regards to the link above, even those LEDs seem a bit big to fit. You should take measurements first so that we know how much room you have to work with. Also keep in mind that you will have to desolder the tiny LEDs from the solder board and figure out a way to assemble them. Unfortunately, I would have to say that simply replacing the ccfl tube is much more feasible than going with LED due to the risks involved. The only benefit that I see to using LEDs is that they wont get dim in the cold. But if you do successfully manage to get a LED backlight working, please post pics.
    The light guide is quite thick, and there is actually a little bit of space between the sheets and the LCD itself, so an array of SMD LEDs that are less than 3mm thick in total might be ok.

    Failing that, an EL sheet might be ok? I don't know.

    However, there won't be any pics to post... because about an hour ago the motorising mechanism died When I press the eject button, it just gives me three beeps...

    I don't know how to fix it (yet), and I am not sure if I can get rid of the mechanism and just use the LCD panel, if I can't find a solution then this K301 might well be a write-off...

  7. #7
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    Oh that sucks. You should probably try to fix the motorized mechanism first. Is it really cold by any chance? When its below -5C, the screen will give 3 beeps and fail to open until its warm. I actually hacked the k301 to bypass the temperature sensor (search my post "bypass temperature sensor") by replacing the thermistor with a 10k ohm resistor. I suppose just to be sure, you could put a mutimeter across the thermistor terminals to make sure the resistance is 12kohm or lower (10k should be room temp). Hope your screen works out in the end.

  8. #8
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    Hi,

    When the backlight died, it was really cold.
    When the motorised mechanism died, it wasn't - it was on my desk.

    But from your descriptions, it sounds like I have a busted thermistor Which would be an easy fix.

    Thanks for the tip dude!

  9. #9
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    hmm...I wonder why the inverter would die when its cold. I sure hope that doesnt happen to my unit when its -40C this winter.

    When I take apart my k301, I usually apply power to the screen, open the screen, and when the screen is extended at a horizontal position (right before it flips out), I cut power and so the screen is stuck that way and I have access to it. Since your k301 fails to open, is there another method you can use to force the screen out and gain access to its internals? If you have been somehow forcing the screen to open, maybe that is how your mechanism died in the first place?

    I also forgot to mention that I suspect the screen uses a resistive type of device (dont know where it is though...probably connected to a gear somewhere) to determine the extend of extension/screen flip position. I know one of the lilliput motorized models use this. You could also try to check whether this device "slipped" and is giving a false reading. Although I am not familiar with these devices, so I dont know how you would determine that.

  10. #10
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    Found your thread and many thanks, it certainly will help.

    However! I've got one problem now... my display is in "retracted" position when it died, so I can't check the thermistors until it slides out... chicken and egg you see!

    Do you know of any way I can force it to open (like, by shorting two particular points)? No I've not been forcing it to open.

    I don't think the weather killed my backlight, I think it is because I ran it from unregulated +12v, as I wanted auto-on/off.

    Thanks.

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