Elitebook 8530W Brightness control problem

Discussion in 'HP' started by Danishblunt, Dec 22, 2018.

  1. Danishblunt

    Danishblunt Guest

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    So I got a used 8530W and it has the issue where the brightness control cannot be controlled, it's always on low brightness, regardless of what seting someone puts.

    @t456 maybe you know somethng? :D
     
  2. t456

    t456 1977-09-05, 12:56:00 UTC Moderator

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    If it's an original panel then a clean install should fix things (or try Linux first). But if it's a replacement then it may have a pwm range mis-match issue, the fourth option in this post. Could try holding brightness-down for a while and if you're lucky you may actually get full brightness when requesting the dimmest option in its range.

    What panel is it? Knowing that it's pretty easy to make a permanent fix, though you'll have an 'always 100%' panel instead.

    It does have a working backlight, yes? So no need for a flashlight to spot anything at all on the screen?
     
  3. Danishblunt

    Danishblunt Guest

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    yes it's simply on the dimmest setting.
    Panel and GPU are both original.

    Its the 1920x1200 version. Don't know the model, can provide it in around 12 hours.

    EDIT: LG Phillips LP154WU1-TLC2
     
    Last edited by a moderator: Dec 26, 2018
  4. t456

    t456 1977-09-05, 12:56:00 UTC Moderator

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    Ah, that's a rather old CCFL panel. It's using direct DC-variable brightness control; lower input voltage to the inverter results in less current delivered to the backlight tube.

    So either the motherboard's power supply to the inverter is defective or, far more likely, the inverter or the tube itself is in need of replacement. An inverter is pretty cheap, but you could also tackle both lcd-side options at once by replacing the CCFL with a LED backlight:
    335mm Backlight LED Strip Kit Update 15.4 Inch LCD CCFL Screen

    We just need to know what type of connector the current inverter uses, it's 2-pin or 4-pin. With that you can order the correct ~$3 kit and swap both the tube and the inverter. Removing the old tube intact is pretty tricky due to its fragility (it's glass, after all). Doesn't really matter if you're going to replace it anyway, but all the same it's a good idea to watch a youtube for the proper sequence of the disassembly. Main thing to remember is that you need to remove the metal bezel that covers the panel's edges before you can remove the tube and, very important, not to remove the lcd from its backlight frame (otherwise dirt may get trapped in between).
     
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  5. Danishblunt

    Danishblunt Guest

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    Is there any panel I could swap?

    Was thinking about replacing it since color coverage is meh anyways.
     
  6. t456

    t456 1977-09-05, 12:56:00 UTC Moderator

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    No reviews, but these should be quite an improvement:
    They're all dual CCFL panels though and the WU1 is only a single tube design (there's no better panels with single CCFLs). Input for the inverter is 2-pin, which is identical to the WU1 and that also means it's a voltage-controlled backlight; a 4-20 pin would mean you'd loose brightness control, plus it'd have required cable soldering.

    You do need that 2x 2-pin out inverter then, even if the current one wasn't already defective. Most of these panels will be sold without the inverter, unfortunately. An adapter kit would do fine, but is a bit more work. For either the kit or a regular inverter you still need to be sure as to which type it's using, so first step is to remove the panel and have a look.
     
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  7. Danishblunt

    Danishblunt Guest

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    Thanks a lot! I could do some soldering etc. no problem :)
     
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