Feasibility of soldering MBP 17 backlight fuse?

Discussion in 'MacBook Pro' started by DangerousDave2k, May 15, 2018.

  1. DangerousDave2k macrumors member

    Joined:
    Jul 11, 2014
    #1
    I have a 2011 MBP which has lost its screen backlight during a clutch cover change. I probed the ends of the tiny fuse that I gather is the backlight fuse with a multimeter:

    https://imgur.com/a/qMHUs7g

    It is reading no connection, so I think the fuse has blown.

    What are the prospects for me changing this fuse myself, given that I do not have a huge amount of soldering experience? It is very small and surrounded by other components. I have a basic soldering station that looks exactly like this

    https://www.amazon.co.uk/Eagle-Adju...=1526163268&sr=1-6&keywords=48+solder+station

    And I also bought a flux pen, some 22 gauge leaded solder and some desoldering wick. I also have a basic hot air station that I bought years ago and a solder sucker.
     
  2. hughw macrumors member

    hughw

    Joined:
    Jan 15, 2012
    Location:
    Bath/Bristol, UK
    #2
    Personally, I wouldn't touch that with a bargepole. Soldering those tiny SMD parts is a horrendous faff, and not something I'd recommend unless you're experienced and set up for it - having a microscope helps a bunch. If you're set on doing it yourself, have a look at some of the electronics youtubers out there - I think EEVBlog has a piece on SMD soldering.

    The other thing to be aware of is that even though the fuse has gone, the fault may not have cleared, so replacing the fuse may not solve your problem

    If you're lucky, you might have a friend of a friend who does this sort of thing for their job, and might be able to fix it for you, which is what I'd try and do before going and doing this myself

    HTH

    Hugh
     
  3. DangerousDave2k thread starter macrumors member

    Joined:
    Jul 11, 2014
    #3
    No such friends I'm afraid. Unless someone can suggest an alternative, then it seems I either have a Macbook Pro shaped brick or do it myself?
     
  4. Serge88 macrumors member

    Serge88

    Joined:
    May 5, 2008
    #4
    Fuse are rated in amp. Do you know the value of the blown fuse ?
    To know if it's really the problem, you could try connecting another fuse without soldering. Just touch the blown fuse with two wire with a good fuse at the other end.
     
  5. DangerousDave2k thread starter macrumors member

    Joined:
    Jul 11, 2014
    #5
    I was hoping somebody else could tell me which fuse it was. Of if not, which forum I could likely get some help with that information from.
     
  6. kwikdeth macrumors 6502a

    Joined:
    Feb 25, 2003
    Location:
    Tempe, AZ
    #6
    honestly i'd try replacing the cables before i'd bother with the fuse.you say you didnt touch the fuse yet it somehow has blown... chances are you've got a pinched or frayed cable somewhere and replacing the fuse wont do anything, it will just blow out again as soon as you power it up
     
  7. DangerousDave2k thread starter macrumors member

    Joined:
    Jul 11, 2014
    #7
    I think I goofed when I was reassembling the machine, in that I reconnected the battery before I plugged the LCD cable back into the motherboard. I've heard this can cause the fuse to blow (can anyone confirm?)
     
  8. hughw macrumors member

    hughw

    Joined:
    Jan 15, 2012
    Location:
    Bath/Bristol, UK
    #8
    Dave,
    The EEVBlog forum is full of people who do electronics as a hobby and for a job, so it's a good place to start - have a look here: https://www.eevblog.com/forum/repair/

    It appears that the P marking means its a 3A fuse, though you would need to measure the physical size to confirm that

    I'd still recommend finding someone to do the soldering for you, or at least something like a makerspace/hackerspace where you can borrow the proper kit for the job

    HTH

    Hugh
     
  9. Serge88 macrumors member

    Serge88

    Joined:
    May 5, 2008
    #9
    You don't need to remove the blown fuse. You could solder another one on top of it. Like I said before, solder two wire on the blown fuse and test with a good one. Any fuse will do, tiny or regular. Hugh said it's a 3A, go with that.

    Before touching the motherboard, practice soldering wire till you got nice joint.
     
  10. netdudeuk macrumors 6502

    Joined:
    Nov 27, 2012
    #10
    That was going to be my advice. They have a Repair forum here

    http://www.eevblog.com/forum/repair/
     

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