Broken GTX 980M

Discussion in 'Hardware Components and Aftermarket Upgrades' started by Darker01, Nov 11, 2017.

  1. MacGreedy

    MacGreedy Newbie

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    If you look closely you see that a part of the mosfet is still on it. What we would like to know is how to proper remove one because we applied enough heat with the gun but it won’t come loose.
     
  2. Brown bear

    Brown bear Notebook Enthusiast

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    The easiest way to remove the solder is with a soldering iron and a sheath. You can make a braid yourself using old copper wires!

     
  3. Darker01

    Darker01 Notebook Consultant

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    I used hot air rework station. Any generic 858D would do the job. See the set up I use to desolder the MOSFETs on the first page. I replaced ALL of the existing ones because I trust none of them.

    For method, I watch Louis Rossmann's video on replacing the MOSFET on a Mac and followed that as closely as possible. I got some of the Amtech flux which turned out to be pretty good.
     
  4. Ryan Russ

    Ryan Russ Notebook Consultant

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    You may have applied enough heat with a soldering iron but consider also the fact that the mosfet has 9 different pads underneath it and epoxy is a poor conductor. You need hot air and flux to really loosen it, followed with cleaning with a desoldering braid
     
  5. luixyz

    luixyz Notebook Enthusiast

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    May I join this party, I had a burnt GTX980M from a MSI GT72, the left-most 87350D is burnt also taken down the capacitor in the middle "E7 ES" and maybe another small cap & resistor is burnt due to the excess heat behind the 87350D

    The MXM cards power rail is short, I will order the 87350D x8 this week and some extra cap as spare, hopefully to revitalise the poor soul

    Just wondering anyone have the schematic to the GTX980M card for reference?
     
  6. Ryan Russ

    Ryan Russ Notebook Consultant

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    It's fairly difficult to acquire any schematic for any part like the 980m. Besides the PU you ordered, the Cap you're looking for is a 15pf/.15uf 25v vishay cap. The actual code is e7 eX where x is the date code, e7 is the farad value and e is the voltage rating.

    The actual part is difficult to come across but the only one that has made any sense after measurements with my atmega esr meter was that one. 14.5 pf and low esr.
     
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  7. luixyz

    luixyz Notebook Enthusiast

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    Many Thanks, it took me 5+ hours to figure out the model of that cap by studying from different MXM variant of 980M on Google, it was a panasonic 25TQC15MYFB POSCAP 15UF 25V B B2 ESR:100 which is quite hard to get, I think I will desolder the suspicious components first, and check for shorts.

    Besides I will add all 6 87350D to share the power load try to minimise the operating temperature and load distribution.

    [​IMG]
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    [​IMG]
     
    Last edited: Jun 12, 2019
  8. Ryan Russ

    Ryan Russ Notebook Consultant

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    It usually isn't the capacitors on that note. It's more or less always a 87350D that goes bad. Also I personally avoided adding any extra to the cards I've repaired, at most just switched positions. It doesn't necessarily balance load between the fets, as they'll still all be in use at pretty much whatever they can pull from wherever. If anything you'd be adding in heat. In my mind it's better to replace with new parts and make sure they stay cooler than originally, using either shims or thicker pads.

    Occupying all the spots for the 87350d might make each individual part a bit cooler but consider as well that each also has to have its own load, with the capacitors needing to function to support that extra headroom. On top of that, it's very possible that the pathways present in your card are missing components in line with where the new fets would occupy.

    You will definitely need a hot air station, 858D or above, don't use a heat gun, and make sure to use flux when dealing with each spot. Clean them well as well.
     
    Last edited: Jun 12, 2019
  9. Ryan Russ

    Ryan Russ Notebook Consultant

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    So looking at it, the c59 cap is bad, and the 87350d looks to have overheated. The resistor r734 is okay and could be jumpered if needed as if I'm correct it's a 0 ohm resistance, and that cap on the back is difficult to tell, but looks like excess solder.
     
  10. luixyz

    luixyz Notebook Enthusiast

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    Yes thanks, same as my preliminary findings, I have ordered 87350D , the cap C59, when they arrive I shall remove the burnt 87350D and check for shorts again, the cap at the back is kinda explode or got so hot the solder went on the top, most likely dead, if the short doesnt clear after removing the burnt 87350D, I will remove those burnt cap one by one for diagnoses.

    The R734 I need to check again, I think it was ok, just crispy roasted on the surface.

    Also ordered fresh thermal pads and will apply promptly

    With reference to below link (google translate to English) I will follow and add the additional 87350D and the 470uF cap on the left most side.

    http://www.nhl.pl/lofiversion/index.php/t92026.html
     
    Last edited: Jun 12, 2019
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