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hd 4850 problem

Discussion in 'AMD / ATI' started by ste2425, Jan 11, 2013.

  1. OneMoar

    OneMoar

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    let me point out the thing wrong with this and the ways it can go bad
    1. you are assuming your average consumer oven has accurate and STABLE thermal control all but the very expensive ones tend to 'float' the temperature very bad for doing bga work

    2. the rest of the card will FRY at 230c this is why reflow units have very precise and direct heat control either IR or high speed jets of HOTair and metal shields to protect the rest of the card at 230c there is a good chance you will blow the caps off it they will go POP POP POP and then you will be replacing those ( let alone the plastic connectors will melt and turn into soup) Or worse yet you could warp a trace and it could short and set the whole dam machine on fire :eek:
    3.flux is not gonna do shit unless you are removing the chip from the pcb cleaning it and reapplying new solder-balls (yes you can wick some of the heat away and some of it will seep under the chip but all in all you are are doing is risking it coming apart
    ___________
    if you attempt what hellraiser is suggesting there is very high probability that you will kill the card beyond any repair
    I don't know why hellraiser is even suggesting it its a pretty stupid thing todo when the card is already functioning and it could last 6 months it could last 6 years his method is not any better nor will it guarantee a longer lifespan todo that you need a BGA station and you need to completely re ball the Gpu and vram chips
    further more Ill be blunt hellraiser needs to hush because he clearly lacks a real understanding of the forces involved and if you follow his advice you will have a dead gpu on your hands
    450F is WAY TO HOT 350 is pushing it for most gpus thats why I said to start fairly cold because unless you have very tight and LOCALIZED temperature control you WILL break it
    ste2425 says thanks.
  2. eidairaman1

    eidairaman1

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    if you dont want to risk it yourself take it into a PC shop that can do such work. Oven method has a very very low chance of working (reflows can cause shorts then too) plus method that is used is pin pointed to those spots not the entire card. Also a newer card you dont have to worry about crossfire (Both SLI and Crossfire still have issues today). So either upgrade the card to a 6850 at the least which will be cheaper than the whole machine or just wait till you have the cash to get a Shiny new APU machine and grab a 7850 or better.

    Choice is yours but good luck with saving a bunked card that you got ripped off on.
    Zubasa, ste2425 and OneMoar say thanks.
  3. Hellraiser1981 New Member

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    Cool, glad I could help. A couple things to note:
    Make sure the Fan and heat sink are removed (obvious)
    You might want to give the card a bath first (dish soap, warm water, new 1" wide paint brush works well) This will cut down on residue. Also remove any stickers (mineral oil or Avon Skin So Soft works well for this)
    DO A BAKE-OUT (Very important) ~200C 8-24Hr
    The card must be at least 1/4" off of the cookie sheet (or whatever, use aluminum foil)
    Make sure your card is GPU side UP, I've seen some guides saying to have it down, this is just plain wrong, GPU would literally fall off the card at 218C.
    Card must be PERFECTLY level for this.
    Oven might have to be set higher than 450 because 446F=230C which is reflow temp (depends on oven)
    Keep a fan handy for overheat conditions (if over 250C, carefully open the oven door and use fan to blow across oven opening (not directly into oven)
    Back side components should be OK during reflow; surface tension of molten solder should hold them in place. Foil or tape is a bad idea because the tension of tape might offset the component at reflow temp. Larger power supply components (more than 8 pin or QFP might require retention provisions)
    It is OK to cover connectors, jacks, fan connectors, etc... with foil and kapton tape to protect them. They are components designed for the wave soldering process and are not designed to handle 230C reflow temps.
    Good luck and happy gaming!!
  4. OneMoar

    OneMoar

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    ps3 board != gpu
    and I am not trolling you
    you are WRONG and giving bad advice
    lol baking hardware in your bed room I am not even gonna list the ways that can go wrong
    'ghetto' fixing stuff is a good way to break shit
    the gpu is fuctional redoing it hotter and longer is not gonna do shit at this point
    Last edited: Jan 15, 2013
  5. Hellraiser1981 New Member

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    And how many cards/boards have you reflowed? Yes, SnPb is always better, but if someone lacks the technical know-how why suggest reballing? I posted follow-up suggestions for a reason, read those posts before you flame me plz.
  6. Hellraiser1981 New Member

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    Ok enough back and forth, let's put our heads together and come up with a solution. We are both trying to help yes??
  7. OneMoar

    OneMoar

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    the card is working why screw with it
    the only way to permanent method fix it is to have it re-balled using a BGA work rig (500 to 700 dollors USD)
    a 4850 is ancient its not worth the effort to have it reballed the oven got it up and working thats all that matters you are correct no its not gonna last nor should he care if it does or not.
    if the card up and quits again then I would throw it in the nearest trash heap

    done improperly reflowing at home is downright dangerous I have infact had stuff short out because it was run to hot and to long

    if you really think getting it hotter will fix it longer then here is what you need
    a heatgun (something in the 350-500Wat range)
    a very stable and level way to hold the heatgun preferably a clamp or something with adjustable height and X AND Y
    some tin or sheet steel or even roofing flashing (tin foil wont be enough)
    a ceramic mug or small plate cooled to 45-50F
    cut a bit of tin big enough to cover the whole card (this is to help protect the rest of the card)
    next make a template to fix the GPU area and the 4 screw holes and then copy the template onto the tin
    cut a hole in the tin to match the template and leave enough of a lip to the the tin makes contact with the edge of the gpu chip so when you screw it down the tin holds the gpu chip inplace
    put some flux on the entire gpu and then ..
    place the shield on the card and get it barely finger tight
    using a IR probe place the whole thing under the heatgun apply some flux to the and heat the center of the gpu-IHS 228c for 60 seconds ( if you go to long or to hot here you WILL kill it ) very quickly tighten the screws up(do not over tighten them just get them good and snug) the objective is to press the still soft solder-balls back into place if you go to much you will mush then and it will be garbage
    quickly place the cool plate on the IHS of the the gpu for 15 seconds remove and let cool for at least an hour at room temp ( this is done to ensure that the solder SETS
    reassemble and pray ( don't forget to clean the left over flux off )
    congrads you have just done the best re-flow/rework that you can without owning a 500 dollar re-flow oven or a bga station
    the reason for applying a bit of pressure is that if you allow the bga to cool as is it will most likely come apart again due to thermal stress when cooling the objective is to get the bga's incontact without overly smushing them and causing them to run into one mass of solder if you aren't confident in your ablity to get a even torq pattern u may skip the screwing down bit and simply start with the shield snugged down
    Last edited: Jan 15, 2013
  8. Hellraiser1981 New Member

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    I did suggest such a thing but the thread starter did not understand and wanted to go more lo-ball. Hence the oven trick. Agreed if it works now, not to mess with it, but if it fails (and it will) a full reflow would be best. An IR rework station would be excellent to repair the BGA, but ppl don't want to pay 700 or so to save a card worth 100.
    Also I belive you said flux wouldn't do anything, but here you are suggesting it in your post. WTF?? And no you can't attach the HSF and tighten the screws when the BGA is near liquidus temp, you'll turn the underside of the BGA into a giant solder bridge. Also putting a cold piece of metal on the IHS to cool the assembly will cause thermal shock to the die. The chance of cracking the micro solder balls (we are talking about an FCBGA) between the die and the organic substrate will increase exponentially.
    Last edited: Jan 15, 2013
  9. ste2425

    ste2425

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    [​IMG]

    Couldn't help but notice things are/were starting to get a little heated so thought id try to lighten the mood a little. After a bit of thought, and as you guys have mentioned ive decided to go against my motto of 'if it isn't broken, fix it until it is' and leave the card alone. I know it WILL fail. When is unknown if its a month great, if its six amazing.

    I can understand what both of you are saying and concerns about advice etc and whilst i mean no disrespect to anyone who's offered me advice i will take it with a pinch of salt and won't be taking it as gold. Ill find other guides do my own research into the matter and no doubt find other information backing up claims made in this thread. After all were all just blokes sat at computers and i have no idea if the advice is coming from a computer engineer or just another 22 year old like myself who knows very little about the subject.

    As i said im going to leave the card be for now. Just keep it as cool as possible and look after it as well as i can and if im lucky ill get a good few months to play with xfire if not well it was essentially a free card.

    So finally thank you all for the advice and if it comes down to it and i do attempt to re-flow the card ill post my results here
  10. Hellraiser1981 New Member

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    You're absolutely right, I have anger issues so my apologies to OneMoar. We are all trying to help. Yes you should research it on your own. Lots of good reflow/reball videos on youtube, and don't forget to check out whitepapers on bga components from intel and such.
    ste2425 says thanks.
  11. ste2425

    ste2425

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    on a side note im currently running the one card, the baked one actually. My second card is sat on my desk, im awaiting the delivery of a xfire bridge. My question is the opposite to most, can i install both cards plug power into them etc and sort my cable management and all of that fun stuff without the second card being used till i install the bridge? Im fed up of the card sat there taunting me, waiting for my coffee to spill. I know xfire wont work without the bridge unless on specific mobo's which i believe mine not to be but will the card still consume power? Most importantly will it still generate heat and try to compute things?
  12. Hellraiser1981 New Member

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    A perfectly good card just sitting on your desk... gotta be torture lol.
    You could install it and just run it as a secondary card. If you have no 2nd monitor and no xfire bridge, I see no reason to put it back in. It will use some power, not much if you disable it in device manager. Usually the bios will fire up on pcie-0 first anyways. Put it in a static bag and away from your coffee is my suggestion.
    If you do folding or heavy compute then it could be useful as is... Oh and only the really low performance cards from an older gen were able to use pci-e lanes for cross-communication instead of the xfire bridge.

    Funny note: your old motto : if it isn't broken, fix it until it is
    My old sig : if it ain't broke, mod it till it is.
    lol
    Last edited: Jan 17, 2013
  13. ste2425

    ste2425

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    It's because I fancy getting it installed and all looking nice now then it's ready to just pop door of and install bridge. Power consumption isn't really the issue being used and generating heat is. I see it as a clock counting down till it dies so I want as much time using it in crossfire not sat there waiting for the bridge. But if I disable it in device manager windows won't do anything with it.

    And my Moto was given to my about my old fiat. Bought it for £300 and went a bit mad rebuilding suspension brake engine welding etc. spent over £1500 in total. Got parts at trade and fitted all my self so in my defence I got a hell of a lot done for that money :)

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