# Help on 5850 (broken fet) i think...



## lifeforce (Jun 2, 2011)

Hi.I have this problem 
http://imageshack.us/photo/my-images/24/p5230191.jpg/
http://imageshack.us/photo/my-images/827/p5230192.jpg/
its broken and i cant recognize what fet to buy,can someone help me with this?i will post a greek store (cause i am from greece) and can someone link to me what to buy from all this fet?
http://www.acdcshop.gr/transistorfet-c-54_74.html  (money is no object i just want the best)
sorry for my awful english  and thx in advance.


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## brandonwh64 (Jun 2, 2011)

It could possibly be soldered back on if you took your time


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## lifeforce (Jun 2, 2011)

yes i know i just want to have a backup just in case...


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## OneMoar (Jun 4, 2011)

can't read the numbers to small post the text on the top of the mofset
thats what it looks like some kind of mofset or part of the vrm


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## cadaveca (Jun 4, 2011)

gonna take more work than just getting a new component...traces have been pulled right off the board.


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## OneMoar (Jun 4, 2011)

cadaveca said:


> gonna take more work than just getting a new component...traces have been pulled right off the board.



mmm I zoomed I didn't see any trace damage looks like the part of it is still stuck to the board 
then again the picture is not exactly clear 
if there is trace damage the card is junk


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## cadaveca (Jun 4, 2011)

I see copper attached to all of the component pads...equals trace pulled.


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## OneMoar (Jun 4, 2011)

if the trace has been lifted but not broken might be-able to epoxy it back down and then solder a new mofset in 
I have repaired traces with epoxy before just make sure you use non corrosive non conducting epoxy ( most 5 min quick set 2 part will work  )


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## OneMoar (Jun 4, 2011)

another getto trace repair trick is to use conductive paint 
silver or gold conductive paint would be best but copper/carbon based paint might work for this


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## micropage7 (Jun 4, 2011)

yeah using epoxy and glue it may solve your problems. but theres a chance of failure since its small stuff


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## lifeforce (Jun 4, 2011)

thx alot for the help,the mosfet even attached to the card is not working,it has a number on it 70,3,but i think its going for trash...


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## OneMoar (Jun 4, 2011)

i believe this is the component 
http://www.arrow.com/1/1/38647-transistor-mosfet-n-ch-60v-0-31a-3-pin-sc-70-t-r.html


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## lifeforce (Jun 4, 2011)

Ordering it nowthx alot


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## OneMoar (Jun 4, 2011)

lifeforce said:


> Ordering it nowthx alot



just to be clear  I am not 100% sure but thats the closest I could find
if the number you listed is correct and I am looking at the circuity right it looks to be a sc-70-3 power mofset but there are several variation's of that mofset with different ratings
heres one with a higher rating 
http://www.arrow.com/1/1/1014107-transistor-mosfet-n-ch-30v-0-87a-3-pin-sc-70-t-r.html
the problem is I can't tell you if its a transistor-mofset(one that amplify power)  or a power mofset(one that simply regulates)  with 100% certainty put the wrong one in there are you will burn something up


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## lifeforce (Jun 4, 2011)

i think there is a second exact same on the graphic card, i will post some pictures.


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## lifeforce (Jun 5, 2011)

http://imageshack.us/photo/my-images/832/newma.jpg/

these two got the same number on them,here is another picture it says 70,3 and a 5


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## OneMoar (Jun 5, 2011)

after staring at the picture 90% sure its a power mofset but without looking at the card and testing with a multimeter I can't be 100%


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## lifeforce (Jun 5, 2011)

so should i order the one you said on previous post?


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## OneMoar (Jun 5, 2011)

you can try putting this one on there 
http://www.arrow.com/1/1/1014107-transistor-mosfet-n-ch-30v-0-87a-3-pin-sc-70-t-r.html
I have No idea if thats the correct type don't ragge if it goes up in smoke >_>


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## lifeforce (Jun 5, 2011)

nah i wont and thx for the help.


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## lifeforce (Jun 5, 2011)

i wish i knew how to use a multimeter hehe..


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## brandonwh64 (Jun 5, 2011)

lifeforce said:


> i wish i knew how to use a multimeter hehe..



omg......


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## OneMoar (Jun 5, 2011)

multimeter won't really help you w1zzard is the one we need in this thread he knows a lot more about the hardware then I do


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## OneMoar (Jun 5, 2011)

Probly should have asked this earlier is it it still under warranty


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## lifeforce (Jun 5, 2011)

no its not under warranty,thats why i am asking


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## lifeforce (Jun 5, 2011)

i'll try to pm w1zzard then maybe he can help me


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## lifeforce (Jun 6, 2011)

bump no response by him and its normal cause he is admin of this forum,so i'll just try the one you linked to me and lets hope it works,thanks again


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## SaiZo (Jun 6, 2011)

If you try to solder it - use something to "secure" it on place, does not need to be glue under it. Just so it does not move. Also make sure that the tip of the soldering iron is small enough.

I had same issue with a remote control for my RC heli, same type of component. It was like surgery to get it back on. I actually used a dremel on the tip of the soldering iron just to get it to be small enough to solder it on. No hardware shops were open on a sunday, so it was difficult to get a new tip for it.

You can also secure the pcb with something like a "helping hand" so that does not move either.

Good luck, hope you manage to get it working again.


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## lifeforce (Jun 6, 2011)

yeah will do thx for the tips


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## lifeforce (Jun 8, 2011)

nope its not working,fan is spinning but nothing more, the good thing is that i found a palit gt220(a friend of mine has it and not using it) and it has the same mosfet but it reads 70,3 and a rotated 7 on it(on mine its 5) here is a closeup,anyone know if its making a big difference?
http://imageshack.us/photo/my-images/11/backfull14.jpg/


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## lifeforce (Jun 8, 2011)

np i just found that the number 7 or 5 is the date code marking(year or month) so its nothing.Will try it today!


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## Hellraiser1981 (Jun 14, 2011)

looks like an output mosfet for the vref circuit.  Probably driven by a nearby ic.  use a dmm to test the fet, all terminals should read infinity.  if source and drain are shorted, that would explain why it melted off the board.  also find out if it is hi or low side mosfet.  If it's high side (+v) then gpu is probably popped.  These usually don't fail by themself, i would suspect a short somewhere else (metal shavings from screws??)


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