To know a mosfet values in a GTX 760 - Page 1
Forum section: electronics / beginners

author: deadmanwalking
author_rank: Newbie
timestamp: September 19, 2018, 02:19:08 am
content: I have an Asus GTX 760 Direct CU II graphics card that worked perfectly until I removed it from the PC to make it maintenance and to clean the accumulated dust, aply fresh thermal paste and change thermal pads for new ones. When I installed it again on the PC, the GPU turned on the power LEDs and turned both fans, but there was no signal to the monitor. At the time I assumed that I had zaped it with an electrostatic discharge and fried some component or even the GPU chip.I was disappointed and for a while I left it aside, since I had other spare graphics cards so I do not pay much attention to it.Now that I started to remove all the PC components that I had accumulated all this years I checked it again closelly, and it turns out that I do not know how, it received a blow that broke one mosfet, which could be the real problem. Seeing all the mosfet that are around and in similar arrangements inside the card I deduce that it is an S72 3 2, when I google that part number I do not find anything concrete, but if I search only S72 I get as a result a mosfet SOT-23 2N7002 , but there are several mosfet with that size format and name with different values ​​according to the technical sheets of various manufacturers.I have looked for the diagram or something that gives me a clue of the correct values ​​of the mosfet, but with no luck, in the PC components world there are zero diagrams, I suppose that almost always (with the exception of the iMac) it is more practical and economic to change a card than repair it.After all this history,how do I find out the manufacturer of this mosfet to see the technical sheet?already googled it all day long...Or, failing that,how do I measure the values ​​of the mosfet around to buy an equal one, even if it is from another manufacturer?It could be that this 3 and that 2 correspond to the SOT-23, but in some technical sheets of some manufacturers the 2 extra numbers correspond to the year and month of manufacture, or also to some special feature of the chip ...What interests me is to find some mosfets of the same manufacturer or in their absence some equivalent of good quality.The most common 2N7002 in ebay are 60V 290mA, 60V 310mA and 60V 115mA in mercadolibre.com.mx the only one in existence is 60V 120mA (I had bought with 2 other sellers, but they canceled the sale for lack of stock, a very comon practice in that selling webpage).I want to clarify that I lack of the knowlege beyond replace a bulked capacitor or solder together a project kit, my only tools are a $6 mistery brand soldering iron and a $14 el cheapo chinese multimeterThank you very much in advance for the help

author: McBryce
author_rank: Super Contributor
timestamp: September 19, 2018, 09:02:19 am
content: I'd try any 2N7002, which are cheap and available on ebay from sellers all over the world:https://www.ebay.com/itm/100pcs-NXP-2N7002-Transistor-N-Channel-MOSFET-60V-300mA-SOT-23-Buy2Get1FREE-NEW/142180583749The exact current rating is most likely unimportant (look at the size of the PCB traces going to the component). I very much doubt that the MOSFET is driving anything substantial.McBryce.

author: deadmanwalking
author_rank: Newbie
timestamp: September 19, 2018, 03:33:03 pm
content: Thanks for your answer McBryceQuote from: McBryce on September 19, 2018, 09:02:19 amThey're cheap, but USD$40 for shipment to Mexico...Quote from: McBryce on September 19, 2018, 09:02:19 amAs I don't know much on electronics always replace components with same part number or equivalent of a good reputation brand, it worked for me until now that I can't detemine the mosfet specs, I'm afraid of burning a good video card that only need a USD$0.1 component, that's why I'm asking to the people more into electronics and it's secretsI already purchased the last 4 aviable mosfets on mercadolibre.com.mx (and aparently on all Mexico) for USD$4 plus USD$5 for shiping, they're 60V 120mA but I'll be more confident to replace it if I know they're at least close the the original specs, and if the video card don't work, I can discard the mosfet as the cause of the failure.

author: deadmanwalking
author_rank: Newbie
timestamp: September 20, 2018, 02:07:37 am
content: Well, in the end I solved the "problem", which apparently was not so much a problem ...Today DHL delivered the mosfets 2n7002 that I bought in mercadolibre and by McBryce's advice I decided to risk making micro soldering caveman style the 30V 120mA mosfet to the video card, which I do not know if it is close to the original values ​​but it worked perfectly (right now I have the GTX 760 connected to the monitor and use it to write this message).To be honest, seeing the video card pictures enlarged I do not like how the solder is, but if you do not use a microscope and you do not know what you are looking for, I can bet you can not tell which is the new componentI already stressed the GPU with an overclock and the heaven of unigine test for half an hour with very good results and there are no artifacts, no lines, nothing strange in the monitor, the temperature under load stabilized at 80 ° C, which is normal for the GTX 760.All this leaves me a little learning about the mosfets, their values ​​and interpreting their technical sheets, thank you very much for the contribution McBryce

author: McBryce
author_rank: Super Contributor
timestamp: September 20, 2018, 07:38:17 am
content: No problem and congratulations on getting it working again. It's highly unlikely that the MOSFET is handling any high frequency data pushing/picture creation. It's more likely that it's just enabling/disabling some function on the board (Fan control or similar), but still enough that the card won't start up without it doing it's job. Artifacts etc come from the RAM/CPU being overclocked/getting hot/faulty etc. So your repair will most likely be robust enough to get many months/years of gaming from the card without an issue.McBryce.