Hello, I am looking to get some info on an issue I am having with a Sapphire R9 390 8gb. I will try and provide all the info I have gathered and what I believe you need to help diagnose this issue with me. Also, I have another exact same card in good working condition that I reference and can reference further if needed. The card previously worked great for years.
I have checked the card and I didn't find any short circuits. The card powers on, lights and fans work but it is not detected by the motherboard. I have 12v, 5v, 3.2v and .97 on Pex rail. Also have 12v and 3.2v on pcie slot, fuse is good. Resistance from Vcore to ground is 3.5ohms and Vmem to ground 207ohms. All of these readings are documented in the pictures below.
As you can see I have 0v going to Vcore VRM, Memory Controller, and Aux VRM. I am aware that the Aux VRM mosfet is a major weak point on this card and is what I believe to be my issue as well. I am looking for confirmation on that.
I also found a rather large deviation from my good working card to this one. The red box and arrow in the picture is highlighting a ceramic capacitor with odd readings which just happens to be right above the troublesome mosfet. On the good card the capacitor reads 86ohms and 0ohms but the non-working card reads 73ohms and 179ohms. So I assume this capacitor is blown. But can the capacitor be the only culprit for all of my rails not powering on, or is it most likely the mosfet as well. I can provide any and all further readings we may need.
Also, long time lurker here and have learned so much from these forums, so I owe you a big Thank You! Looking forward to being a part of the community.
I have checked the card and I didn't find any short circuits. The card powers on, lights and fans work but it is not detected by the motherboard. I have 12v, 5v, 3.2v and .97 on Pex rail. Also have 12v and 3.2v on pcie slot, fuse is good. Resistance from Vcore to ground is 3.5ohms and Vmem to ground 207ohms. All of these readings are documented in the pictures below.
As you can see I have 0v going to Vcore VRM, Memory Controller, and Aux VRM. I am aware that the Aux VRM mosfet is a major weak point on this card and is what I believe to be my issue as well. I am looking for confirmation on that.
I also found a rather large deviation from my good working card to this one. The red box and arrow in the picture is highlighting a ceramic capacitor with odd readings which just happens to be right above the troublesome mosfet. On the good card the capacitor reads 86ohms and 0ohms but the non-working card reads 73ohms and 179ohms. So I assume this capacitor is blown. But can the capacitor be the only culprit for all of my rails not powering on, or is it most likely the mosfet as well. I can provide any and all further readings we may need.
Also, long time lurker here and have learned so much from these forums, so I owe you a big Thank You! Looking forward to being a part of the community.
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