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Once again it was just one pin on 81161 that caused this. It wasn't soldered properly, because I really should use solder in paste or at least clean the old solder and not just reflow the solder that was there. I'm still learning hot air soldering. But anyway after making sure that every pin is...

I’ve been using 858D hot air station.

From what I found, 81161 is decreasing resistance of this resistor (without it resistance is 10K, just like after desoldering this resistor from the board). But on this phase even with a 81161 from the other phase it still has that 8.7K resistance.

I did that and those resistances are the same, 10K for each.

Yes, it’s the same on every phase.

There is continuity to the high side gate pin on the mosfet and 1.6 ohms to the high side gate drive.

It is actually, to every output choke. Same for the other resistors. There’s continuity there. And yes exactly. On the other phases there is 7.7K -7.8K but on the suspect phase there is 8.7K.

It’s 1.8 ohms. There might be something in between actually when I think about it now, don’t know what though.

Not exactly, resistance on the ground leg is near zero. But something happens when measuring through this resistor and resistance is higher than the corresponding resistors on the other phases. But resistor itself is good.

What seems to be confirming that is that on the faulty phase there is a higher (about 1K higher) Gate to Ground resistance on my card. From what I can see this resistance is mostly depending on a resistor between high side gate driver output and ground (R510 on the faulty phase). Resistor itself...

I think that it might be just a PCB that goes bad after waranty time due to insufficient cooling of VRM. I literally tried swapping everything on this phase and result is always the same. I guess this card just can’t be fixed.

Yes, I'm using hot air.

So it was just a poorly soldered pin that caused that. I did manage to run it after fixing that and replacing the inductor and also mosfet and voltages and resistances on the faulty phase were the same as the other phases. But it died again anyway, even faster within few seconds of load. This...

Well, that was exciting. So I swapped NCP81161 and the bootstrap cap and after that forward direction resistance was 13.5K so close enough to that 14K of a good phase. Then I connected my multimeter probes to measure bootstrap pin to ground voltage and I turned on the computer. Multimeter showed...

It might be possible that the previous bootstrap capacitor was indeed faulty and did something to the changed NCP81161 on the faulty phase. Therefore I'm getting those weird values. Just guessing. I can swap the NCP81161 again, but I don't know whether it's even worth trying that.

OK, I did the measurements and here's what I've found: Forward direction Good phases - ~14.5K Bad phase - 54.1K Reverse direction Good phases - ~2.89M Bad phase - 2.95M

Well, I didn’t thinked of that. Reversing the probes helped :P There’s 1371 on the faulty phase and 257 on the good phase.

Yes.

I get open circuit between the bootstrap pin and the 12V input - both on good phase and the bad phase There are 0 hm bootstrap resistors between the pin and the capacitor - my multimeter is showing around 1 ohm there on the good and bad phase.

Exactly. To be precise I'm not measuring from the leg of the NCP81161 because it's too small. I measure it from the leg of the bootstrap capacitor that is directly connected to that pin.

There's definitely something wrong with the bootstrap circuit on this phase when you compare these voltages to the other phases. On the phase below the faulty one, it's ~12.9v on idle and ~13v under load. That's a massive difference, but what is causing this? Also one interesting thing is that...

I replaced mosfet and fuse again and I also replaced the bootstrap capacitor. As always, card is working now, but the question is for how long? Additionally, I checked the voltage from bootstrap pin to ground this time as mentioned earlier in this discussion. I found that when card is on idle...

I didn't, but I can replace it and see if that will help.

Well, it died again. It worked fine for over a week, and today suddenly it just died on the desktop. So obviously it's not only a mosfet, not the NCP81161 either.

So I'm back to tinkering with this RX 460 :D It's exactly how this card is wired up. There's one high-side and two low-side mosfets for each phase. Bootstrap capacitor seems to be ok. I can't measure capacitance but I checked the resistance and it's pretty much the same as any other bootstrap...

I checked that on my card and I found a capacitor nearby connected to pin 1 - I pointed it on the image. I'm gonna remove it and check its capacitance later.

I think I won't be able to find where that pad should be connected so I decided to solder a similar resistor on cables to the trace itself, but it's not holding well so I think I will need to glue the cable. What glue do you recommend for such a purpose?

Nothing beeps, my multimeter in continuity mode shows 1966 from broken pad to ground, also 1966 from pad to drain of the mosfet nearby and 1967 from pad to source pin on the mosfet. There's no connection between gate pin and broken pad. Another interesting thing is that from the gate pin to...

There is something and I can probe that. I'm using hot air, but I tried soldering it with the iron first and that's probably why that pad peeled off later in the process of soldering that capacitor with hot air.

I soldered that little missing capacitor on my card but in the process resistor that I soldered back before "peeled off" from the PCB with one of the solder pads. I think I can fix that with little cables but I don't know where it's connected. Do you guys have any tips for finding what it's...

Those RX 460s from Gigabyte don't come with heatsinks on the VRM. That's probably the reason why those cards fail like mine or Kzoak's did.

I have RX 570 in my other PC and I sometimes use dual monitors. Everything is working with the latest AMD driver.

Something similar happened to me before it died. One fan is probably dead now - at least mine was. I thought they are broken because of the initial failure of the card and the card is fine but If that happened to you too I think that there's still a problem on the board even after removing the...

Nice! It's weird that the same mosfet was faulty. I think there's something more to it, but I don't know where to look for a problem as the only thing that I could find is a broken mosfet and the rest seems alright. I hope your card won't die again as mine did after a few days.

I checked capacitors on other similar working card and they behave the same as on my broken card, so that's not the issue and there's no short on the board. But I think I found a problem, I didn't see that before but I lost a tiny resistor and a capacitor close to the mosfet when I was swapping...

Removing low side mosfet didn't helped. Caps are still shorted to ground.

I determine which mosfet needs to be removed by checking for a gate-source short. I will try removing low side mosfet.

I removed the dead mosfet from the GPU and started checking for shorts and I found that most of the capacitors on the VRM are shorted.

There are resistors and capacitors on the board close to every driver but they are not connected to BST. I checked the resistance between Drain and BST again and I realized I was wrong - for every phase even broken one there is ~256 ohms. BST is also not shorted to ground as I mentioned before...

No short to ground on that pin and also no connection between BST and phase output.