Inno 3D GTX 1060 3 GB diagnosing help

[Prott]

Hello,
I hope somebody more experienced will be able to help me with this weird issue regarding GPU that I am trying to fix. The board is PG410.

Original fault was no vcore. I replaced the UP9509 which made the card behave like this:
1. If I don't plug the 6 PIN in -> the vcore goes to around 0.2 V and something (I suspect MOSFET or a capacitor) emits high pitch sound which is descending. Never waited long enough for it to drop... seems rather ominous.
2. If I plug the 6 PIN in -> vcore goes to 0.8 V and right after (100 ms or so) the high side mosfet of the first phase blows (no visible smoke or sparks, just a dead short on 6 PIN's 12 V to ground).

I replaced high and low side mosfets, the up9509 and still no change. Originally the boot1 resistor was blown (over 100k ohms instead of 0 ohm) so I replaced that - though it didn't change the situation at all.

Without the 6 PIN the vcore stays low despite the fact that REFIN on UP9509 is 0.8 v. COMP and FB are around 0.2 V (the same value as vcore). PSI is 0.6 V. TON is 0.6 V.
Fortunately I also have the same type of card that's working and it seems as if the resistors are the same values on both of them. No components are missing (as far as I can see).

Is the core dead, shorting out the vcore?

[ductranvinh]

Re: Inno 3D GTX 1060 3 GB diagnosing help

Check capacitor near area blow up

[Prott]

Re: Inno 3D GTX 1060 3 GB diagnosing help

Thank you! I removed all the 330uf filter caps that follow the chokes, but still the same result (tested it very briefly).

I also finally plugged in an oscilloscope and have some "interesting" results:
1. PWM for 1st phase high side mosfet seems "okish" - I don't have enough experience to tell, but I am attaching the screenshot. If anything the pulses seems unstable (could be due to the cheap scope) and the ramp down seems a bit too long.
2. There's no PWM for low side mosfets of the first phase.
3. No other mosfets except the 1st phase high side have any PWM signal.

[ktmmotocross]

Re: Inno 3D GTX 1060 3 GB diagnosing help

Check capacitor near area blow up

another useless post. if capacitor was dead whole phase/phases will be in constant short. think before post

[Prott]

Re: Inno 3D GTX 1060 3 GB diagnosing help

UPDATE: I am waiting for replacement up9509 to arrive. It occurred to me that the short caused by higher resistance bootstrap resistor might have destroyed those two previous ones. Will update once I exchange it.

[Prott]

Re: Inno 3D GTX 1060 3 GB diagnosing help

Installed the new 9509 - now it goes to 0.8 V on core and shorts out. I suspect the cap for PHASE1 changed the value (or... I installed a wrong cap to begin with). Will exchange it for a proper 100 nF and update.

[Prott]

Re: Inno 3D GTX 1060 3 GB diagnosing help

So it wasn't the cap. On top of that now I have a different card (also 1060 mini) having the same problem - the original fault was a bad 9509, which changed into bad BIOS (card showing all RAM channels are faulty), which changed into short on U513. And that changed into this same behaviour (once the card is connected it shorts out the first mosfet).

Does anybody please have any tips what can cause this or how to fix it? Thank you