Hi I have a RX 580 GAMING X which uses IR35201 PWM controller. I am missing vcore voltage. I want to check if any other voltages or signals are required for this PWM controller to work.
Привет, у меня есть RX 580 GAMING X, в котором используется ШИМ-контроллер IR35201. Мне не хватает напряжения vcore. Я хочу проверить, требуются ли какие-либо другие напряжения или сигналы для работы этого ШИМ-контроллера.

What is the resistance of the core? I had today such card and it had 0.4 ohms if I remember. This card had tendency to go dark. After some time it degraded to 0.2 ohms and PWM refused to start. All other voltages and resistances are good. 0.4 ohms is too low and should be 0.5-0.6.

0.7 ohms

Do you see sampling of VRM just after powering up? Set the scope to normal triggering, not auto. Set the trigger level to lets say 5V and wait for falling edges. You should see several very thin pulses which stop almost instantly as they appear. It would mean that VRM is trying to start. Do you have thermal cam?

I don't have an oscilloscope but I do have a thermal camera. I know the PWM is starting because there were some faulty power stages which resulted in blown MOSFETs and gate drivers. I have replaced all of the faulty stages, as well as the 2.2R boot strap resistors. I can see that VRRDY_L2 is being pulled down to 0V and since I have memory voltage and no vcore voltage I guess L2 must refer to vcore.

It is MSI, what is the board number and version? There are schematics.
Do you see the GPU to become warm for a second after power on on the thermal cam? In general you need a scope for such repairs.
If it tries to start it means that enable is present, enable most likely comes from the 3.3V through some gates or transistors. You need to find out if you have overload condition or what.
Please post images of both sides in good quality, big and sharp jpegs, and write more detailed history.

I have the schematics. 3.3V comes from 3.3V_BUS, which I obviously have as per my first image. When I measure the resistor PR47 it is 0V on the side of the IR35201. PR47 measures correctly at 4.7K. My understanding is that that means the PWM controller is pulling this pin down to 0V

I asked you about board number and revision version....

VRDY2 - Voltage Regulator Ready Output (Loop #2). Open-drain output that asserts high when the VR
has completed soft-start to Loop #2 boot voltage. Pull-up to an external voltage through a
resistor.

VRDY Delay1 After reaching Boot voltage 20 µs

POWER-ON SEQUENCING
The VR power-on sequence is initiated when all of the
following conditions are satisfied:
IR35201 Vcc (+3.3V rail) > VCC UVLO
Input Voltage (VINSEN rail) > Vin UVLO
Aux Voltage (VAUXSEN rail) > VAUXSEN
UVLO(if configured)ENABLE is HIGH
=== THIS ===
VR has no Over-current, Over-voltage, Over-temperature or Under-voltage faults
Don't you have overcurrent condition? Did you check NTC?
==========
MTP transfer to configuration registers
occurred without parity error
Once the above conditions are cleared, start-up
behavior is controlled by the operating mode.

V341 3.0. I have 0V on VR_HOT# which is active low, so I guess that means PWM controller is pulling that to ground? Which means I must have an error on TSEN. but TSEN eventually leads to a via according to the boardview?



Which I guess means the issue must be with ISEN on one of the phases?

Inject 0.7V to the GPU core and watch it on the thermal camera. Some GPUs have normal ohmic resistance but when you apply real power there is a big short activated by the supply voltage. And post some pictures or upload movie somewhere.