AMD RX 6800 XT no GFX and SOC voltage

[DexMexDC]

Hello, I have one AMD RX 6800 XT and one RX 6700 XT with very similar problem. Both have no GFX and SOC voltage. But lets start with the 6800.

I have experience in electrical engineering and measuring instruments such as multimeters, oscilloscopes, laboratory power supplies, thermal imaging cameras but I just can't get anywhere here.

Let's start with the 6800 XT:
- no visible damage
- No short circuits
- VMEM - 1.35V
- VMEM Controller - 0.89V
- 5V0 - 5.02V
- 0V75 - 0.74V
- 3V3 - 3.27V
- 1V8 - 1.80V
- VDDCR GFX - 0.0V (missing!)
- VDDCR SOC - 0.0V (missing!)

The power controller (IC U500) is an Infineon XDPE132G5D-G000:
- 3V3 on PIN 54 - 3.27V
- VDDCR_GFX_SOC_EN on PIN 48 - 3.27V
- GFX_SOC_PWRGD on PIN 18, 19 - 0.0V
- EN_L2/PWROKon PIN 47 0.0V because GFX_SOC_PWRGD is OV (AND Gate from GFX_SOC_PWRGD and PERST#_BUF)
- PWM channels 1.67V DC, not a single PWM pulse.
- VINSEN PIN 52 - 0.84V

What else should I measure? What could it be? Is the U500 itself defective or is there an input missing?


https://www.badcaps.net/forum/troubl...36#post3546836

[прямо]

0V at PG output = chip is dead.

[ktmmotocross]

0V at PG output = chip is dead.

???

[прямо]

???

??????

[ktmmotocross]

??????

what chip is dead and why?

[прямо]

what chip is dead and why?

See his post. Phase controller chip doesn't output PG (power good), but it has EN signal and supply voltage. That's why I said it's dead.

[ktmmotocross]

See his post. Phase controller chip doesn't output PG (power good), but it has EN signal and supply voltage. That's why I said it's dead.

pg signal is released when output is ok. why u expect controller to output pg if there is no output? there is even other signals that can prevent ic from make output