Need help for ASUS strix z690 D5

[McWhitePink]

I got a Z690-G, DDR5.
The VDDQ is very low, only 1.1v, checked the REF voltage is coming from the TPU chip KB3724Q. If I use external power supply to supply 1.2V VREF, VDDQ will become 1.2V.
I swapped the TPU chip from a good board, known as 1.2V VREF, but on this board it still giving 1.1V.
Does anyone know how this reference voltage is generated from the chip? what components can impact the value?
I then measured the DDR5_PWR_GOOD pin, always low. It should be active high.
Please help !

[piernov]

Re: Need help for ASUS strix z690 D5

What's wrong with 1.1V?

[McWhitePink]

Re: Need help for ASUS strix z690 D5

What's wrong with 1.1V?

DDR voltage should be 1.2,
1.1 will be too low and won't work

[McWhitePink]

Re: Need help for ASUS strix z690 D5

What's wrong with 1.1V?

maybe you are right, the issue is not due to 1.1V, but something else.
PRW_GOOD is an open drain on DDR5, so it might be the DDR5 chip pulls it down. That means there is still a power issue, but I couldn't figure it out yet.

[anikin73]

Re: Need help for ASUS strix z690 D5

Check the ic that gen Pwm. Then check the ref pin. Usually is 0.6 or 0.8v. There are 2 resistors .. have to change one of them

[anikin73]

Re: Need help for ASUS strix z690 D5

Can get a similar model or 1 gen lower board view. Could be similar.

[DynaxSC]

Re: Need help for ASUS strix z690 D5

Hi my friend,

For DDR5 the memory modules are supplied only by one +5V voltage, and all other voltages are generated inside the DDR5 module, so there is in fact no VDDQ voltage generated on the motherboard.
Pls note that the DDR5 pinout is quite different from DDR4.

Pls find attached link to a similar BV for ASUS Prime Z690-A Wi-Fi D5.

https://www.badcaps.net/forum/showthread.php?t=125039
.

[McWhitePink]

Re: Need help for ASUS strix z690 D5

I finally figure out there is a transistor not functioning correct.
the transistor controls the DDR5_PWR_EN.
But I still don't understand the reason why it uses a transistor but not MOSFET for the control.
Since I don't have a transistor in my hand, I just changed a MOSFET for it. and it also works.