Dell G3 15 3500 RAM issues

[loic2907]

Hi,
On this laptop Dell G3 15 3500 Wistron Selek MLK N18E 19753-1, I have 2.3 blink meaning no ram detected.

I tried multiple BIOS and same.

Have all voltage (VCCIO /CORE / SA; 3V 5V, VRAM, GPU..) except VCCGT.
On the RAM side, have voltage of 1.2V, 0.6V, 2.5V and the PGOOD.

Have 3V on the 3V3S0 coming in the ram socket, and the voltage of CLOCK and DATA coming from PCH to RAM...

I am running out of idea if someone has one..

Thanks in advance

[Techtiger]

Re: Dell G3 15 3500 RAM issues

The guidelines was given out the schematic, To troubleshoot the issue, consider testing the DRAMRST signal on the RAM slot pin 30 supply and the power good signal +2.5V! Ensure that the power good signal is not less than what the EC expects.

[loic2907]

Re: Dell G3 15 3500 RAM issues

Ok, my bad, I didn't give the information !
DRAM_RST is low (0.1v) (it's on the pin 108 of the slot, 30 is GND)
The pwr good signal for 0.6, 2.5 and 1.2 is the same (same chip for all) named PWR_VDDQ_PG.
This power good signal enable VCCIO, and it return to EC with R4035 (RUNPWROK) and it is present too.

[MOD EDIT]
Link to schematic/Boardview - https://www.badcaps.net/forum/showthread.php?t=114669
.

[mcplslg123]

Re: Dell G3 15 3500 RAM issues

DRAMRST# is present on pin30 for DDR3 and 108 Pin for DDR4.

This reset signal is from CPU so may be cpu is faulty. Quite a common problem. However, if SDA/SCL communication is not proper,dramrst# will be pulled low by cpu. Sometimes its the bios.

[loic2907]

Re: Dell G3 15 3500 RAM issues

You sure it is from CPU ?
In this motherboard it goes through R1581 and become SM_DRAMRST which go to the PCH, it is pulled high to 1.2V at the same time.

Tried a lot of BIOS, for those which boot, same issue.
Tried to replace BIOS Region in FIT. Same issue
My BIOS is 1.24 tried to replace ME Region after extracted the 1.24 BIOS from dell website, same issue.

[loic2907]

Re: Dell G3 15 3500 RAM issues

PCH changed, SMC changed, same issue

[mcplslg123]

Re: Dell G3 15 3500 RAM issues

100%, I'm sure.Ram is reset by CPU and not PCH but certail conditions has to be fullfilled before cpu will reset the ram(DRAMRST#) and one of the most important requirement is communication with PCH on SMBUS via SDA/SCL.

[loic2907]

Re: Dell G3 15 3500 RAM issues

For you, i need to replace the CPU ?

[mcplslg123]

Re: Dell G3 15 3500 RAM issues

Have you checked sda/scla communication on ram slot?

[Deniz]

On these series motherboards, if the RAM is faulty, you will see a value such as DRAM_RST 0.1v. So don't let this fool you, the ram is probably faulty.
Unfortunately, I learned this through painful experience