Acer G9-593

[moscast]

Hi everyone, this is my first post and I hope I'm not making a mistake.

I'm struggling with a repair of an acer predator g9-593. It doesn't turn on.
On the RAM coil I have 1 ohm and it doesn't seem normal to me.
Could someone tell me how much more or less it should be?

Thank you.

[mcplslg123]

1 ohms on ram coil-CPU is very likely shorted. Remove the ram coil and see which side is shorted. If the produce side is shorted,then either the PWM/mosfet may be shorted. However,very likely short is on the consumer side. The resistance to GND on ram coil is definitely in hundreds of ohms.

[moscast]

Hello and thanks for the reply. In fact, when I raise the RAM coil I still have the short. So I tried removing two RAM modules but the short persists. By measuring on the two modules between Vss (GND) and Vdd I noticed that I have 1.2 Ohm (I based it on the diagram I attach). Is it possible that both modules are short-circuited and that there is still a short in the board anyway?
I'll try to remove all the Ram modules (6 in total) and if I still have the short maybe it's the GPU.

[mcplslg123]

After removing the ram coil,which isde of coil is shorted and what is the exact resistance to GND on the shorted side?

[moscast]

The short circuit is in the RAM part. In fact, the vdd of the ram measures 1.05 ohm to vss (gnd). What I don't understand is that by removing two ram modules, they always measure more than 1.2 ohm between vdd and vss. Is it possible two out of two we are short? Then probably the others on the motherboard are too. Looking at a boardview of a similar card, I notice that the trace that goes to the VDD of the RAM also goes to the GPU pins. Anyway, in my opinion I should try, at this point, to remove the other RAMs. What do you think about it? Thanks again.

[moscast]

I removed all the RAM modules and only two measured 1.2 ohm, the other 4 (between vdd and vss) measured 60 ohm.
However in the coil output I now have 5.3 ohms
I don't know what to control anymore.

[mcplslg123]

Memory controller inside CPU is shorted.

[moscast]

Memory controller inside CPU is shorted.

Hi, thanks a lot for your support. Last question: you mean is shorted inside GPU (in my case invidia) not CPU (Intel) right?

[mcplslg123]

Ram is controlled by CPU and not GPU-so its CPU fault.

[moscast]

Ram is controlled by CPU and not GPU-so its CPU fault.

Sorry but in a similar BoardView the Vdd (+VBFDDQ) that i have shorted is not connect with CPU. I add a screenshot of boardview
Can you explane me?

[mcplslg123]

OMG.You mentioned ram coil is shorted so i assumed you are talking about the ram coil which is supposed to be 1.2V for DDR4. But now i find that you're talking about VRAM coil and not Ram Coil. The resistance on VRAM coil seems fine to me.

[moscast]

OMG.You mentioned ram coil is shorted so i assumed you are talking about the ram coil which is supposed to be 1.2V for DDR4. But now i find that you're talking about VRAM coil and not Ram Coil. The resistance on VRAM coil seems fine to me.

Sorry, I didn't explain myself well. Ok, you said it's right to have 5.2 ohms after the VRAM coil even though I removed them all. However two of six of these modules have between Vdd and Vss 1.2 ohms the other 60 ohms. So two need to be replaced. I hope to find that model of ram because I can't find them when I search. There is no specific model written. The logo is a stylized "M".

[mcplslg123]

Yes,to me the resistance to GND on Vram coil seems fine as GPU rail shows low resistance to GND. May be others can opine on it to confirm.

[moscast]

Hi everyone, I wanted to revisit this post and ask you what I can still try:

in the motherboard of an acer predator 15 G9-593 I removed all the Vram because I had a very low resistance between the Vdd and Gnd 1.2ohm.
Once I removed the Vrams (6 modules) I noticed that the resistance had risen to 5.52 ohms.
I reinstalled all the new Vrams and the resistance to ground is still the same as 5.52 ohms

Unfortunately I don't have any videos. The laptop turns on but the screen remains black.

Now I have these questions:
- it is correct to have a resistance to ground of 5.52 ohm in the Vrams because in my opinion it is very low. I think it should be around 250 ohms.

- is it possible to start mats automatically and then read the error log to understand if some Vram module is not working?

Thank you

[Sephir0th]

It is true that the main rails related to the GPU, measure very low compared to GND,. However, for the VRAM rail it is so, that the exact resistance to GND depends on the installed VRAM modules. Iirc with Samsung modules you will notice lower values than with Micron modules. Should not be lower than 20 or 30 Ohms.

Alone from this observation you can conclude that the resistance to GND of this track has to raise above the value of the VRAM chips.

Sorry, but 5 Ohms is too low. The Memory Controller inside of the GPU has died.

[moscast]

It is true that the main rails related to the GPU, measure very low compared to GND,. However, for the VRAM rail it is so, that the exact resistance to GND depends on the installed VRAM modules. Iirc with Samsung modules you will notice lower values than with Micron modules. Should not be lower than 20 or 30 Ohms.

Alone from this observation you can conclude that the resistance to GND of this track has to raise above the value of the VRAM chips.

Sorry, but 5 Ohms is too low. The Memory Controller inside of the GPU has died.

Thanks a lot for your answer. Mayby I'll replace the gpu. I'd like to try that.