Lenovo E14 replaced ddr4 memory module resulting in no boot

[ongobongo]

I am still working on an Lenovo e14 AMD notebook with some problems. The laptop booted normally but had a ton of problems with the soldered ddr4 memory. I tried deactivating the memory via bios, but that didn't work.
As i have a matching donor here, I decided to change the module i suspect to be faulty and exchange it with one of the donors.
Did so, but now the laptop won't boot anymore.
Anyone here who already did that and can comfirn, that exchangeing one module alone would work? Or do I need to exchange all 4 of them to make it work?

[alexfts20]

ongobongo Could you please provide the model name from the board? For example, (NM-C771).

[ongobongo]

sure, it is actually GE420/GE520 NM-C771 Rev: 1.0
Both models use the exact same memory modules from Samsung: k4aag165wa-bcwe

[Sephir0th]

Sounds to me more like bad replacement part or part not correctly soldered. Or, the faulty Chip finally died because of the heat.

[ongobongo]

Yah, that was is my thinking as well. This is the first time I had to deal with underfil and i could easily used too much heat to get rid of it.
Just thouhgt I ask if this is kind of module change needs to be done for all of them or if one is just fine.

[alexfts20]

ongobongo Try disabling the onboard RAM by moving the board ID resistors as shown in the attached photos:

[Sephir0th]

Yah, that was is my thinking as well. This is the first time I had to deal with underfil and i could easily used too much heat to get rid of it.
Just thouhgt I ask if this is kind of module change needs to be done for all of them or if one is just fine.

It is enough to replace the faulty chip(s).

[ongobongo]

alexfts20, you my hero of the day. I had already looked at the memory configuration via resistors before, but as there was no option for deactiving the onboard memory, i didn't bother to dig any further. Now, with your feedback, I gave it a try and changed the config to one of the reserved ones (111) which actually disables the onboard modules :-)
Thanks a million
ongo

[alexfts20]

ongobongo You're welcome, ongo! I'm thrilled to hear that the solution worked and your problem is resolved. 😊

[eaf]

alexfts20, you my hero of the day. I had already looked at the memory configuration via resistors before, but as there was no option for deactiving the onboard memory, i didn't bother to dig any further. Now, with your feedback, I gave it a try and changed the config to one of the reserved ones (111) which actually disables the onboard modules :-)
Thanks a million
ongo

Hi ongobongo and alexfts20 , I have the same issue and I'm new here. could you explain a little what you did? thanks,

[ongobongo]

This Board has 6 six positions for resistors (RC110-RC115) that define the internal board id and, with it, the type and size of on-board memory, see picture attached. Three of those 6 positions are populated with a 10K resistor each.
Depending on the combination of the populated resistors, you define a board id. If you have a similar board you will have one of the first six combination from the list attached. I changed my combination to one of the two "reserved" states.
To be more precise you need to make sure that the positions RC110, RC112 and RC114 are populated with a 10K resistor, while the others (RC111, RC113, RC115) are open and not populated.
Then you are in a reserved state that doesn't define any on-board memory. You must use a stick of memory to get it to boot.

[eaf]

Thank you ongobongo. that's very helpful.

[eaf]

Hello ongobongo, alexfts20 I finally followed this and fixed my E14. Thank you! you are my hero of the day