Laptop doesn’t post,Fan spins constantly, sometimes it does post and display

[mnciks11]

Hello guys

A Lenovo V310-15IKB
DA0LV6MB6F Rev : E

Laptop turns On, i have the green light, it charging but it doesn't post no display no nothing. But when you keep on turning it On and Off it start normal, post and work normal.

I checked the ram power supply coil i have 1.2v and when i check the ram itself it shows me 2.5v

Kindly see attached photos, on those two coils i have 0v even if it does start normal and work but still i have 0v

What must be the issue?

[KvnTM]

Re: Laptop doesn't post,Fan spins constantly, sometimes it does post and display

2.5V is waaaay too much for ddr4!
Also why is there a component missing?

[mnciks11]

Re: Laptop doesn't post,Fan spins constantly, sometimes it does post and display

2.5V is waaaay too much for ddr4!
Also why is there a component missing?

Thanks for responding, jah true 2.5v is way too much for ddr4, but the laptop does work if you i keep on tryin and the ram was 2.5v but it was working fine I didn't anything wrong...my friend im really confused and I can't find the schematic

[KvnTM]

Re: Laptop doesn't post,Fan spins constantly, sometimes it does post and display

Thanks for responding, jah true 2.5v is way too much for ddr4, but the laptop does work if you i keep on tryin and the ram was 2.5v but it was working fine I didn’t anything wrong...my friend im really confused and I can’t find the schematic

Im pretty sure it is because of the missing component. Looks like some output cap of a buck regulator. This will cause the buck regulator to become unstable and possibly overshoot its voltage target.
Can you confirm that this is the rail for ddr voltage? I marked it red in my last reply.

[mnciks11]

Re: Laptop doesn't post,Fan spins constantly, sometimes it does post and display

Im pretty sure it is because of the missing component. Looks like some output cap of a buck regulator. This will cause the buck regulator to become unstable and possibly overshoot its voltage target.
Can you confirm that this is the rail for ddr voltage? I marked it red in my last reply.

Okay i will use the continuity mode to confirm if on the same power rail with the ram power supply, i will keep you updated and thank you so much

Wait you think there is chance for ceramic capacitor to move out of the board easily like that ?

[KvnTM]

Re: Laptop doesn't post,Fan spins constantly, sometimes it does post and display

Okay i will use the continuity mode to confirm if on the same power rail with the ram power supply, i will keep you updated and thank you so much

Wait you think there is chance for ceramic capacitor to move out of the board easily like that ?

Even if it is not the ram rail you must put a cap there. A failing power rail would hinder the system to POST. There are no schematics or boardview available. I'll try to find a high res photo of that are though.

You can very what the rail is for in the meantime. Yes, continuity (diode) mode and look where that rail goes to. Disconnect all power from the board when doing that!!

EDIT: Actually, this component doesn't have to be populated. Why does it look like something has been ripped of the board? I found a clear picture of the area.


But you still have a problem on your ram power rail. Are you sure your measurement was correct before? Confirm ram voltage again please.

[mnciks11]

Re: Laptop doesn't post,Fan spins constantly, sometimes it does post and display

Even if it is not the ram rail you must put a cap there. A failing power rail would hinder the system to POST. There are no schematics or boardview available. I'll try to find a high res photo of that are though.

You can very what the rail is for in the meantime. Yes, continuity (diode) mode and look where that rail goes to. Disconnect all power from the board when doing that!!

EDIT: Actually, this component doesn't have to be populated. Why does it look like something has been ripped of the board? I found a clear picture of the area.


But you still have a problem on your ram power rail. Are you sure your measurement was correct before? Confirm ram voltage again please.

Yes i even changed the ram and measure the ram ceramic capacitors they give me 2.5v but when i measure the output coil of the ram piwer suplly i get 1.8v

[KvnTM]

Re: Laptop doesn't post,Fan spins constantly, sometimes it does post and display

Yes i even changed the ram and measure the ram ceramic capacitors they give me 2.5v but when i measure the output coil of the ram piwer suplly i get 1.8v

Are you sure that you measure on the correct caps? Also 1.8v is still way too much. Take a look at the feedback circuit of the ram power supply. Maybe there's a blown/corroded resistor somewhere. Make sure all components are ok.

[mnciks11]

Re: Laptop doesn't post,Fan spins constantly, sometimes it does post and display

Are you sure that you measure on the correct caps? Also 1.8v is still way too much. Take a look at the feedback circuit of the ram power supply. Maybe there's a blown/corroded resistor somewhere. Make sure all components are ok.

Thank you so much 😊 let me check it