HP 15-bs001ni No image

[ebyte64]

Good afternoon.

I am at my wits end with a HP 15-bs001ni laptop I am working on. It power on but shows no error codes on the caps lock or num lock and no image on screen or backlight on screen.

Motherboard model is C5L50/C5L52 LA-E811P Rev 2.0

Measuring voltages on the incoming mosfets are good. 19v on source and drain and 25v on gate for both the high side on low side mosfets.

Memory voltage of 1.3v is present.
Cpu/chipset power supplies has 1v
EC chip has 3.3v and starts up the other power supplies.
Bios chip has 1.8v
usb ports have 5v
Monitor has 19v but strangely I cannot find the 3.3v on the screen connector.

The board draws 10MA when powered off for the 3.3v LDO and 230MA when powered on. The board also does not display to an external monitor.

I initially thought it was a bios issue. A forum member was kind and provided me with a bios but still the same issue.

I cannot feel anything get hot on the board that is out of place. Sadly I do not have a thermal camera.

Would anyone perhaps have any idea what issue I might be having?

[Stevedb]

Re: HP 15-bs001ni No image

Hi does the laptop reacts on caps/numlock? Do you have picture on hdmi? Or with flashlight?

[ebyte64]

Re: HP 15-bs001ni No image

Hi, sorry I left out some details. No, no caps lock or num lock reaction. No picture with the flash light test and no picture over HDMI. The motherboard does show error codes on caps lock when I remove the ram. But testing other sticks also does not produce a change.

[Stevedb]

Re: HP 15-bs001ni No image

Did you try also external keyboard or ctr alt delete to see if the laptop is posting . Then it is time to see hd picture with all coils voltages. How did you flash bios did you also clean me region if it is intel bios.?

Regards

[ebyte64]

Re: HP 15-bs001ni No image

I tried an external keyboard and nothing. As for the bios I uploaded a backup copy to the bios request forum and was given a clean bios with the correct DMI information added. I flashed it with the CH341 programmer.

[Sephir0th]

Re: HP 15-bs001ni No image

Share resistance to GND measurements of the secondary power supplied please and also take a look whether you can get a VR_RDY from the VRM Controller.

[mcplslg123]

Re: HP 15-bs001ni No image

DRAMRST# present?

[ebyte64]

Re: HP 15-bs001ni No image

I am fairly new to component level board repair in still learning. Where would the vrm controller be? I would assume near the cpu? I have attached an image so long with the resistance values as requested. Thank you all for your time.

[ebyte64]

Re: HP 15-bs001ni No image

mcplslg123, regarding your question I do believe it is. I do believe it should be in the aria encircled on the picture attached if I am correct? I get 1.35v there. Forgive me I doon't have a schematic or board view for this board so I am unsure.

[ebyte64]

Re: HP 15-bs001ni No image

My apologies I seem to have been an idiot and way overcomplicated it for myself. It was just faulty ram. Thank you everyone for your suggestions and time.

[mon2]

Re: HP 15-bs001ni No image

Your update is appreciated for closure.