Lenovo Ideapad Flex 5 14ITL05 Only working on external display

[lawrenceptrini]

Hi Guys,

LENOVO IDEAPAD FLEX 5 - 14ITL05
BIOS VERSION - FXCN24WW
EC VERSION - FXEC18WW
MTM - 82HT0004US
SERIAL NUMBER - R9130MDP
CPU - i7-1165G7

This laptop powers on but shows nothing on the internal display.
However, if I attach an external display it works fine.

Observations: When I shut down the laptop from windows,
the fan remains spinning until I close the lid. If I leave the lid open
the laptop will restart on it's own although I select shut down from windows.
Also, when I check the voltage on the LCD connector (19V_DCBATOUT_LCD) I'm getting 12.80v.

I have attached the schematics for the motherboard and will appreciate any assistance in this issue. Link to schematic --> https://www.badcaps.net/forum/troubl...33#post3204733

[reformatt]

Uses a NVDC power supply, so main power rail is around the same volts as the battery. So 12V or so is normal despite what the schematic says. Have you established that the display is ok first? Or image present with no backlight perhaps?

Voltages on LCD connector after initial power on?

[lawrenceptrini]

Hi,
Thank you for your response.
I haven't remove the screen as yet as it's adhered with adhesive to the casing. So no, not certain if it's ok.
I wanted to know if it's a familiar event with this model and if there's a solution without having
to remove the screen.

I now understand why I'm getting 12v on the LCD connector, thank you.
Haven't seen a backlight image. When turned on, no flickering, and no feint image when I shine a light on it.
Yes I'm getting 12v when the laptop is turned on.

Any other voltages to check? or you suggest I heat up and remove the screen and see if I can get it tested first?

[reformatt]

3D3V_LCDVDD_S0
3D3V_S0_GS1
3D3V_AUX_S5
BL_ON

These voltages should come up initially at power on, may disappear if no communication is received from the display. Usually faulty display is the most common. Look at the display from an angle and you can usually see marking where it's damaged. These displays are held in with removable tape that you pull and stretch to release. If memory serves, the tape runs up each side but angles towards the middle at the bottom. The official replacement tape from Lenovo isn't cheap either. I have a roll of 6mm pull release tape that I use to fashion a replacement.

Swap the entire display assembly from another machine is probably the most easiest.

[lawrenceptrini]

Hi,
Thank you.
I will check if the voltages you stated stays present or disappears therefore hinting there's no communication from the display.
I'll also have another careful look at the display to see if there are lines or markings to confirm a damaged screen.
Yes, you are right there's stretch adhesive on both sides of the screen, if the measures above doesn't bear fruit then I'll remove the display/or full assembly and get it tested.

will report my findings.
thanks again.

[lawrenceptrini]

Hi, @ reformatt

I am getting these voltages:

3D3V_LCDVDD_S0 - 0.001v
3D3V_S0_GS1 - 3.325v
3D3V_AUX_S5 - 3.385v
BL_ON - 0.000v

13.3v on 19V_DCBATOUT_LCD

please advise....

[reformatt]

Appears that 3D3V_LCDVDD_S0 is missing. Should be enabled by power switch U5501. Check for 3D3V_S0 on pin 5, and eDP_VDD_EN_D on pin 4 should go to 3.3V when the system is booted. This may be subsequently disabled if communications with the screen are not established.

[lawrenceptrini]

Hi,

Thanks for you response.

With black Multimeter probe on ground and red on pin 4 of U5501 IC when I turn on power I'm getting 0.001v.
When I repeat this procedure on pin 5, I'm getting 3.385v.

[lawrenceptrini]

Hi,
Reporting the follow up to this issue.
I ended up purchasing a used motherboard. After removing the motherboard from the box, I put on the heatsink and tested with an external monitor and got display. I then peeled back the protective layer and located the U5501 ic.....I checked 3D3V_LCDVDD_S0 and got 3.3v, then checked eDP_VDD_EN_D and also got 3.3v. So I then connected the internal screen and the display came on. Thanks for the assistance, it appears possible faulty PCH/CPU.