Nothing on display - Lenovo IdeaPad 305-15IBD (Mobo: LA-B092P Rev: 3.0)

Hello,
I am looking for help to identify the problem with Lenovo IdeaPad 305-15IBD (Mobo: LA-B092P Rev: 3.0).
I have measured all coils resistance when laptop was switched off.
Naturally all coils voltage was measured when laptop was on.
Regardless to all voltages being present, fan spinning and power light staying on I get no picture on display.
Nothing on external too. From your experience what can be the problem here please ?
Thank you in advance.
Regards,
Rafal S.

Are you testing on low voltage DDR3L (1.35V) RAM?

Hi,
Thank you for your reply.
Yes. It is low voltage DDR3L modules (I have tried each module individually).
I did reset BIOS by removing battery but nothing has changed.
I am hoping that someone had a similar problem and solution/problem is known.
Regards,
Rafal S.

Measure the power consumption (in mA) of the board when the machine is turned on with and without RAM memory connected.

Hi,
Thank you for your reply Matic.
I have 12mA when 20V is applied before switching on.
When switched on:
340mA without RAM (goes down to 12mA after 15-20 seconds).
460mA with RAM module inserted (stays the same).
When I use laboratory PSU I have only 2 pins covered (3rd one - charger detection pin is not connected).
Is this not affecting motherboard behaving ?
Regards,
Rafal S.

You must have power supply detection connected. Insert a 1.5 Kohm resistor between the minus and the third pin of the cable from the lab power supply.

Hi,
Thank you for your reply Mayss,
1,5 kohm resistor was added between minus and detection pin but motherboard is behaving the same.
When switched on:
318mA without RAM (stays the same - not dropping to 12mA)
467mA with RAM (stays the same)
Any ideas please ?
Regards,
Rafal S.

Measure the voltages to ground on pins 1, 7, 8, 9, 11 of LVDS connector JLVDS1 when the machine is turned on with screen connected.

Hi Matic,
I have measured voltages when screen is connected and laptop is on:
1 - 20V
7 - 0V
8 - 0V
9 - 2,4V
11 - 3,3V
Thank you for your reply.
Regards,
Rafal S.

Try to reflash the BIOS chip. Don't forget to save the old dump.
BIOS dump is available on the forum: ***Click***

Hi Matic,
Thank you for your advice and link. I will re-program BIOS tomorrow.
Am I correct that in this laptop BIOS is a part of SUPER I/O and not a separate chip ?
For programming I will have to use keyboard connector in that case.
Regards,
Rafal S.

RafiManch wrote:Am I correct that in this laptop BIOS is a part of SUPER I/O and not a separate chip ?

No, the DUMP from the link is for the MAIN BIOS chip U1 only and there is no part for KBC chip inside it.
The KBC chip has its internal memory and should be programmed with another KBC (EC) DUMP via keyboard connector or out of the board using appropriate adapter.

Reflash the MAIN BIOS chip U1 first.

Hi Matic,
I have programmed BIOS chip with new DUMP from the link provided.
I can see Lenovo logo on the screen and after 5 seconds laptop is rebooting itself.
Process happening in the constant loop.
To make sure the problem is not my old BIOS chip I did program new one with the same DUMP and nothing was different.
What else could be wrong here ?
Any ideas please ?
Thank you.
Regards,
Rafal S.

Try to transplant the ME-region from your old (original) BIOS dump to the new one.
ME-region is located at address "1000", length "17D000".

Hi Matic,
Thank you for your time and help. It is much appreciated.
To transplant ME-region I use HxD software.
I need advice to what format can save modified DUMP to be visible for my programmer ?
It looks like HxD by default is not saving modified file in format .bin even when this type of the file was opened to work on.
Are you using different method or software ?
Thank you as always.
Regards,
Rafal S.

RafiManch wrote:I need advice to what format can save modified DUMP to be visible for my programmer ?
It looks like HxD by default is not saving modified file in format .bin even when this type of the file was opened to work on.

You can save the modified file as *.bin or *.hex. These two formats of files are most common in programming and should be supported by a programmer.
If you have already created a modified file, you can simply rename it to *.bin or *.hex and it should be fine.
Note that the size of modified file should be exactly the same as the file before editing (the file format does not affect to the size).

RafiManch wrote:Are you using different method or software ?

I use the same method and software.

You are welcome.

Hi Matic,
I have changed the file format by simply adding .bin as extension.
Thank you for giving me an easy solution.
After programming with transplant from original DUMP laptop is working again.
I am installing Windows right now.
Your guide and advice were spot on.
Job very well done.
Regards,
Rafal S.