Lenovo B560 fluctuating DC

[whaldsz]

I got this laptop where The voltage at D1(see page 46 in the attached schematic diagram) is fluctuating. Using power adapter,

What i tried:

1. TPS51123 is overheating so i replaced it with a new one.
2. tested the mosfets, no short found.

Havent tested the board using the battery. Any idea where the problem is? I also have acer 5570 zr1 with similar issue.

[jtamad44]

Re: Lenovo B560 fluctuating DC

try everything you know and if the problem stll the same post back everything you did in the past.

[tomodachi]

Re: Lenovo B560 fluctuating DC


Try to desolder these coils one by one and measure if there is a short

[whaldsz]

Re: Lenovo B560 fluctuating DC

Thank you for your reply.

I already measured the resistance from those those coils to ground but there are no short. Tried replacing U7 - BQ24745 charger IC but same problem. the voltage at D1 fluctuates wildly. I will try to remove U38 and U37 and post bact the result.

[Techie666]

Re: Lenovo B560 fluctuating DC

Have you tested the dc adapter? I would put a load on the adapter alone (connect a 12v fan or something) and measure with volt meter to see if the voltage goes down. it should stay steady at almost the rated voltage. if voltage drops more than 1 volt try another adapter.

[whaldsz]

Re: Lenovo B560 fluctuating DC

Yes, adapter is fine. Tried another known good adapter still the same.

I will try to remove the coil as suggested by tomodachi and measure the voltage across D1, will post back the result.

[nataf10]

Re: Lenovo B560 fluctuating DC

Hi there!
I have also a dead motherboard that not power on.
Have you fixed your at last?
Can you please upload or send me the correct schema for this LA56 mother board?
Please advise.
Regards.

[tiak]

Re: Lenovo B560 fluctuating DC

Hi,
Where is : attached schematic diagram ?

[BenCesur]

Re: Lenovo B560 fluctuating DC

Thank you for your reply.

I already measured the resistance from those those coils to ground but there are no short. Tried replacing U7 - BQ24745 charger IC but same problem. the voltage at D1 fluctuates wildly. I will try to remove U38 and U37 and post bact the result.

Hey.

I need this scheme. (b560) Would you please add?

Thank you.

[ravindra]

Re: Lenovo B560 fluctuating DC

Hi,
I have same Problem. My laptop suddenly died, no warning that I could see, I was watching a video and wasn't paying the best attention, but there were no noises. The screen just went black and the computer died.
The orange light on the power adapter is solid when it's not plugged it, when it plugs it, the light goes out and then blinks twice, dark for a second, then blinks twice again and repeats.

Please help me, and also please provide me it's schematic diagram, if some one have

Thank you

[cyberhack]

Re: Lenovo B560 fluctuating DC

this LA56 mother board

[attila123]

Re: Lenovo B560 fluctuating DC

Hi guys!

I have big problem with a Lenovo B560 with LA56 MB motherboard. I probably shorted out the LVDS connector at display. When I tried to turn on the notebook nothing happened, only power led is flashing very slowly. When I plug in AC the power led starts flashing every about 10 sec for 1 sec or less, no fan is working.

How can I fix it? Which power IC could damaged?

Thank you!

[rajeshkumar]

Re: Lenovo B560 fluctuating DC

hiiiiiii frnd need b560 la56 schematic diagram
dimm display problem facing

[emr2000]

Re: Lenovo B560 fluctuating DC

b560 diagram

[angel-boy]

Re: Lenovo B560 fluctuating DC

Hi friends, I have a problem with the motherboard laptop lenovo b560

- i have 3 boards, all power on , but when i want to shutdown , when power led from power button and power led near charge led, remains on !

- i change the bios same problem , i dont know what to do !!!

about the problem - http://*******/viewtopic.php?f=58&t=23204
If you have an account please give me some bios ,i dont have enough posts to download bios

[dj_ricoh]

Re: Lenovo B560 fluctuating DC

get the files from there if you can!

[angel-boy]

Re: Lenovo B560 fluctuating DC

Did you read ? " If you have an account please give me some bios ,i dont have enough posts to download bios "

i cannot get files from there. if someone can help me , please help me .

[khaahk]

Re: Lenovo B560 fluctuating DC

from another source but also for LA56

[angel-boy]

Re: Lenovo B560 fluctuating DC

you give me EC , not main bios, please if you have a working bios file , from a lenovo thats shutdown

[angel-boy]

Re: Lenovo B560 fluctuating DC

I partial solve the problem of lenovo, now is shutdown , but when power up , lenovo logo appers late, and the fan allways is on.