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An i7 gaming laptop released in September 2017. Created to fight heat and keep air flowing with thermal engineering systems.

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Help me troubleshoot my Motherboard

Hi everyone,


I have a lenovo legion y520. I wanted to replace the keyboard because the O key wasnt working anymore. Its an embeded keyboard in this laptop.

Anyway I replaced it.

After that, I maybe damaged something in the motherboard. The cable linking the lcd screen and the mobo burnt because I connected it after the battery.

So now I have several issues.

First the powerbutton seems to be damaged

Before :

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https://www.noelshack.com/2019-50-6-1576...

Mine :

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https://www.noelshack.com/2019-50-6-1576...

So I have to take a small aluminium circle that felt from the case to make contact with a circle area in the mobo. When I do that the Mobo start (white led)

Here with the mobo only

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https://ibb.co/XjpYBmC

Here When i connect the IO cable with its interface I have two white leds

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https://ibb.co/0f8s1C6

The fans wont spin

I dont know if the fans have to spin anyway. I dont know how to test if something is damaged. Indeed the lcd cable seems to be burn so Even if I connect the laptop with a hmdi screen I have nothing.

Look at this video I did : https://streamable.com/hzz5v

Someone can help me troubleshooting this ?

Sorry for my bad english ^^

Update (01/04/2020)

The connector seems to be ok even if the plastic burnt a little. The metal connectors seems to not be damaged.

But the lcd cable ( I ordered a new one) burned.

Here some pictures

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I dont know if the laptop is working or not because there is no display and the fans dont turn on…even if I plug a hdmi display.

I heard that heating the Mobo can be a solution

Mise à jour (09/01/2020)

Thanks for your help.

I ordered a power button and display cable.

Do you think this kind of power button is OK ?

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Also, is it possible that this screw is responsible for not let the laptop boot normally ?

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Note that this part is connected with the CMOS.

Normally the screw has to be in the metalic support like here

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this part

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By mistake screwed directly on mobo and…the screw is now broken impossible to extract, I will cut it gently to unscrew it with a flat screw driver.

Update (01/09/2020)

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The connector seems to be ok ?

Answer this question I have this problem too

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oku ytr your dispaly cable should not get hot no should it "The cable linking the lcd screen and the mobo burnt because I connected it after the battery". Heat equals short circuit. REmove the cable and carefully inspect the end of it. See if there are burn marks etc. on it. It may be shortening the conector out; inspect that as well. Explain this "I have to take a small aluminium circle that felt from the case to make contact with a circle area in the mobo" a bit more. There is a possibility that your original power switch only momentarily closes the circuit to turn your laptop on. Your laptop may not be designed to keep the circuit closed to whole time.

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Hi thank you. I updated my post.

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I have the same problem

Opened the laptop to replace an SSD and my static might have burned something. It happened just now and I'm really depressed. White led indicator turns on, but everything else looks turned off. I don't know where to look to be sure if the mobo is dead or not.

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Hi! Please tell where did you buy the power button from. I need one like this. Thank you.

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Hey. Have you fixed it? I'm having the same issue and idk what to do...

Did changing the LVDS cable solved the problem?

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2 Answers

Most Helpful Answer

oku ytr  okay so you want to start by repairing what you know has failed. Number one being your power switch. The fan will not come on since it is turned on/off by the thermal sensor (temperature depended). Your LCD cable should not heat up at all. The first thing to check is the cable end and the connector (should be JEDP1). Check the cable ends and the connector for burn spots, broken pins etc. Here are the schematics for your motherboard. You may need those after you replace the switch and investigate your LCD connector

y520_mb_n17p SchematicY520 Test PointsY520_IO DB

Update (01/04/2020)

Okay definitely shows burn marks on connector and cable. That is where your short circuit comes from. Pin 5 is NA (not connected) but pin 6 is the power line for your LCD. Hard to see on the cable but it looks like the contacts burned off. you may need a new assembly or check to see if the cable itself is replaceable. You may also need a new LCD connector.

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If I inspect carefully the lcd connector it seems that its just the plastic that melt a little. The metalic pins seems to be Ok. Can I test it ?

I ordered a new LCD cable. If the connector have to be replace, do you know were I can find one (aliexpress?) What i have to search for.

Why it doesnt start normaly if I disconnect the lcd from the mobo and connect a hdmi display ?

The power switch seems tricky to repair. It seems that it was a little plastic that holds the metalic circle and when you press the power button it makes contact.

Here some pictures

Metalic circle that felt

https://ibb.co/vZgkmwV

https://ibb.co/V2bK1GR

Normal power switch

https://www.noelshack.com/2019-50-6-1576...

What I have

https://www.noelshack.com/2019-50-6-1576...

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By the schematic it looks like a Push button Switch Momentary (On). So you could in theory solder a remote switch via some wires etc. It does not have to be closing the circuit the entire time.

Your LCD connector will not work properly since it is the plastic that has melted. The small metal contact pins will not line up right and potentially cause further issues. Check the schematic and see if it lists the type of connector and do a search by that. As for why HDMI does not work, it is always possible that there are further short circuits on the various display circuitry. You can only check it by starting your repairs with the known failed components. Order twice as many parts as you think you will need.

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I updated my post thx

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that switch could work. The screw is okay the way it is placed won't bother the board. Remember that you still have the short circuit on your LVDS connector.

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Ah ... but normally, The metalic piece comes between the mobo and the screw....so it doesnt have consequences.

I searched on the web but I dont find a place where they sell LVDS connector...do you know where can I have one of those. The mine is one that have a tightener.

Visually it just the plastic that melt a little bit. I dont see any connector that touch together or smthg

I added a picture to my post.

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Hello,

Have the same probleme with the power button of my LENOVO LEGION Y520-15IKBN

I open it and here how is the power button on the mother board :

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There clearly a missing part that I found on the speaker after my inspection :

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And here zoomed :

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I put the part back at it’s place :

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and put a big piece of capton on it :

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Now, the power button is fully operational.

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You are a champ, Pascal. Just had one come in with this same issue. Like yours, the part was stuck to the speaker. Ended up being a very quick fix thank to your help.

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oku ytr will be eternally grateful.
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