Help fixing W520

[rdchinoy]

My laptop is not powering on.
History
I have been using it without a bat for 2 years never had any problems.
THe kyeboard was acting up. After replacing it 3 times in 2 years I just opted for an external wireless keyboard and mouse.
I setup the Bios to power on with a/c attach. Sometimes it would not power on. In such cases I would disconnect the power no bat re-attach the power press the power button and it would power up.

Now nothing I do gets it to power up. My keyboard which I only used the power button for the ribbon tore.
I have downladed the PDF and Board view for the laptop and plan to strip the board and try to repair it.

But before I do this. I had some questions.

1. How do I stress test my power brick. It puts out 20 Volts. But on the board from what I can access I am only seeing. 18 volts.
I need to see if my brick is actually capable of putting out 8.5 Amps as per what is printed on it. I would like to load it to about 5 Amps and see if it still puts out 20 Volts.

2. On the cover of the laptop display are 3 LEDS. When I plug in the cable. The bat ico in green blinks 3 times after that nothing. Where can I find the blink codes or what this 3 blinks mean. I hear its very common on Lenov laptops. Forums are filled with people reporting this but no answer. They even have a nick name for it the 3 blinks of death.

3. Does anybody have a picture which shows all the fuses on the mother board or a quick way to find them in board view.

4. Everybody keeps telling me its a bad cap. But there are no caps I can see on the board. All I see are SMD Caps.
Are there any popular failure caps to chk. Can I chk the caps in circuit ?. I have a tweezer that is a multimeter that does voltage, diodes, resistance, caps. But in circuit ?. Im not sure.

5. Is there a humidity sensor on this mother board ?. Cause I noticed when humidity is high it does not power on. But if I run the a/c and bring the humidity down to 10% it powers up. (I have cleaned what I could on the mother board with ISO and a brush. (What I could access without stripping it down).

As of right now I have ordered a new keyboard. Because I need to at least power it on. (Though I am pretty sure there is a way to power it on without a power button or keyboard. I saw a video a long time ago where a guy working on a board got it to power on by shorting 2 pins. Which 2 I dont remember. (My keyboard ribon cable is torn so I cant lift the power button and short the pins there.

I suspect its either the power brick or a blown fuse or a weak cap. Sometime if I leave it for a few days and power it on. It powers on.

Ps: Pin3 and ground may trigger the start of power on. On the keyboard ribon.

[SAIYAN48]

I killed the keyboard on my R500. Unplog the CMOS battery, give it A/C and it should come right on.

[mikemex]

Also, keep in mind that old hardware physically degrades. It's inevitable that it will start failing at some point, just due to age.

[axur-delmeria]

Also, keep in mind that old hardware physically degrades. It's inevitable that it will start failing at some point, just due to age.

Given that the W520 is already 11 years old at this point, anything can happen.

[RealBlackStuff]

Ps: Pin3 and ground may trigger the start of power on. On the keyboard ribon.

On the motherboard's keyboard connector it is pin 19 and ground to power on.

[rdchinoy]

I killed the keyboard on my R500. Unplog the CMOS battery, give it A/C and it should come right on.

This has worked for me in the past. You need to leave it unplugged for at least 30 min.
Problem is I have setup the power option in Bios to power on when it detects a/c plugged in.
I am scared to loose this setting. But if after the new keyboard arrives. It still does not power on I will give it one last shot.

I need to understand why the 3 blinks on the leds of the laptop cover what does it mean ?. And after that nothing why ?.
I suspect the super IO chip.
Maybe its not powering up because no keyboard. Lets see replacement keyboard should be here soon.

A picture of all the fuses would be a big help.
Worst case I strip it down and start from the power in socket and take it from there. Already I am seeing that power rail is only 18 volts but at the connector I am geting 19.5 volts. It could just be dust and drive causing some kind of short. This laptop has seen a lot of abuse on race tracks across India. And extremes in Temp. Though since I retired it has been on my desk for 5 years.

[rdchinoy]

I had a look at the keyboard connector it has two rows off 10 pins each. The pins are too close to each other for me to try and short it.

About locating the fuses any part with a F in front of it is a fuse. R is for Resistor which you can chk with the meter, c is for the caps. Dont think these can be checked in circuit other than for a short. And F is for fuse.
So I hope that doing a search for F in board view will pop up all the fuses.

[rdchinoy]

Answering my own question.
Open the top silk screen and bottom silk screen. Then just Look for F that will show you all the fuses on the mother board.
I am going to try and attach the files here. Not sure where I got them from But have been hunting for schematics and board view files for days. So far I have not been able to find anything like the s/w I used when I repaired my phone.

That had a drawing of the board. Every component. You clicked on a wire and it traced that signal across the circuit.

Anyway this should help you locate parts fast. Like all the fuses. Or all the caps.
https://drive.google.com/drive/folders/ ... sp=sharing

[rdchinoy]

Thanks guys I got it working.
I had a USB wireless keyboard attached.
I tried shorting pin 19 and ground. 3 and 6. And a few other options nothing worked.
Today my new keyboard arrived plugged it in and it fired up.
Im not sure what fixed it. They keyboard or all the things I did in between.
Like washing out the board in iso. Reflowing the Ram connector to the board connections.
Used an eraser to clean up all contacts and connectors on Ram chips.

There seems to be something on the keyboards that prevent these machines from powering on.
Though I could swear I have seen videos of people powering on these boards without a keyboard.
Go figure. This was a cheap china clone. Keyboard. But it worked. Brand name lappy.
Anyway its good to have my ole gal and companion off over 10 years back up and running.

[axur-delmeria]

Good to hear you got it working.

If you had a dock, turning on the W520 without a keyboard would've been much easier.

That said, I do remember managing to turn on an X series thinkpad (either X61 or X220) without a keyboard using a short length of solid wire, maybe from a LAN cable. Since I wasn't sure where pin 19 is located, I had one end of the wire touching a grounding point on the system board, then ran the other end along the soldered legs of the keyboard connector. I quickly withdraw the wire once the laptop turns on, minimizing the chance of shorting two signal pins.

[rdchinoy]

As I had a new keyboard on its way didn't want to risk anything. But thats a good idea.
I think most of these problems are keyboard related. i.e. either power is not working. Or its stuck.
This maybe my all time fav laptop. Owned it for over 11 years. But the keyboard design sucks. I have changed 5 keyboards so far. Agreed after the 2nd one I switched to china made. And after the last one I switched to USB. Wireless.
I think a good idea for anybody having this problem is to just pull the keyboard and try to start it by shorting the pin 19 and ground. Like you did.
Im not sure it would work on a W520 though as I never tried it.