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This is one of my older laptops, which had a broken screen but everything else was fine. i recently took it apart for fun and was very careful reinstalling everything, however now it does not boot into bios or even POST, there is no led on the power button even.
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Hi @zelapid
Try a full power refresh and check if that allows the laptop to turn on and pass POST.
Here's the hardware maintenance manual for the laptop. Go to p.29 (35 of 62 pdf) and p.33 (39 of 62 pdf) to view the procedure to disconnect the battery and the coin cell battery respectively.
When the coin cell battery is out, measure its voltage. if it is <2.5V DC or if the battery is >4-5 years old, replace it. Search online for 5B10S34075 to find suppliers that suit you best.
If it still doesn't turn on, just verifying that when you previously took it apart, did you disconnect the main battery from the motherboard, before taking it further apart?
If not (or even if you did), then the schematics for the motherboard will be needed to find out what's wrong.
If the motherboard model number (printed on underside of motherboard) is S150IGL SVT MB 19705-1M 448.0JB02.001M or S150IGL SVT MB 19705-1M 448.0JB03.001M, then here's a download link for the schematics . Unfortunately you'll have to purchase it. I couldn't find a free download online. You may have better luck
Hopefully the battery was flat and not that there was still enough voltage in it to cause some damage when you were working on the motherboard.
There's always power somewhere on the board, even when the laptop is turned off. The power switch is not a power isolating switch. Its function is to signal the intentions of the user to the BIOS/OS e.g. turn on, wake up, force stop.
The schematics are the wiring diagram for the motherboard.
They show how the motherboard components are connected to each other, what type and value they are, (necessary if a component is damaged and you don't know what type/value it is), where the different voltage supplies that are needed e.g. 1.5V, 3.3V, 5V etc are derived from the charger/battery etc. Basically you can determine how it works electrically.
Try disconnecting the battery from the motherboard and connecting the charger and see if it turns on, using the charger only.
If still no good, no power LED when a charger is connected should be checked first because it is a basic function.
You may have start at the beginning and check if the DC-In jack is OK by proving that the 20V DC from the charger is actually getting to the motherboard through the DC in jack, either by using a voltmeter (with the charger connected) or an Ohmmeter (with no charger connected)
If the DC-In jack is OK then you will definitely need the schematics to find out why it is not indicating that the charger is connected.
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I tried the full power refresh, the coin cell battery was also around 2.77V so that was fine, however still no POST or power led even. When i previously took it apart i only took the heatsync and sdd out so i didn't uninstall the battery at that state since it was almost flat as well.
What will the schematics for the mobo show in solving the problem? i suspect its a BIOS thing due to no POST, but Lenovo only provides an exe file.
*2nd*
By power led i mean on the power button key when the laptop is on. The charging led next to the power input works fine, it was orange but turned to white after a while of charging.
So it is possible that just by disconnecting a ssd and WAN card that the bios chip could become corrupted with battery power i presume. I don't have any of the BIOS programmers currently so i tried finding BIOS dumps for the laptop online to flash via usb, but no luck currently.
I have found that FN + R + power does make the charge led turn orange, what i think is some type of bios recovery mode
Here are some download options for the BIOS bin file if the motherboard is a S150IGL SVT MB 19705-1M 448.0JB02.001M model.
This is what I found if it is a S150IGL SVT MB 19705-1M 448.0JB03.001M
Make sure that you get the correct one for the motherboard used in your laptop.
You will have to remove the motherboard as the model number is on the underside of the board.
I haven't had time to work on it lately, however as i was going to try it, the power LED suddenly worked and it booted and performed a disk repair. The problem must of been uninstalling the SSD with the battery plugged in.
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