Laptop Question
Hello,
I'm working on a Lenovo T460 that has been having trouble charging as of late. Its worked well since I've owned it for a few years. When I went to use it the other day it was dead and wouldn't turn on (was sitting on an Anker 65W GaN charger). After some fiddling with the charger I got it to turn on and start charging, but seemed like the charger was not working as it should (took a few plug and unplug cycles to get it to start charging).
A day later it was dead again and wouldn't boot/charge no matter what I did. No lights or anything when I plugged in the charger. Later in the day, I hit the power button not expecting anything and it booted to my surprise. As soon as it booted, it shut down for low batt. However, this indicated to me that it can run on battery, just not DC input power.
That lead me to believe the issue was on the input power circuit. I opened the bottom and found some schematics on this site (below). Being a mechanical engineer I'm not too familiar with board work, but I was able to measure an open circuit across the PF1 fuse right after the DC power in connection on the board. I ordered a replacement from Mouser and swapped it out on the board.
When I plugged it in everything was good. It booted and was charging the battery - Awesome! This was on the 65W Lenovo charger it came with. To check I moved it over to the Anker charger it was plugged into previously and it wouldn't charge. I then tried another 45W Lenovo charger I had used previously and it wouldn't charge on that. I also tried a 12v Lenovo charger I've used many time and also got nothing. Moving it back to the 65W Lenovo it immediately recognized the charger and started charging.
After tinkering with it more I've come to realize all the chargers will work if I plug them in when the computer is fully shut down or when I use a pin to press the power reset button on the bottom cover. At that point I can boot the computer and the charger will continue to work until I unplug it and re-install it. Then it will run on batteries until I shut it down.
Measuring the DC power at the PF1 fuse when the charger is plugged in and not working shows all sorts of erratic readings like the voltage is jumping around (I don't have a scope so just looking at the multi meter). When I shut it down or press the reset button the charger output immediately goes to ~20.4V and things start charging. This is on multiple of the chargers that are no longer working unless I shut things down.
Since it wasn't doing this before that fuse blew I am thinking there is something else that is failing in the circuit, but not sure where to start. I'm wondering if maybe the chargers are sensing an over current when plugged in and somehow plugging them in when the computer is off is just enough to stop them from tripping and then once they are plugged in there is no surge or inrush so you can boot and use them.
Any suggestions on how to go about troubleshooting it? Is there a way to open the .tvw file on a Mac? My windows machine is the one having issues.
Boardview: https://www.badcaps.net/forum/showth...37#post1238537
Hello,
I'm working on a Lenovo T460 that has been having trouble charging as of late. Its worked well since I've owned it for a few years. When I went to use it the other day it was dead and wouldn't turn on (was sitting on an Anker 65W GaN charger). After some fiddling with the charger I got it to turn on and start charging, but seemed like the charger was not working as it should (took a few plug and unplug cycles to get it to start charging).
A day later it was dead again and wouldn't boot/charge no matter what I did. No lights or anything when I plugged in the charger. Later in the day, I hit the power button not expecting anything and it booted to my surprise. As soon as it booted, it shut down for low batt. However, this indicated to me that it can run on battery, just not DC input power.
That lead me to believe the issue was on the input power circuit. I opened the bottom and found some schematics on this site (below). Being a mechanical engineer I'm not too familiar with board work, but I was able to measure an open circuit across the PF1 fuse right after the DC power in connection on the board. I ordered a replacement from Mouser and swapped it out on the board.
When I plugged it in everything was good. It booted and was charging the battery - Awesome! This was on the 65W Lenovo charger it came with. To check I moved it over to the Anker charger it was plugged into previously and it wouldn't charge. I then tried another 45W Lenovo charger I had used previously and it wouldn't charge on that. I also tried a 12v Lenovo charger I've used many time and also got nothing. Moving it back to the 65W Lenovo it immediately recognized the charger and started charging.
After tinkering with it more I've come to realize all the chargers will work if I plug them in when the computer is fully shut down or when I use a pin to press the power reset button on the bottom cover. At that point I can boot the computer and the charger will continue to work until I unplug it and re-install it. Then it will run on batteries until I shut it down.
Measuring the DC power at the PF1 fuse when the charger is plugged in and not working shows all sorts of erratic readings like the voltage is jumping around (I don't have a scope so just looking at the multi meter). When I shut it down or press the reset button the charger output immediately goes to ~20.4V and things start charging. This is on multiple of the chargers that are no longer working unless I shut things down.
Since it wasn't doing this before that fuse blew I am thinking there is something else that is failing in the circuit, but not sure where to start. I'm wondering if maybe the chargers are sensing an over current when plugged in and somehow plugging them in when the computer is off is just enough to stop them from tripping and then once they are plugged in there is no surge or inrush so you can boot and use them.
Any suggestions on how to go about troubleshooting it? Is there a way to open the .tvw file on a Mac? My windows machine is the one having issues.
Boardview: https://www.badcaps.net/forum/showth...37#post1238537
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