Hi again,

I still have not found anything suspicious yet, I will try to learn more and follow the [URL="https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/80414-laptop-battery-charging-circuit"]charging circuit troubleshooting guide [/URL]once more to hopefully catch something.

I am still puzzled in what could be the reason for the battery charging to still work, and that it actually seems to boot for a few seconds (keyboard lights up for 3-5 seconds and display even flashes...

I measured the resistance to ground of all inductors I could find (at least the bigger grey ones). Not sure which one is PLB1.

None seem to indicate a short, I get quite a big range of values however: ~7.5 ohm, ~30 ohm, ~500 ohm, or others increasing forever (from k to M to ...) and confusing my cheap multimeter.

I am sorry, I just redid the measurements to confirm and make sure: PIN 6 shows 3.28V and not 0.00V as previously stated.

Just in case, I also did the DIODE mode measurements (with red probe on ground) with charger and battery disconnected:
PIN 5 => 0.60V
PIN 6 => 0.55V...

I measured several times and get this:

PIN 1 => 8.68V
PIN 2 => 8.68V
PIN 3 => 0.00V
PIN 4 => 0.29V
PIN 5 => 3.28V
PIN 6 => 0.00V
PIN 7 => 0.00V
PIN 8 => 0.00V

Detail: Measured with the charger cable unplugged

I understand it corresponds to this if I have the right schematics:

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Hi all,

I'm quite new to this and trying to learn by help a friend with his SF514-52T that stopped booting after battery was replaced. I suspected the battery was bad but the problem persisted when putting back the original one (which is was still working although with reduced capacity).

When pressing the power-on button the symptoms are:
- Keyboard backlight and blue power LED turn on for about 5-7 seconds, and then flash off-on in ~3 seconds cycles (reboot loop).
- Display does not seem to turn on, although it sometimes seems to flash in between reboots....

Hey this is Noc from Denmark. I have basic electronics knowledge but have not used that since university.

Looking for some advice to fix a few laptops lying around, and hopefully learn a thing or two!