Hi everyone,
I accidentally connected my PSU to my Lenovo IdeaPad 320-15IKB with the wrong polarity. Now, the laptop doesn't charge anymore.

When I connect the charger, the PC detects it but doesn't charge. The battery still works and powers the PC, but the laptop won't turn on without the battery. I tested the PSU with other computers, and it works fine. However, when connected to this laptop, it only draws 0.076A.

I can't see any burnt components, and everything looks fine. Based on my research, it seems like the MOSFET protection circuit might be damaged.

I'd like to repair the laptop myself, how should proceed?

Thanks in advance.

PS: I'm attaching the schematics I found

 

Look at sheet 53, This is the charge control. Find PQ311 and, nearby, a good ground point, usually a screw. Plug in charger, turn on and follow steps in diagram, then report back.

 

Hi Irving, thanks for your quick reply,
on PQ311 pin 5 I get 20V, on PQ311 pin 1 I get 0 and on PQ311/312 pin 4 I get 0 too.

 

What voltage is on resistor PR310 both sides?

 

Hmmm... 0v on pin 4 means the charge controller chip either isnt seeing VIN or is unable to start the charge pump that turns on PQ311 & 312. Put your multimeter on diode setting and check PQ311 pin 4 to pin1, both ways round, then same on PQ312. If thats short circuit then PQ311 and/or PQ312 probably need replacing.

 

What voltage is on resistor PR310 both sides?

I'm unable to locate the PR310 resistor, I'm attaching pictures so maybe you can help me find it (I apologize if the pictures are a bit blurry, but that's the best my phone can do).

Hmmm... 0v on pin 4 means the charge controller chip either isnt seeing VIN or is unable to start the charge pump that turns on PQ311 & 312. Put your multimeter on diode setting and check PQ311 pin 4 to pin1, both ways round, then same on PQ312. If thats short circuit then PQ311 and/or PQ312 probably need replacing.

From PQ311 pin 4 to pin 1 I measure a voltage drop of 0.038V and from PQ312 pin 4 to pin 1 I measure a voltage drop of 0.036V. The value is the same in both ways. Should I consider them shorted?

Thanks to everyone

 

From PQ311 pin 4 to pin 1 I measure a voltage drop of 0.038V and from PQ312 pin 4 to pin 1 I measure a voltage drop of 0.036V. The value is the same in both ways. Should I consider them shorted?

Thanks to everyone

I should have said to do that last measurement with the charger disconnected (so do so, just in case its different), but yup, that's the most likely answer... or at least PQ311 is. The next step is to remove PQ311 and confirm it is shorted, and recheck PQ312 (because PQ311 shorted could mask if PQ312 is, or not...). The easiest/safest way to do so is with a hot-air gun with a very small - 1 or 2mm - nozzle. set to 350-400degC. If you only have a soldering iron then you need some ChipQuick low-melt solder, a strip of solder-wick and lots of No-clean flux.

I'm unable to locate the PR310 resistor, I'm attaching pictures so maybe you can help me find it (I apologize if the pictures are a bit blurry, but that's the best my phone can do).

It'll be very close to PU301 and those MOSFETs.. DD's suggestion would provide additional confirmation that one or other or both of PQ311/PQ312 are blown.

Ah, its not labelled..Measure from pin 4 of PQ312 to pin 4 of PU301