02-09-2015 06:36 AM
Thank you for suggestion, but I got 10x AO4423 mosfet in ebay. Im tried to measure the resistance of mosfet without dissasebling laptop, so i got infinitive resistance (like when multimeter is dont touch nothing) so it is the sign of dead mosfet ?
04-20-2015 08:45 PM
Hello! I'm really inexpert in open and fixing computers in general; I have the same problem with my Y400 and I was wondering if anyone try the solution with this particular laptop? or maybe can someone tell me the model of my charging controller mosfet (or how to serch for it), or the equivalent I need to replace in my y400. Thanks a lot
04-25-2015 05:30 PM
Hi Jansilp, I'm having the exactly same issue here on my y580 and now I'm attempting to replace the dead mosfet.
Just a little question, that do I need to reformat the hardisk and reinstall windows after replacing the dead mosfet?
Or I don't have to format and everything will works back as usual right after I replace the dead mosfet with a new similar one?
07-02-2015 09:34 PM
First of all, I can't thank enough the OP for solving this absurd failure. Many, many thanks.. really.
Second, after a 250 USD repair my Y500 is operational again. Now the battery is charging correctly , nevertheless it has a minor glitch that I think I can live with.
In my case, not only 1 mosfet was dead, but several others behind it. I can't elaborate more, but that is what the technician said. Anyway, I have always held the IBM/Thinkpad in a very high regard.. My very first computer was a Model 25 PS/2... and up to date I have only owned IBM/Lenovo computers with the exception of some VAIO (and a Mac). Let me put it this way this is my first repair I have done to a computer. Unbelievable reliability from the Lenovo guys.. amazing really. BUT.. what has been done/decided regarding that battery calibrator it is just a really low blow. Completely messed up.. shouldn't by any means that app be still there in our computers. I don't care if its still under or without warranty.. its reckless on how this issue is being handled. If there's a slight chance that the app messes up the mottherboards since 2012-13.. just wipe it off.. that simple. I can understand that computers fail.. I'm perfectly fine with that, but to ignore that an app can kill a motherboard AND fail to communicate to its owners just leaves me speechless.
I'm still buying the Yoga one of these days, but guys really... come on...do the right thing and if you have to take it on the chin, so be it, but you will be held in a much better regard than when failing to accept the situation.
10-18-2015 02:29 AM - edited 10-18-2015 02:38 AM
Just a note. The y510p has this issue as well. I just replaced the mosfet on my motherboard after a year of this failure, although I got aroung it by lowering the current sense shunt resistance in the psu so it wouldn't go into ocp mode for the second it draws the spike of current. Unfortunately, after prolonged use, this killed the brick so I figured I'd track down the root of the issue. Guess what? Shorted mosfet.
Coming from an EE background, the mosfet they are using seems entirely inadequite. Only 30v in an input that can see high esd spikes and runs at 20 nominal? Yikes. (On second thought less so, beacuse it is also floating on top of battery voltage for more margin) Not to mention that at the ~10Amps my computer can draw, the 8mohm fet they use will dissipate close to a watt right next to other hot stuff, which I think is probably what caused mine to fail, as I don't even have the energy management software installed to kill it that way.
Pic of fet:
12-30-2015 11:29 PM
Awesome, thanks a lot! I bought the recomended MOFSET from Digi-Key, opened my laptop with the help of some you tube tutos, got the new mofset welded by a friend and it solved the issue. Blessings!
01-07-2016 07:26 PM
Hi all - - I ordered FDS6681ZCT-ND from digikey, as I have the same issue w/ my y580.
The mosfet they sent is TINY - like REALLY tiny... unless I got the wrong thing - I just don't see how its possible at all to solder by hand. The whole piece is like 1/4" in size, right, with tiny very close pins? Can you tell me if I got the wrong part - http://www.digikey.com/product-detail/en/FDS6681Z/FDS6681ZCT-ND/1626210
01-07-2016 09:26 PM
It is very tiny but someone with the know-how should be able to do it. As I said I gave to an electrical guy who did it within 10 mn. In addition there was an even smaller diode in the bottom of the sachet (0.2mm? looked like dust to me) and he managed to weld that one as well.