Hosein Asadolahi
Staff member
There are some MOSFETs on some boards, similar to the picture below, which are so similar to single MOSFETs. In fact they are single High and Low MOSFETs that come in one package.
How can you distinguish a single MOSFET from a Dual MOSFET before removing them from boards?
And in case any of the internal MOSFETs gets shorted, how do you know that part in the Dual MOSFET is shorted through the board?
How is testing this type of MOSFET out of boards?
View attachment 42872
As you can see in the picture below, Single and Dual MOSFETs are quite similar in appearance and it is not so easy to distinguish them from each other, but due to experience in laptop repairing, if there is only one MOSFET next to each inductor in Core block, we can realize that it is a Dual MOSFET. (Please note that, High and Low MOSFETs are placed on both sides in some boards and make sure Not to confuse them with Dual MOSFETs
)
Also, according to Dual MOSFET pins, pins 1 and 8 are Gate pins of High and Low MOSFETs and should not be connected to other pins.
And finally, the easiest way to detect is to refer to schematics and boardviews of laptops or datasheets of MOSFETs.
If each of the MOSFETs gets shorted, the process of testing is the same as testing single High and Low MOSFETs.
Let’s assume a High MOSFET is shorted. What you need to do in this case is to set your multimeter on Diode or Ohm mode and place one probe on the inductor and the other probe on B+, then you’ll realize the High MOSFET is shorted
And in case a Low MOSFET is shorted, you also need to set your multimeter on Diode or Ohm mode and place one probe on the inductor and the other probe on GND, and then you’ll realize the Low MOSFET is shorted (it needs to act like a Diode which needs to be connected on one way and shouldn’t be connected on the other way)
Testing MOSFETs outside the board is similar to when they are on boards and please not that Gate pins of MOSFETs shouldn’t be connected to either of the other pins.
View attachment 42873
View attachment 42874
Testing Dual MOSFETs:
In the video, we practically tested 2 Dual MOSFETs, one of which was working and the other one was problematic.
Thanks for reading the article to the end and watching the video
Enjoy
This video is dubbed into English!
FREE DOWNLOAD
How can you distinguish a single MOSFET from a Dual MOSFET before removing them from boards?
And in case any of the internal MOSFETs gets shorted, how do you know that part in the Dual MOSFET is shorted through the board?
How is testing this type of MOSFET out of boards?
View attachment 42872
As you can see in the picture below, Single and Dual MOSFETs are quite similar in appearance and it is not so easy to distinguish them from each other, but due to experience in laptop repairing, if there is only one MOSFET next to each inductor in Core block, we can realize that it is a Dual MOSFET. (Please note that, High and Low MOSFETs are placed on both sides in some boards and make sure Not to confuse them with Dual MOSFETs
)Also, according to Dual MOSFET pins, pins 1 and 8 are Gate pins of High and Low MOSFETs and should not be connected to other pins.
And finally, the easiest way to detect is to refer to schematics and boardviews of laptops or datasheets of MOSFETs.
If each of the MOSFETs gets shorted, the process of testing is the same as testing single High and Low MOSFETs.
Let’s assume a High MOSFET is shorted. What you need to do in this case is to set your multimeter on Diode or Ohm mode and place one probe on the inductor and the other probe on B+, then you’ll realize the High MOSFET is shorted
And in case a Low MOSFET is shorted, you also need to set your multimeter on Diode or Ohm mode and place one probe on the inductor and the other probe on GND, and then you’ll realize the Low MOSFET is shorted (it needs to act like a Diode which needs to be connected on one way and shouldn’t be connected on the other way)
Testing MOSFETs outside the board is similar to when they are on boards and please not that Gate pins of MOSFETs shouldn’t be connected to either of the other pins.
View attachment 42873
View attachment 42874
Testing Dual MOSFETs:
In the video, we practically tested 2 Dual MOSFETs, one of which was working and the other one was problematic.
Thanks for reading the article to the end and watching the video
Enjoy
This video is dubbed into English!
FREE DOWNLOAD
Last edited by a moderator: