I am not electrically savvy person but I have general idea of what some things are and what they do. I have this nice computer video card that has a broken transistor on the back side and is not working. The reading on it is K1P Z4. I did some googling and some online catalogue searches but that didn't turn anything. There are 2 transistors next to each other and one is broken in half (appears someone has dropped something on top of it) and they are the same size. The broken one is unreadable in the middle but beginning and the Z4 end is same as the other transistor so I assume they are the same. I am hoping any of you can help me identifying it and get a replacement.picture taken with a magnifying glassenter image description here

  • \$\begingroup\$ K is short form for 2SK which is japanese \$\endgroup\$
    – Autistic
    Nov 13, 2015 at 5:14
  • 1
    \$\begingroup\$ @autistic : very often true, but a 2SK1 would be a very old transistor, making a SOT23 package unlikely! In TO92, TO220 etc it's common to see part number shortening, but for tiny packages marking bears no obvious relationship to part number. \$\endgroup\$
    – user16324
    Nov 15, 2015 at 10:43

1 Answer 1


Googling SOT23 marking K1P the first hit links to the MMBT2222 datasheet which contains the following text ( on page 2 in a section called"Marking Information" ).

K1P = Product Type Marking Code
YM = Date Code Marking

and a further table decoding the "ym" date code. The table only goes up to W (=2009) but it's reasonable to guess that Z4 means April 2012.

Seems pretty conclusive to me.
(SOT23 is an industry standard packaging which looks exactly like those in the photo)

And it's a common type of NPN switching transistor so it should be very easy to find a replacement or a suitable substitute.

  • \$\begingroup\$ Thank you Brian. Guess I was googling the whole thing that's why didn't show any as that's a manufacturing date. Now I even found updated spec sheet online and ordered replacements. Thing is there were 2 choices,1 is 600ma continuous current and other is 1A. When they arrive I should try a 600ma first correct? \$\endgroup\$ Nov 15, 2015 at 17:47
  • 2
    \$\begingroup\$ Video card worked after putting 1000ma transistor. Took a bit to solder (it weighs as much as grain of sand) Thank you both for your help. \$\endgroup\$ Nov 19, 2015 at 15:09
  • \$\begingroup\$ @VeskoVasilev: FYI, the code can be found/confirmed in this codebook, p. 282. The only possible clash for that one is a BCW71 by Philips which is rather too old and the "p" would indeed be lowercase for that one (confirmed with the datasheet). \$\endgroup\$
    – Fizz
    Nov 20, 2015 at 6:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.