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Help identifying a chip on HP Omen motherboard

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    #21
    Re: Help identifying a chip on HP Omen motherboard

    Originally posted by R_J View Post
    Use your multimeter in diode test, with one probe on the base then with the other probe check emitter then collector should read around .6xx if not reverse the probes and check again, depending on which probe is on the base should determine the polarity.
    Based on picture 1, the base would be on the left, emitter on the right, collector by itself at the top.
    If the new transistor checks like the one on the new MB, you could likely solder it in place even though the leads don't quite match the pads you should be able to solder it on to try it.
    On the new transistor you see in the picture, the one that's slightly larger......black lead on base (left leg) and red lead on right leg, I get a solid 0.690. Black on base and red on right leg, I get OL. Black on base and red on top leg, I get 0.690. Red on base and Black on top leg, I get OL.

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      #22
      Re: Help identifying a chip on HP Omen motherboard

      Originally posted by R_J View Post
      The old chip will be bad, likely shorted if it burnt like in the picture
      Yeah, I hope it's bad, because otherwise I have more issues than just it. I just thought you might be able to tell if the polarity is the same as the new chips I ordered. If not, I'll open up the laptop. Was just trying to avoid it, because the more times you take them apart, the weaker the plastics get. The sloppier everything gets. Eventually becomes "loose" feeling.

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        #23
        Re: Help identifying a chip on HP Omen motherboard

        We know the BC856 is a PNP so with the Black lead on the base and the Red to the other two and getting a reading of .690 is how an unknown transistor would check.
        An NPN would check in a similar way but with the leads reversed.
        You originally thought it could be a mosfet, Do you know what the component does in the circuit? is it used to switch the battery voltage? if it is used as a switch it IS likely a mosfet.
        Last edited by R_J; 12-03-2019, 07:04 PM.

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          #24
          Re: Help identifying a chip on HP Omen motherboard

          Originally posted by R_J View Post
          We know the BC856 is a PNP so with the Black lead on the base and the Red to the other two and getting a reading of .690 is how an unknown transistor would check.
          An NPN would check in a similar way but with the leads reversed.
          You originally thought it could be a mosfet, Do you know what the component does in the circuit? is it used to switch the battery voltage? if it is used as a switch it IS likely a mosfet.
          Unfortunately I don't know what it does, because I finally gave up looking for a schematic. And to be honest, even if I found one I would need help interpreting it. I'm new to chip level knowledge and it's very overwhelming really. I kinda feel like if I wanted to learn enough to actually know anything, I should have started before age 46...lol. I did find some great (I think) links that are supposed to be very helpful in finding different components, but it's like reading a da Vinci prophecy. He wrote left-handed and backwards so others wouldn't know what he was writing. That whole "burned at the stake" punishment they had going on back then wasn't pretty! Oh and they are BC856,215's if that makes a difference. Thanks again!
          Last edited by apache23; 12-03-2019, 09:44 PM.

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            #25
            Re: Help identifying a chip on HP Omen motherboard

            Originally posted by jasko_jacker View Post
            As they have already said, without knowing the model or card or notebook it is not easy to identify the part. All the components that
            they start with Q, usually they are transistors but not always
            With 3D the most common component is MMBTA44
            MMBTA44 is 3.0mm x 1.4mm, which is the same dimensions as the BC856 chip that is shown in the 2nd picture and is too big.

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              #26
              Re: Help identifying a chip on HP Omen motherboard

              I found a couple more possibilities. These are closer to the size of the burnt one, if not the same size. The one in the 2nd pic that is too big is 3.0mm x 1.4mm. I found 2 diodes and 1 transistor. The 2 diodes both measure 2.0mm x 1.25mm and the transistor is 2.2mm x 1.25mm. Here are the datasheets for the three I found.
              Attached Files
              Last edited by apache23; 12-04-2019, 07:52 AM.

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                #27
                Re: Help identifying a chip on HP Omen motherboard

                I found out another piece of important info. I enlarged the chip from my new motherboard (same chip I need in good condition) and determined that the width of the chip is greater than 1/2 the length. On my TV, the width of the chip is 4 1/4" and the length is 7 3/4". This means that the length is approximately 1.8 x width. The chips in the link below all or most have this same 1.8 x width scaling. https://www.rohm.com/products/transi...ageEita=SC-75A

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                  #28
                  Re: Help identifying a chip on HP Omen motherboard

                  I tested the good chip on my new mother board and only got 2 readings other than OL trying every combination of leads to legs. The 2 readings were both 0.264v and they were both with the black lead on the leg that's by itself, then touching either of the 2 other legs. Does this mean it could be something other than a reansistor or just that the chip needs to be removed to test? The board has had no power applied to it for several days.

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                    #29
                    Re: Help identifying a chip on HP Omen motherboard

                    Can you desolder that part and take another photo so we can see where it goes,it looks like one trace goes to the battery connection.
                    All donations to badcaps are welcome, click on this link to donate. Thanks to all supporters

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                      #30
                      Re: Help identifying a chip on HP Omen motherboard

                      Originally posted by SMDFlea View Post
                      Can you desolder that part and take another photo so we can see where it goes,it looks like one trace goes to the battery connection.
                      Absolutely. I'm waiting for my new smaller, pointed tip to come. Should be arriving today. I don't have expensive equipment, just a Weller gun and some quick chip, solder sucker and a few different types of solder and flux. So I want to make sure to use this new, tiny tip that's coming. Until then, I can offer only this pic that's a little closer to that area. Sure looks like it's going to the battery connector, agree 100%.
                      Attached Files

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