Need some help identifying a chip on HP Omen motherboard

Thread Starter

apache23

Joined Dec 5, 2019
9
Need help identifying the chip in the pic so I can order one. This is for an HP Omen 15-5113dx laptop. The motherboard part# is 806343-001. Other part#'s that are for same style board: 806344-001, 806345-001, 812215-001, 812215-501, 812215-601, 806344-501, 806344-601, 812217-001, 812217-501, 812217-601. The chip looks to have "3D" and "U5 or maybe Q5" printed on it. The first pic is my bad chip and next to it is a BC856 transistor I bought that is a little too big. The 2nd pic is of a good motherboard and the same chip that I need. The 3rd pic is just to show where the chip is located on the mobo and various connectors. My knowledge of chip level electronics is slim...lol. I can solder pretty good and have fixed many motherboards, but this is the first part I have been unable to identify. I have posted in other forums with no luck so far and it is going on 2 weeks with the problem. Some other info: I have no accurate way of measuring the chip, but it must be approx. 2.0-2.2mm x 1.2-1.4mm comparing it to the BC856 in the pic next to it. Also, I enlarged the pic on my TV and the length is less than 2x the width. Any help would be appreciated and thank you!
 

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Thread Starter

apache23

Joined Dec 5, 2019
9
Hi Apache23. An SMT transistor with a 3D marking is MMBTA44. Hope this helps.
Thanks for the reply peterdeco. I have looked at MMBTA44, as it was a suggestion from someone on another site, but determined it was too big. It is 2.70-3.04mm x 1.20-1.60mm. We thought it more resembled SC-70 or SC-85 perhaps? These are closer to the same overall size, but comparing them by size is the extent of what I can do. I also tested the bad chip on the board and got the following results. Not sure if it helps, but here it is : With the red lead on the base (leg on left) and black on the leg on the right, I get 0.340 and it started dropping and kept dropping slowly. It was at 0.251 when I removed the lead and still dropping. Red on base and black on top leg, I get 0.260, no dropping voltage. With black lead on base and red on right leg, I get .480, then it went up slowly to 0.504, then dropped slowly and kept dropping till it seemed to stop at 0.491....but after about 15 seconds, it dropped to 0.490. After about 25 more seconds, it dropped to 0.489 and that's when I removed the lead. Red lead on base and black on right leg, I get 0.340 and it dropped fast to 0.315...then slowly to 0.308 and seemed to rest there for 12 seconds, then dropped to 0.307 and I removed the lead. Red lead on base and black on top leg, I get 0.455. Also, I have looked for the schematic for 2 weeks, with no luck. Thanks!
 

peterdeco

Joined Oct 8, 2019
58
Hi apache23. An SC70 comes up as a regulator. Your device is designated Q250 something. Transistors are almost universally designated with a Q. The MMBTA44 is in a SOT-23 package and looks like your part. And your right, I can't find the schematic anywhere - yet.
 

Thread Starter

apache23

Joined Dec 5, 2019
9
Hi apache23. An SC70 comes up as a regulator. Your device is designated Q250 something. Transistors are almost universally designated with a Q. The MMBTA44 is in a SOT-23 package and looks like your part. And your right, I can't find the schematic anywhere - yet.
The MMBTA44 is the same size as the one I bought (BC856) that is in the picture next to the blown one. So if I get it, should I just put a couple larger blobs of solder on the legs to get them to connect? Thanks againg for helping and btw, I pretty much look up things on the internet for a living and I can't find that schematic, so if you find it, you're the Man!...lol.
 

Thread Starter

apache23

Joined Dec 5, 2019
9
Hi apache23. An SC70 comes up as a regulator. Your device is designated Q250 something. Transistors are almost universally designated with a Q. The MMBTA44 is in a SOT-23 package and looks like your part. And your right, I can't find the schematic anywhere - yet.
Oh and btw, it's Q2501 if that helps.
 

Thread Starter

apache23

Joined Dec 5, 2019
9
Hi apache23. An SC70 comes up as a regulator. Your device is designated Q250 something. Transistors are almost universally designated with a Q. The MMBTA44 is in a SOT-23 package and looks like your part. And your right, I can't find the schematic anywhere - yet.
I just tried checking the chip on my good motherboard with battery unhooked and the ONLY 2 ways I get a reading besides OL, is when the black lead is on the leg that's by itself. Then touching either of the 2 other legs, I get 0.264 on both. Apparently I have to take it off to check it maybe?
 
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