I need to know if anyone can identify this transistor. Upon installing the card and powering it up, the smd located at q503 just went up in smoke. The only markings on this are 21e25. I have dug to find it's data sheet, but have hit a dead end. I am not sure what this smd does. Maybe voltage regulator? Thanks in advance. Oh, and yes the card was installed correctly. Something in this circuit gave up the ghost. The one I want to try is NX2301P215, just not sure if this is the right replacement. Is there anyone with expertise that could help me?

Great advise. Unfortunately the card is way out of warranty. I did do some probing with a dmm but only with the card powered down. Also, I do have an ocilloscope but have not attempted to use it in the circuit trace procedure. Being that this post is new, and the card rev version is from 2004. I am hoping maybe someone has had an issue with the card that has some basic knowledge of the circuit design and maybe get someone with this same card to get me some working voltage reading from q503's gds. I will let this post marinate. If all else fails I scrap the board, no big deal. The thrill of finding the fault and repairing it for me, out ways tossing the board. I am well aware these things are hit and miss to repair. Caps, just like a motherboard, seem to be what everyone repairs. Past that, the thing is scrap for most. On the flip side, my guess was also an n or p channel mosfet but these are all guesses. Obviosly it was the weekest link in what ever short happened. I will continue to study and cross any ic that i can find via shematic search off the the check list. Let's face it, these guys use their own coding for smd and some ic and this makes it near impossible to locate the part in question. Again thank you for your time.