I tried to identify the component marked with "t 30" the SOT23 package. I looked for the "t" of "7" symbol in this list
and also tried smd marking search engine but couldn't find it.
I was looking after the sign, but I could not find this item. But to my eye, it will be NPN or N-MOSFET transistor. The bottom right foot looks like it was connected to GND. The lower left leg as if it received a control signal (narrow path). In contrast, the upper leg as if it had a connected load (wider path). It looks like the NPN or N-MOSFET transistor as a key function.