Identify parts in a circuit diagram?

How do I identify parts in a circuit diagram?

E.g. this one?

https://www.scribd.com/doc/207782153/Dell-2407-WFP-Power-Supply-Rev-A11-Schematic-Diagram

What is e.g. Q653? It is a SMD transistor of some sort just from the look of it, but what kind? I need to know exactly.

Is this circuit diagram simply missing some mapping between local identifiers used in the circuit diagram and what those parts correspond to, or am I supposed to be able to figure it out some other way?

2N7002

halleffector said:

Is this circuit diagram simply missing some mapping between local identifiers used in the circuit diagram and what those parts correspond to, or am I supposed to be able to figure it out some other way?

Click to expand...

Can you give an example? Here is Q653 for example:


It appears the information you need is there.