The meaning of those letters on the PCB

Cx:a non-polar capacitor, power input capacitance interference 

IC:integrated circuit module 

Ux:an IC (Integrated Circuit Component)

Tx:the test point (factory test) 

Spk1:Speaker (buzzer, speaker) 

Qx:a transistor 

CEx-Electrolytic Capacitor,

CNx-Capacitor,

RNx-Exclusion,

CONx-Connector,

Dx-Diode,

Lx-Inductor/ Bead,

LEDx-LED,

Xx-Crystal. 

RTH(Thermistor) 

CY(Y capacitor: high-voltage ceramic capacitors, safety regulations) 

CX(X capacitor: high-voltage film capacitors, safety regulations) 

D(diode) 

W:regulator 

K:switch class 

Y:crystal 

R117:Motherboard resistance, number 17. 

T101:Transformer on the motherboard. 

SW102:switch 

LED101:light-emitting diode 

LAMP:(indicator) light 

Q104(E, B, C): Transistor, E: Emitter, B: Base, C: Collector