The Meaning Of Those Letters On The PCB Board
Rx is a resistor. There are many resistors in the circuit diagram, which are listed by serial number, R1, R2. . .
Cx is a non-polar capacitor, anti-interference capacitor at the input of the power supply
IC integrated circuit module
Ux is an IC (Integrated Circuit Component)
Tx is the test point (for factory testing)
Spk1 is Speaker (buzzer, speaker)
Qx is a triode
CEx-electrolytic capacitor, CNx-discharge, RNx-exclusion, CONx-connector, Dx-Diode (diode), Lx-inductor/bead, LEDx-LED, Xx-crystal.
CY (Y capacitor: high voltage ceramic capacitor, safety)
CX (X capacitor: high voltage film capacitor, safety)
K switch class
Y crystal oscillator
R117: The resistance on the main board, serial number 17.
T101: Transformer on the main board.
LAMP: (indicator) light
Q104 (E, B, C): Transistor, E: Emitter, B: Base, C: Collector