Motherboard what the letters represent

1. L---- inductance. Inductance coil
2. C---- capacitors.
3. BC-- Chip Capacitors
4. R---- Resistors
5.9231-chip pulse-width -----

6.74 ----- it is the circuit board next to the South Bridge
7.PQ---- FET
8.VT, Q, V ---- 3 tubes
9.VD, D --- 2 tubes
10.RN---- exclusion
11. ZD ---- regulator diode
12.W----- potentiometer
13.IC-- Regulators Block
14.IC, N, U ---- IC
15.X, Y, G, Z ---- Crystal
16.S----- Switch
17.CM---- frequency generator (usually next to the crystal 14.31818)