I wanted the emitter, and your markup shows 9.4V there.
Something is wrong in the 13.5V supply, either with something overloading the supply or a fault with the 14V zener diode (D4). Try measuring that voltage with the unit in each of its operating modes, including AM, FM, phono, and AUX.
(sudenly sounds relay's click and source led iluminates brigther but Voltage rises to 10VCD in Q25 collector and back to low voltage then rises to 13.9VCD, and back to low Voltage)
Q25 Collector Voltage
NORMAL MODE -------------------- MONITOR MODE
AM= 39.8 VCD ------------------------- AM= 40.0 VCD
FM= 40.0 VCD --------------------------- FM= 40.3 VCD
Phono= 39.8 VCD --------------------------- Phono= 40.0 VCD
Aux= 39.8 VCD --------------------------- Aux= 40.0 VCD
Q25 emiter Voltage
NORMAL MODE -------------------- MONITOR MODE
AM= 9.0 VCD ------------------------- AM= 9.4 VCD
FM= 9.4 VCD --------------------------- FM= 9.8 VCD
Phono= 9.0 VCD --------------------------- Phono= 9.4 VCD
Aux= 9.0 VCD --------------------------- Aux= 9.4 VCD
D4 Voltage (same node as Q25 base)
NORMAL MODE -------------------- MONITOR MODE
AM= 9.3 VCD ------------------------- AM= 9.6 VCD
FM= 9.7 VCD ---------------------------- FM= 10.2 VCD
Phono= 9.3 VCD ------------------------ Phono= 9.6 VCD
Aux= 9.3 VCD -------------------------- Aux= 9.6 VCD