I said the power consumption occurs with just plain vanilla factory-made board without any external components.

No, you didn't. And, even a factory made board can be full of mistakes...

I asked my friend who did a few projects like that and he says power consumption up to 0.5A is typical for such boards... should I trust him?

Well, trust and confidence is the basis of true friendship. But why not stop excessive guessing and asking friends, if a simple measurement can totally clearify the situation???

Measure the voltage drop across R21 (1R6) with a serious and trustworthy DC millivolt meter. Supply current to analog section of your board is flowing through this resistor. This current 'Ia' can be calculated by

Ia = U21 / R21

where U21 is the voltage drop across R21.

Total supply current can be measured by the help of a simple 1R 1/4W resistor which has to be inserted between your mysterious power supply unit and power supply terminal of board:

Connect 0V of your power supply unit to terminal J6-1 or J6-3 of board. Connect +9V of your power supply unit to one end of 1R resistor. Connect the other end of this 1R resistor to terminal J6-2 of board (goes to anode of D3).

Total supply current 'It' of whole board can be calculated by:

It = Ux / 1R

where Ux is the voltage drop measured across this 1R resistor.

In combination with the supply current analysis, kind Mr. Karas made for you, you can find out whether something is wrong, or not.

Kai