Thank you Sarma vu3zmv for the answer.
I do not have such a diode on hand, but I soldered the current one and the measurement indicates that it is probably working.
I didn't mention it before but I have an additional built-in amplifier on MAX 9814 between VOL-H and VOL-M. When I remove it, I can't hear anything.
I'll order the LEDs and keep looking.