The first reverberator present here is based on TDA1022, the most used BBD.
Reverberator adjustements for proper functionality
Before we connect the power supply, extract IC2 and IC3 from its base and adjust the potentiometers to middle position. On one of IC2 or IC3 entries connect a frequency-meter and/or oscilloscope. On oscilloscope monitor will be visualized the rectangular pulses with point to point amplitude equal to power supply voltage and a space factor of 1:1. The frequency of this pulses is adjusted with P3 between 3 and 18kHz. Check that voltage value on IC2 pin 5 is 7.5V dc.
Disconnect the power supply, reconnect IC2 and IC3 and reconnect the power supply. Connect the oscilloscope to IC1.3 pin 8 and adjust P1 and P2 to ground.
Apply a 200Hz, 1.5 Vrms sinusoidal signal at the reverberator input . Adjust SR1 untill you obtain the best sine wave on the oscilloscope. Apply a 200Hz, 1Vrms sinusoidal signal at reverberator input. On IC1.4 pin 14 connect a multimetero or oscilloscope and adjust SR3 untill the overdue signal amplitude reaches 2Vrms.