Standard switching diode, DO-35 | | C4, C5 | 3 | 22k | Resistor | | C1 | 1 | B10k | \*\*Potentiometer, 16 mm vertical board mount. \*\* Use only four (4) potentiometers, either 9 mm vertical board mount. \*\* Use only four (4) potentiometers, either 9 mm vertical.