I found this electronic organ in magazine published in 1976 from my vast collection of foreign magazines electronics. The circuit is still current because it uses the 555 and the transistors admit common equivalent. We can use the BD136 for BCY71 and the BC548 to BC108. This circuit has a vibrato oscillator given by TR2 and an amplifier stage feeding a small speaker. The keypad consists of metal taps or printed circuit board where we played with a probe. The tuning of each note is made to the corresponding trimpot and depth of the vibrato effect adjusted by VR26. In the original magazine article are suggested 25 notes covering 2/8 including overtones. Power should be done with batteries or source because the high consumption quickly spend one 9 V battery.
