1969 National Solid State 4 Track System Portable Tape Recorder RQ-194S Analog Audio, Gyártók, Magnó, Orsós-szalagos National RQ-194S Operating Instructions https://audiomuzeum.hu/wp-content/uploads/1960/1969%20National%20Solid%20State%204%20Track%20System%20RQ-194S/National-RQ-194S-Reel-to-Reel-Tape-Recorder.mp4