I plugged this unit in and I could get it to run forward, fast forward and in rewind. I played a tape and I could hear the sound and music. I do not have a proper microphone but it ran on 3 3/4 ... 7 1/2... and 1 7/8. Need cleaning ... some scratches. The battery tester seems to work and all the switches and buttons seem to work however it may need some TLC so I am selling it as is.