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.