i have no way to test this unit. sold as is/parts even though it does appear in good shape.
it does power up just fine and all the knobs and switches appear to move freely as they are supposed to.
Red Record lights fire up when record feature is engaged
made from 1978 to 1982
Heads look ok, i know the Ferrite heads wear slow so i would expect them to be in fine condition.
Message me with any questions, thanks for looking
More info;
The TC-399 has large-sized VU meters which indicate the average level of complex musical waveforms.
Other features include high performance Ferrite and Ferrite heads, tape bias and equalization switches to obtain the maximum characteristics according to the type of tapes, and a tape tension regulator to reduce wow and flutter.
Specifications
Track system: 4-track, 2-channel, stereo/monaural system