My Sony TC-D5M

[vin45]

I have a TC-D5M that functions well but for one fault: There is a rapid low frequency noise (like, du-du-du-du-du-du, sort of...) on the left channel only on playback. There is a similar, quiet mechanical sound from the deck when recording from line in, but the noise is not on the recording (recordings are excellent!). Any thoughts about what might be the trouble?
Thanks!

 

[tapetech]

Try cleaning the rec/play mode switch with D5.