FYI, the input knob would occasionally bind or there would be increased resistance. It still turned, but with a suddenly heavier feel.
Just back from the service center in California where they fixed a "mechanical alignment" issue under warranty.
This is a unit Tascam gave me to replace one on which the XLR clip fell out and then a tech in Massachusetts damaged wiring trying to fix it.
Love the way it records but in six years of heavy use I never had a problem with a Marantz 660.