I thought the 2000K was a 4 track (at least 2 tracks either direction) so it should play the Sony tapes recorded in stereo on 2 tracks. I understand this model was a development of the Stereomaster 610K 

Ah just read the spec properly - maybe I do have the 2 track version after all... not sure how I can tell though

You can look at the tapeheads. If there is a gap between the two track elements of apprx the
same size as the elements themselves, you have a 4-track.
If the elements are close together, covering almost the entire tape width, it's a 2-track.

A tape recorded on a mono machine will typically have one track playing fine with the other track
playing something else in reverse.
On a stereo machine, you must then play only one channel at a time, typically the left one.

Having said that, there were uncommon recording formats around that will only play correct on the same type of
machine that recorded the tape.

Martin

Thanks for this scan Martin. I have a DeLuxe which I found in the electronics thrash dumpster where I live. After replacing the pinch roller, it plays fine but I couldn't check all functions as I didn't know what all buttons did.