[Uncle Bulgaria]

Thanks, David. While I don't intend to regularly use it on batteries, it's pretty fun to carry it around in its case and have an impromptu dance or field recording. A little more convenient than a gramophone! Trying to set it up according to the manual is also an exercise I feel would be helpful for me to do.

I've revised my thoughts - perhaps it's to do with the tape-run Hall effect sensor (manual point 3.3) rather than the tape hubs. With the input at 6.6V (measured at Contact I in the battery compartment) it will play the beginning of a tape, but towards the end when 'play' is engaged it automatically stops after about a second. The trace of MP1 is not rectangular as the manual says it must be. On DC-coupled it's a very rounded waveform as shown in the picture, while on AC-coupled it's even less square and more like a rounded sawtooth.

Pk-pk it is approximately 5V, but no amount of fiddling with the sensor spacing affects the regularity of the pulse shape. Perhaps a component failure? Have you checked yours is a regular square-edged wave as the manual shows?