I have a little-used Sony Walkman Professional WM D6C
I inadvertently reversed the polarity on the power supply mini-plug (not the Sony original - the PSU that I used has a variety of mini-plugs which can be configured negative or positive on the central pin).
The mechanism is now running far too fast - playback, rewind and fast-forward.
It is too fast even when using batteries.
Can anyone help please
Regards
D L