here is the run down on why i do not mess with them if they work i leave them alone .. walkman are designed to be small,,lightweight even with batteries but opening one up is a diffrerent story mostly the wires are super thin i mean thin if u do not watch out u can pull it off very easily even worse if u did not look at all the wires were they go and it come off i do not want to think about it
if its a wire attached to the condenser mic and its hidden u have desmantle the whole thing just to solder the wire while trying not to pull the rest of the wires apart
then trying to seperate the main board holding it while trying to remove the super small screws and if they dont want to come off then there is this big fight
and then some more wires being snapped off
,,then there is the belt issue which has to be thin if not it will rub against the metal plate or worse yet not move at all so u need the correct belts,,other than that if u have sound issues or somthing is not right ,,some component are very small boards are small traces are very small ,, if u have the time and mostly patience to deal with the above then go right ahead ,,it really takes a steady hand having a table where u can set it down and desmantle the sucker all btw remember the small plastic parts they can snap easily ...that is why i do not work on them,i have done a couple of them but each one will be either much harder or not that hard..