Here's a beginner's (very) basic guide to taking apart a wm40 to pop in a belt

Keep the unit in its extended state preferably with a cassette inside (to prevent it from going to the collapsed state which can be a bit cumbersome later) an try remembering to prevent it from collapsing if there is no cassette inside.

Go for it in two steps first. start with the bottom end and its three screws first and then the back of the player and its 4 screws. The bottom has a portion of the cassette door engaging mechanism that runs through it...so you have to jiggle it off...take care to remember how it seats so that you can reseat it the same way.

With these exquisite units if you drop a screw you are screwed so try being a little careful with these tiny fellows. I'd advise a sheet of paper folded over a fridge magnet onto which you can stick the screws in order by category so that you don't lose or interchange screws

No harm in placing a 'number' next to the legend in case a screw tries crawling into the neighboring category so 4 screws for the back, 3 for the bottom end....

A non slippery pale colored work surface is good...I use an ivory colored silicone mat (that we dentists use to place our working instruments on )

Before you can get the back off you'll need to do a bit more of unscrewing and digging in ... a) removal of the decorative chrome ornamental panel ( 2 screws_ to uncover one of the battery door screws b) removal of the batery door (one hidden screw below the decorative panel and one on the outer edge of the walkman body)

After you've removed the ornamental panel and battery compartment door you can now remove the back shell from the mechanism by gently prying the side opposite the headphone jack first and then slowly going around easing it out at an angle...No big deal ..just that it is easier if you don't start from the headphone jack side.

Careful about the Dolby and Tape selector switch sliders. I like to place the switches in Dolby 'Off' and Tape 'Normal' positions all through disassembly and reassembly.

Now we are almost there...just have to unscrew the two screws holding the pcb in place. Someone had already been in this unit before...so there was only one screw .

The belt was one big mess of black gooey gunk everywhere. I sat with some isopropyl alcohol and a fine Bard parker scalpel blade to pry away most of the lousy residue. NOTE : If you get lazy a) the sticky stuff will stick to your fresh belt and mess it up b) residue deep in the grooves will allow only intemittent seating of the belt giving you 'shock and awe' category 'wow & flutter' your best singer on tape will be warbling like mad. So clean, clean, reclean and clean and then clean and when that has been done clean it up one last time I did it...thrice...no jokes...I got lazy & impatient to get to the finish and a) messed up a replacment belt b) had a nice session of warbled playback

TIP:there are these belt guides in two places...a) one over the motor as a motor housing plate and b) near the smallest pulley.

So you might feel it is easier working with the motor plate unsrewed and taken off and similarly you might want to stretch the belt and push it in by the side of the tiny pulley to get in it...much like flossing

The belt I used was one of the rarer 'large diameter' belts ...approx 0.7mm square cut 85mm dia. It gets a bit confusing with any belt after 70mm dia..small variations seem fine...you can stretch a slightly smaller size to make it fit as long as you get a good final result. The one lucky thing is that if the size and tension of rubber isn't right you'll know straight away...things won't sound proper. It sometimes feels nice to have an assortment handy just in case you want to try one largeb smaller or larger before you start closing up the patient

Naturally it goes without saying that you'll retrace your steps extra carefully and end up with a lovely deal of a Non Working unit converted to working with just a simple belt change...or if you botch up you are my next best friend providing the community with a unit for parts 'Careful'... it isn't rocket science ...just a little attention...that's all

terrific! that's exactly what a beginner like me was looking for. great job DocP

Can you do this for EVERY walkman ever made DocP.....I'm not asking too much am I

Stellar work...as usual Docp!!!!

Thanks for the kind words folks...one good turn deserves another here's the manual too

http://alturl.com/oiuno

Good tip, for the magnet as well....i do the same in labeling all the parts and some screws on a piece of paper...but i use a piece of clear tape over that part...

lol ever seen a unit with a 50mm belt inside ?

I won't mention names

wm 100 series

no it was inside the wm-40

Ouch - wonder how someone managed to stretch it out  unless they just popped in the belt 'loose' to indicate the wm40 came with 'a belt' ?

Any idea where i can get a belt to suit? Looked on ebay and none available.