2025-12-07 - Repairing a Sony Walkman WM-FX453
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Many years ago, I was given a Sony Walkman WM-FX453[0]. At first,
it briefly worked, but then the belt started slipping, so I tried to
replace it, but couldn't find a proper replacement at the time. The
replacement belt I found was much too thick, and it wouldn't work even
after I foolishly decided to break off a plastic piece so it would
sort of fit. When that didn't work, I put it back on the shelf for
years and only looked at it again about a year ago when I performed
this repair.

The back can be removed fairly easily[1]. I don't remember if there
were any screws or if it was just clipped, but it definitely wasn't
difficult to get it open. As far as I can remember, the circuit
board inside is only held on by one screw[2], so it's also easy to
remove[3]. Of course, the ribbon cables have to be disconnected
first. There are some cables going to the circuit board that are
soldered (as can be seen on the left in [3]). For regular work on the
mechanism and simple repairs on the circuit board, these can remain
in place since the entire board can still be flipped to the side, but
I decided to desolder them later to make replacing the capacitors on
the board more convenient.

[4] shows the piece of plastic that I broke off years ago when trying
to replace the belt. I found a proper belt this time, so I could glue
that piece back into place[5]. That plastic piece has to go through
a small hole in the circuit board, so I put the board on top while
the glue was hardening in order to avoid a small mismatch between
the position of the hole and the plastic piece.

The other issue with the Walkman was that several capacitors had
leaked[6], so I decided to remove all capacitors[7] and replace
them. The supercapacitor (the rectangular one on the right in [6],
or at least I think that was a supercapacitor) hadn't leaked, but
I also removed it temporarily in order to clean the corrosion more
easily. In order to remove all the corrosion, I first scraped away
all the solder mask in the places where it was corroded[8] (note that
I removed the plastic locking part of the ribbon cable connector
in order to access the solder mask underneath more easily). I
think I also polished the traces a bit with a fiberglass pencil,
although I don't really like that because small glass pieces end up
everywhere. As far as I could tell, the vias were still fine, but I
decided to solder some wires anyways in case the connections weren't
very good anymore[9-10]. There was also a partially ripped pad on
one capacitor, so I had to expose part of the trace leading to it
in order to ensure that there was a connection[11-12]. In the end,
I covered everything using UV solder mask[13-14].

My first recapping looked as shown in [15]. I had to be a bit
creative in some parts because I didn't have capacitors in the
correct physical sizes for all replacements. In one case, I had to
bend a capacitor to the side a bit so it wouldn't be too close to a
gear[16]. For reference, [17] shows the values (uF/V) and dimensions
(height/diameter/lead spacing) of the original capacitors that were in
each spot. Of course, the dimensions don't have to be as exact as
shown there, I just wrote down what my calipers told me. In some
places, there is more space, so larger capacitors don't pose a
problem, but that has to be checked for each one individually. I ended
up buying some smaller capacitors for the problematic ones, leading
to the final appearance shown in [18].

After all of that, the Walkman worked properly again, so the repair
was a success.


[0] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/walkman.jpg
[1] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/back_open.jpg
[2] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/board_screw.jpg
[3] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/mechanism.jpg
[4] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/broken_plastic.jpg
[5] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/new_belt.jpg
[6] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/capacitor_leakage.jpg
[7] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/capacitors_removed.jpg
[8] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/traces_exposed.jpg
[9] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/vias1.jpg
[10] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/vias2.jpg
[11] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/ripped_pad1.jpg
[12] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/ripped_pad2.jpg
[13] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/solder_mask1.jpg
[14] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/solder_mask2.jpg
[15] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/capacitors_replaced.jpg
[16] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/capacitor_gear.jpg
[17] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/capacitors_replaced_labeled.jpg
[18] gopher://lumidify.org/I/phlog/2025-12-07-sony-walkman-wm-fx453/capacitors_replaced_final.jpg