WM-A602 (WM-B602) issue after new belt

Discussion in 'Tech talk' started by bplanes, Jun 9, 2024.

  1. bplanes

    bplanes New Member

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    hello Everyone,
    so i have a problem: after changing the belt of my A602 (i really like its design) , it seems something went wrong with the player mécanism.

    >>§when play button was pressed, tape seemed to turn not in the same dir than the capstan... then. i moved one gear to try something and now it plays and stop after a second (like if reaching the end of tape) ...
    concerning FF and REW : stops after 1 sec...

    my intuition : gear or/and switches are not synchronized anymore.
    I probably moved something during cleaning and before installing the new belt... what.do you think?

    i checked the 3 switches via the 3 holes on the PCB board and they are well located... (see picture)

    voilà... i prefer to stop now and ask on the stereo2go Forum some help before doing mystake.

    so thank you by advance
    b
     

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  2. Valentin

    Valentin Well-Known Member

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  3. bplanes

    bplanes New Member

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    Last edited: Jun 10, 2024
  4. Valentin

    Valentin Well-Known Member

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    A broken clutch gear can cause a jam in the mechanism. Your camgear seems to be half-way between FWD and REV, see picture attached.

    From my point of view, given the clutch is known to fail that should be replaced first.
    When I repair these mechanisms, I do the following before even powering up for the first time:
    - replace the clutch gear;
    - glue the tabel reel gears back to their shafts; you can see the white gear near the motor has a crack in yours. Chances are the other one has the same issue.
    - lubricate the capstan bearings and motor; this really depends on repair skills, if you're not confident skip this step;
    - install a new belt;
    - replace the capacitors if leaky;

    This way, when I power the unit on, I know all the common issues have been solved already. So if there are any additonal problems, I can already exclude some of the causes.

    As for the link, I recommend replacing the clutch with a new one, no point in repairing it. There are links in my common problems thread.
     

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  5. bplanes

    bplanes New Member

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    hello. Valentin
    hope you're summer was great, I'm back from mine, sorry for this delay and thank-you very much for your help.

    back to my studio i finally unmount the mecanism

    you were super right:
    both white gear and black gear/clutch were broken...


    i m lubrificating and checking... nothing else.
    I'll now try to order those parts, I'll browse now forum and your "common problem" thread to find new gear and clutch and replace them... if you know any link.

    thank you again ☀️
     

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  6. Valentin

    Valentin Well-Known Member

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    If you want a full kit containing all 3 gears, this has all (but it is more expensive): https://www.ebay.com/itm/314978961246
    There's also a kit containing 1 x clutch gear and 1 x reel gear, but you will need 2 such kits to get the 2 reel gears: https://www.ebay.com/itm/335392051559

    To be noted both reel gears tend to break, not just the visible one.
    However, these can be repaired (unless they're cracked all the way, which is not the case here) by adding a small drop of glue on top.
    In case you want to replace just the clutch gear and repair the reel gears, go for the FixYourAudio clutch gear: https://fixyouraudio.com/product/sony-wm-a602-clutch-gear/
     
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  7. bplanes

    bplanes New Member

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    hello Valentin,
    thank you so much for all details, following your instructions I just ordered 2 kits (clutch and reel gear) for my 2 wm A602
    as explained i plan to test glue on the reel which is still in one piece > cyanolit can make the job ? in the worst case I'll order another kit but I like as far as i can to keep as original pieces as possible :)

    waiting for delivery now, from now I plan to lubricate the motor trying to remove smoothly the coil... but it seemed glued or well fixed...

    thank you again for all your advices and links!
     

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  8. Valentin

    Valentin Well-Known Member

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    Yes, cyanoacrylate based glue (known generically as Super Glue) is good for repairing the reel gears.
    You just need to add a small drop on top where the shaft is.

    In regard to the motor, heating the metal case of it (on the outside) with a soldering iron will help soften the adhesive.
     
  9. bplanes

    bplanes New Member

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    okay thank you Valentin, I'll try my best :)
     
  10. bplanes

    bplanes New Member

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    hello, I'm finally back.

    as advised by @Valentin
    I cleaned and lubricate the engine
    I received the gear kit and just replaced today them on two A602 units having the same issue (2 gears replaced on both unit).

    The process solved the mecanism problem (thx Valentin)


    now I have 2 new problems:

    - as you can see on the picture one of the grey disc holding a gear is broken - >is there a way to replace or repare it? (because of the quality of the material, it seems tricky to glue it)

    - on both unit when I play a tape I don't have sound (!) ... just breath noise, like if the tape as no sound. when I change the volume the breath noise change as espected proportionnaly ...

    could it be a switch somewhere on the board... a leak capacitor?

    thank you ☀️
     

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  11. Valentin

    Valentin Well-Known Member

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    Not sure if it's worth trying to repair that disc... Given there's quite a bit of force when clutch is slipping, chances are it will fail again.
    Would look for a donor unit, as it's good to have one for parts anyway. Look at post #17 here (any from the list will work as donor): https://stereo2go.com/forums/threads/list-of-walkman-portable-recorders-common-problems.7535/

    In regard to the no sound situation, it's most likely caused by failed capacitors. Given you do have noise, the amps are not muted.
    Look for leakeage around the electrolytic caps.
     

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