Hey All! Newbie here! Just started getting into collecting walkmans and decided that my first project would be a Sony WM EX 633. Got one from Ebay whose motor was still working and gave it a decent-ish cleaning, swapped out the melted belt, and put it back together. Generally, it's been working fine, I'm sure I could do a bit of troubleshooting to fix some of the wow and flutter but for my purposes and skill level right now it's been great! Until recently. I've started running into this issue where hitting play will begin to play the cassette, then stop after a few seconds. I've been toying around with it, trying to figure out what's up and have been stumped. Further frustrating/confusing me is that occasionally it will seemingly fix itself and play tapes just fine (I think this rules out a faulty rotation detector). The only issue which I am aware of is that one of the capstone/bushing pieces for the flywheels is missing after I took it apart to clean it (ref 111 no 3-366-017-11 on p.23 of the service manual). I haven't taken the audio board off yet, I am trying to avoid doing so because that would involve learning how to solder, but I may just have to bite that bullet and learn some. I've done some tests trying to figure out if something is obviously wrong, I took off both the cover and front face and played a tape and tried watching the mechanism as best I could to diagnose it. The pinchroller/head seems to be contacting the tape properly (and for the few seconds it plays, I can hear okay audio), and then it stops. I think there may be some sort of auto-stop or safety mechanism which I am unfamiliar with that's being triggered. My initial theory was the lack of a capstone on the wheel (r, 118 p.23) was allowing it to drift too much and it stopped because of it. However, when testing, I shifted around the wheel and it didn't seem to fix or cause the issue. I'm a bit stumped/over my head at this point, and would like some advice if possible. There seems to be something happening when it's being played that causes the issues---the FF and Rewind work fine when pressed initially, when hitting play it will sometimes result in a clicking noise and cause the motor to go back and forth. It will also sometimes lock the cassette lid switch which resets the head mechanism. If I hit play then FF or Rew, it will make a similar clicking noise. I've attached a few images, I'll also upload a video of it running as I think that will be more helpful than anything I can describe/show in one image. 1. Any ideas on what this issue might be? 2. Any suggestions for how to troubleshoot further/what to look for? Thanks for reading all this!!!
In regard to part 111, that's not necessary for operation it's there only for aesthetics and for the cassette shell to slide easily and not catch. What is needed is the capstan retaining washer 112, which I don't see (usually it's green in color). Next thing I would do is clean the mode swtich with contact cleaner. The camgear may also need cleaning and re-greasing. The gear noise you hear is motor rotating in opposite direction of camgear engagement, after the plunger has already been released.
