So I just recently got a Sony WM-EX631 Cassette Walkman from eBay. Its been pretty good the first month, had to replace the cassette door on the transparent case but other than that fine. Now, it seems there is an issue with the autostop/autoreverse function. The cassette was intermittently reversing to the opposite side at random, like in the middle of a song. Once I changed the mode to not reverse, now it just stops as soon as I hit play even mid tape. I’m wondering if the mechanism for detecting auto reversing needs attention. From what I’ve gathered they use some sort of transducers on a reflective gear to accomplish this. Is that information correct? If anyone knows anything I’d appreciate it.
The mechanism for detecting autoreverse needs attention.
Usually there’s a tension spindle that detects if the tape has ended, becauaw the pulling lug pulls and theres no more tape to feed.
Maybe the spring lost tension?
You need more info, probably an expert, but you can retension it by removing it and twisting it while heating in a fire (doesn’t work great but might be enough).
I bet this is it
I’ll check that out. The unit is in very good condition otherwise and I have the service manual. I probably will have to attempt to locate an expert. I’ve taken it apart since I got home and couldn’t identify the problem.
Sorry, also one of the capstans or rollers could be sticking, increasing the resistance which also signals that the tape has reached its end.
Interesting way to confirm: Does it autoreverse both ways equally? If so it is more likely to be the spring, if not then one of the capstans or rollers or the reversed lug is sticky.
You know what? Before I turned off autoreverse it was reversing at random and it would do so for a good couple of seconds before righting itself. Everything sounded fine, no assymetric speeds or anything. Maybe I should turn it back on and see what it does. Its set to no autoreverse right now. But I dont have the dongle so switching modes can be a guessing game. The WM-EX631 seems to have one capstan so its entirely possible the seller gave it to me and I wore it out already by being excited. At least, the service manual only points to the one. The pinch rollers are clear and clean too.
If the speeds are right, that’s almost a smoking gun for a weak autoreverse spring.
You might be able to jury-rig it temporarily, I don’t know this unit’s design, but either remove the spring and replace it with string or wire so the autoreverse sensor can’t trigger, or fix the spring itself.
Pull it and see what kind of tension it has.
Heat treating is the proper method to fix it, here’s the directions from chatgpt, it’s not wrong, usually I’ve just seen it kept relaxed and heated with a lighter for 10 seconds, then left to cool.
Thank you, I’ll attempt this the next chance I get. Hopefully I can source a new spring from fixyouraudio or something but in the meantime I’ll employ your method. I really appreciate the advice and just talking about Walkmans. When I get to it I’ll be sure to post an update here.
Np, good luck.
I miss my old Walkman from when I was young (actually think the one I used most was a Toshiba). Favorite was a Panasonic fm radio though, still love that thing, might have it in storage actually.
They were awesome for the time, best of luck with yours, ask if you have other questions!
Little update, the seller is just sending me a new unit. I will still attempt the heat treating though. The unit I currently have is really cool and it would be a shame to leave it in this state.
So I remembered how the autoreverse worked on my toshiba, there was a roller on a rocker arm with a spring, when that roller displaced from tension the rocket arm triggered the action.
I’m pretty much positive it’s the spring, but you might be able to test this by finding the rocker arm and adding tension with a paper clip to see if the problem stops.
Oh, the sensor itself could be glitching, but I kind of doubt that, the springs almost always go first.