Hello again. This time I'm operating on a SONY WM 7. After I put a new belt on the WM 7 and did a function test, I unfortunately have to find out that it only plays well in one direction. Unfortunately, he stutters in the other direction. It seems that a couple of gears don't want to grip. Does anyone know the problem and can give me a little tip to solve the problem? I also made two videos of it.
Today I tried to take the Walkman apart. I suspected it might have something to do with the wheels on the control board. After looking at it, however, I don't think it has anything to do with it. The wheels only set the course to play in one direction or the other. It appears that the light wheel that is connected to the flywheel does not properly engage the dark gray wheel on the control board. I made two videos with close-ups of the inside. One of them is in slow motion.
Unfortunately I can't get any further. I also tried to exchange the bright wheels with each other. Unfortunately, that didn't work. Does somebody has any idea?
Hello Gab I too have this problem on my favourite machine. Before I start work on it, I was wondering if you got any further since your last post?
Unfortunately, I haven't had enough time to continue working on the Walkman in the last few months. But I got some interesting pointers on YouTube. You can read that through. If that helps you, please let me know, then I will hopefully be able to try it out soon. A YouTube User wrote "I bought a SONY WM-7 which after cleaning and replacing the belt has the exact same problem you are showing here. I examined it and draw the conclusion: the reverse table reel (the lower portion which engages in play) is badly deformed. It's oval. That's why it's not engaging the teeth in some portions of the wheel. It can be seen clearly if you remove the metal protection on the cassete side and run it without a cassette in place. You may try to warm it and twist it round again while it's hot, but that's not a guarantee that it will actually work. Most likely all WM-7s have this problem, it seems like a design issue. And SONY had a lot of problem with plastic gears in all types of cassette players and recorders."
It looks like from the videos the sliding gear engagement device is jammed and not moving properly in one direction. The gear doesn't look out or round or trueness from the video. It might have shrunk in circumference though also. See if you can analyze the mechanical engagement mechanism that slides back and forth from left to right near the top of the walkman in the video. Not the multiple gear device you have dismantled in the photos. The servo motor or gear might be damaged or jammed some how.
Table Reel 3 by Valentin posted Dec 20, 2020 at 5:37 AM Hi Gab, I since deleted the comment and found the real cause of the problem. The table reel gear, although it's not perfectly round as I have stated in the comment, it's not the cause of the problem. Actualy the repair is much simpler than I have thought: all you need to do is remove both table reels (I say both because I did this process to the forward reel as well, as it was a little bit loose also, although not as bad as the reverse one). Next you need to remove the top part (the reel itself). Below that is a white plastic part that needs to be pushed down firmly against another white plastic part. They become loose over time so the black gear will wobble. The 2 plastic parts that need to be pushed toghether I marked with an arrow. It is not necessary to diassemble the table reel as I did, you can do the producedure by just removing the top part that spins the cassette. I would NOT recommend to glue them, as they will stay in place for a long time. If you want, you can completely disassemble the reel and clean it, although it is not necessary. I also put some oil where the white plastic part slides against the black gear (a personal preference, it's not necessary to do so). What is necessary though is clean the metal shafts on which the table reels are mounted and lubricate them with oil before reassembling them. Also be careful with the washers, as they will fly out if you don't keep your finger against them (there are springs below the table reels). Hope this helps !
I hope you're right Valentin. Although dismantling any "quality" Walkman is never easy. Well, dismantling is easy, it's the re-assembly that requires concentration.
It’s not advisable to put any oil there. That white nylon between the gears acts as controlled slippage, that section is a clutch. If you want to wreck that Walkman by all means put oil there.
I think I didn't make myself clear. Not on the nylon washer, but here where there is friction between the 2 plastic parts. And I put a tiny amount so it does not get down on the clutch mechasim below. Table Reel 2 by Valentin posted Dec 20, 2020 at 5:31 AM Indeed the nylon wahsers should be clean of any substance as they are part of the clutch mechanism, which is magnetic in this case. I did this repair about 2 months ago and it works perfectly to this day. Gab already diassembled his, so I am sure he can do this no problem.
Hey Valentin, thank you very much for your detailed explanation. It sounds good and as soon as I find the time, I'll try it out and let you know if it worked for me. I am happy that you and the others help me with my problem. Greetings and have a nice 4th Advent to you. Gábor
Hi Valentin, I'm experiencing the same issue on my WM-7. However, regardless of how much force I use, I cannot get rid of the play in the black gear. How do you go about disassembling the table reel completely? Are there replacements somewhere?
Hi dmandras, I think a lot of people experience this issue on their WM-7; I personally consider it a known problem now and think that all WM-7s will have it sooner or later. The 2 white plastic parts get loose over time, creating play in the gear, hence the sttutering. It is to be mentioned that the gray gear also gets loose, but given it has less play, it doesn't stutter. That one also needs to be fixed, although no symptoms may show (apart from high wow&flutter). You do not need to disassemble the table reel completely. You just need to remove the top part that turns the tape (marked in red). After that you can press on the white plastic part. Replacements are not available for sure, but I'm also pretty sure you do not need a replacement. I may be doing a thread with all the common problems on this unit and how to solve them, as it does have some of them (and do a very detailed explanation of this table reel issue). Most people buy a WM-7 thinking it will be just a belt (I think the sellers asking for crazy prices think the same). It's almost never just a belt, of course assuming you want the walkman to be back to original specifications, not just to work. P.S.: You need to remove the servo plate (first part in my picture) in order to service the table reel.
Now I understand what you meant by regardless how much force you use they still slip. Maybe the unit was used with this problem for a while and created wear in the pastic parts. If the top was not broken, I would have suggested glueing them toghether (after installing in the table reel). In my unit and several others I have repaired the 2 parts where very firm to one another without requiring much force to push them; just a little bit and snapped into place, eliminating the play in the reel. Please post the result if you manage to make a 3D printed one, other members might need that part also.
At long last, I finally got mine working. I gave up on 3D printing, but have spare parts if I ever get the opportunity. I got a spare WM-7 off eBay for what I considered a reasonable price, pushed the table reels back together the correct way, swapped them in and it works perfectly now. There's a bit of an audio balancing issue, but that should be simple to fix, as it only happens at certain volumes.
I had the impression from the beginning that 3D printing is not an option: parts are not strong enough, nor precise enough in terms of dimensions. Glad you finally got it working with spare parts from another device. As for audio balancing issue, the potentiometer absolutely needs to be cleaned on these. And then the Dolby levels may need ajustment (these can create imbalance, but it will happen at any volume) and the modules depotted.
