Hi Guys, I recently picked up a defective WM-7. After cleaning out the remains of the old belt and putting in a new one and replacing the pinch rollers, the take up reels of the machine were stuttering, after cleaning the clutches with isopropyl alcohol the reels now run fine. The problem that the Walkman now has is, that one side is playing way to fast while the other side has the correct speed. It seems like the pressure is too low on the fast-playing side, or is the issue caused by something else? Can the pinch roller pressure be adjusted? Does anyone have had the same issue with their WM-7.
the pinch rollers on the wm-7 are engaged by the internal switching lever, which is engaged by the 2 worm gears whenever you press one of the directional buttons (you can hear them whirring away when you switch direction) might be its not centered in standby, youll have to disassemble it and manually set it to the standby position (ie center it), if that is the cause. youll be able to tell if one pinch roller is slightly engaged when its stopped. though im unsure of how that problem would even arise so its pretty unlikely it could also be the worm gear responsible for the other side needs new lubrication as it cant fully engage the lever properly. which is probably the simplest issue to correct here (provided its a pinch roller engagement problem) there are also 2 gears inside for the corresponding direction, problem could lie with lubrication or dirt gumming up the gear responsible for whichever side is running slow (if it cant spin the take up reel properly it will slow down, since its driven by a gear underneath one of the flywheels) quite a lot of moving parts that could be responsible, plus common issues like dried up pinch rollers, wont be going absolutely everything but hopefully this helps
@Benjamin0817 The issue can be caused by too little pressure applied to the pinch roller, to the point where the tape simply slips through and all the pulling force is given by the takeup reel instead of capstan. Unless you bent some parts during the repair, there's really nothing to adjust. The pinch roller pressure is given by the force of the spring. If the lever was a problem, the mechanism would reverse as the mode switch (which is embedded into the camgear) would never go into the fully loaded position. You would also hear the motor is struggling to engage but without success. Note that hexagons in the reels that hold the clutch get rounded at times, requiring them to be glued; When did this problem appear exactly ? After you cleaned the reel clutches or before ?
Thanks to both of you for the detailed answers. Well I bought the WM 7 used after repacing the old belt and the pinch rollers the machine worked again only both sides ran too fast. After cleaning the clutches one side is working properly only the other side is running too fast. It looks like, as both of you mentioned that the pinch roller is not putting enough pressure down so that the tape slips. Could it be that on the worm gear is some what deformed and is rotating on the motor shaft when more torque is applied ? Edit: After swapping the black springs around that are visible on the front side, the walkman shows another behviour. The working side is still working, while the other side now runs too fast and than slows down to a stop in around 2 -3 sec and than the machine switches sides.
with that information id assume its an engagement problem, probably the worm gear if i had to guess (or one of the gears it engages with). id try taking it apart and cleaning/lubricating those parts (if you dont know what to use or dont have any on hand id highly recommend molykote em-30l, safe for metal and plastic parts) if you could upload a video showing it run though that would help a bit with identifying any problematic oddities its displaying when running. id be lying if i said i wasnt doing a moderate amount of guesswork currently lol
Well here is the video, sorry for the crappy quality but I do think that the problem is clearly visable. https://youtube.com/shorts/CfPV6oTfqQM?feature=share The cleaning and greasing I will do at the weekend. If I done that, I will report back. Thanks again.
eh yeah not as insightful as i thought it might be, all i really noticed was the motors sound a little higher pitched than mine do. which tbh is probably more of a sign i need to go through and lubricate mine than anything else best of luck with it, i probably wont be much further help with diagnosing it
There is only one motor that drives both FWD and REV. The second motor is for FF and REW. Watched the video, judging by the sound it seems to me that the camgear is fully engaged. As stated before, that camgear has a mode switch in it, so if the mechanism would not engage completely the microcontroller would sense that and drive it back into the neutral (STOP) position. Pinch roller does seem to engage, but it's unclear if the spring gets compressed by the lever. This is what needs to be checked. However given what you stated that both FWD and REV ran fast initially and REV started working fine after cleaning the clutch, this would suggest the problem may be in that area. On some of them the motors do sound higher pitched than others. This is actually a good sign, to me it indicates things are moving freely. Which black springs have you swapped ?
These two springs I swapped around. I cleaned out all the old grease and lubed all moving parts with a very light coat of fresh grease. The fresh grease did not change anything. What I noticed on the too fast running side is, that the tape moves to the top of the pinch roller. Where it than gets curled up and than gets stuck and the walkman switches sides.
The 2 springs are used to move the 2 metal arms into position. Those parts hold an intermediate gear which transfers the torque from the capstan to the reel assembly. It's common for those 2 metal parts to get stuck, causing the reel to not turn as I've mentioned before. However you don't seem to have this problem, at least it's not hapenning in the video. As for the tape moving up at the pinch roller, that would indicate there's an aligment problem roller not being parallel to the capstan. Do some checks without a cassette inserted: move the door latch manually into closed position and put unit into FWD play. Then try to pull the pinch roller away from the capstan. See how much force does it take to do so. Also put your finger on the roller and see if it moves in tandem with the capstan or it can be easily stopped just by lightly touching it.
I tried stalling the pinch rollers by hand and I can't really feel a diffrence between the sides. The same goes for lifting the pinch roller arms, I couldn't feel a force diffrence. I bent the left pin for the pinch roller arm very carefully to the latch for door and now the tape doesn't up on the pinch roller. Now the left take up reel stutters but it appears to run at the right speed.
sound advice, always try diagnosing before jumping into adjusting/doing unnecessary stuff id do what valentin said before fiddling with anything else, wouldnt wanna get it too outtah wack trying to fix the wrong problem and winding up with a mess of things to fix god knows ive made that mistake too many times lol
Not sure if some of this has already been mentioned... but these tips may help: 1. The old belt can get sprayed around in the mechanism if the unit is powered on without the old belt being cleaned off first. If you think you removed all of the old belt, think again, and re-examine everything... I cannot tell you how many times I've found tiny bits of the old belt in a hidden spot, like under an armature or gear. Even a tiny drop of rubber goo can wreak havoc on a small mechanism. Given the history of your comments in this thread, looks like the problem is sporadic (symptoms change frequently), and that can be another sign that it's left over goo or old grease. 2. Re-apply lubricant to the mechanism, and also remove the old. Grease when new is silky and the least bit tacky, but when it gets old, it becomes very sticky, and therefore causes parts to stick. Remember that the tolerances in these units are tiny, so the room for error is basically non-existent, which therefore means the tiniest of sticky grease can make a big difference. You need to be disassembling the mechanism to re-grease it properly... as this is how it was done by Sony originally... add lubricant to part, insert it into the mechanism. 3. This summarizes the two tips above. It's not enough just to add new parts into the unit, you have to maintain it as well. Just as you would change the oil/fluids/plugs in an engine at the same time you replace other broken parts (water pump, manifolds, gaskets), you need to service these Walkmans in order for them to work after new parts are added. You do this by: Remove battery corrosion/loose debris from the inside case and mechanism Clean all parts with isopropyl by removing them from the mechanism Reassemble mechanism adding your new parts & adding grease as you go along 4. Do not do all of the service at once and then test. Again, with an engine you do one job at a time, then test the engine to see how it responds differently after the work has been completed. You want to be accountable for the work you do, and checking behind yourself is how you validate if what you have just done helped... or hurt. Similarly, when recapping, don't replace them all and then test... do them in groups and test frequently. These tips helped me tremendously... too bad I didn't have a list such as this. Good luck!
The stuttering can be caused by 2 things: - the intermediate gear not fully engaging due to that arm having old grease on it; - the hexagon in the table reel clutch may have rounded and need glueing; From the video it seems that you may have both problems. For first one, just check without a cassette inserted and plate removed. As for second issue you can stop the table reel with you hand, you'll feel the stutter in the reel itself if the hexagon is rounded.
Thank you all for your help. It was the intermediate gear that wasn't completely engaging. Cleaned the sliding plate again and put some new grease in there. The WM7 is now running again and works perfectly. Thanks to all of you.
