Hi Valentin, I have thoroughly cleaned the pinch roller and capstan, they're pristine. They're parallel and when the roller touches the capstan it does so by the middle of its barrel shape. I have tested several different tapes and I really can't understand what's going on. Some are perfect, some show some slight imbalance, I guess it could be due to either original recording, or to the fact that the musical scene is not centered (e.g. instrument more present in the left or right channel on purpose). Eventually, I managed to narrow down the issue to only that of wow & flutter - at least I believe so. Indeed, when recording at the beginning of my brand new tapes (TDK Super CDing 90 Super Avilyn), i.e. take-up spool empty, I've managed to have a pretty good balance (see attached RMS analysis of the recording of a 315 Hz signal through Line In) - so I believe that my issue was indeed coming from the pinch roller and has been solved by its replacement. I am therefore left with the wow & flutter issue - which gets worse and worse as the tape advances, up to a point where the tape will simply stop while recording. I suspect the issue is with the frame that holds the pinch roller, or the spring that hooks it to the head carriage, which create too much pressure on the tape. I've identified that if I slightly press on the frame holding the pinch roller, that wow & flutter effect disappears - see video: https://www.swisstransfer.com/d/43d3dbe2-b6b2-4a84-b4bd-16ff33acda4e Does that make any sense? The big spring looks symetrical to me, could it be that when I put it back I switched it and that it created the issue?
That is something only you can tell, but if that imbalance is not present while playing the same tape on the WM-DD33, it's pretty obvious the problem is not in the recording. Pretty unlikely that there's an imablance in the recording done on purpose, but of course it's not an impossibility. The attached RMS measurements is near perfect if you ask me. What I would be concerned with is not so much the value itself, but if this values is consistent with all tapes and at every playback/recording. W&F - too much pressure or too little pressure on the capstan can create high w&f. If the pressure is too high, it will load down the motor too much, making the servo unable to maintain a constant speed. This has to be extreme though. If the pressure is too low, the tape will simply slip between the capstan and the roller, as the takeup reel will put more force on the tape than the capstan. Watching the video, it seems like you increase the pressure, so it's the second scenario (which is the most likely). As for the springs, the black one is symetrical doesn't matter which way you put it. However I believe something else might be going on: somehow the head bridge cannot fully move into position. So you need to check everything as you most likely put something wrong given the problem didn't exist before replacing the roller. Assume the roller itself is rotating without any resistance.
Hi Valentin, It's taken me a while as I was a bit lazy, but I've now checked the whole thing again - i.e. went through the whole capstan roller replacement procedure once more, removing and putting everything back together. I'm sure I've put everything back properly, springs and all, but the problem is still, stubbornly there. I initially thought that I potentially had a problem with the axis of the capstan roller which would have been in contact with the head carriage, therefore preventing free movement, but now I'm sure it's not the case. The W&F is still there but I have no idea where it's coming from. Actually I'm talking about W&F, but it's more like the closer I get to the end of the side, the worse the issue and the slower the tape is playing, until it (almost) stops (it did stop in one of my recording attempts). I believe it could be a tension issue, since the problem only shows when my recorded tape is nearing the end of the side - at the beginning of the side the issue is not present. In another thread I had a doubt whether I was missing a spring on the supply reel (the one on the left above), but we said that backtension would be ensured by the counter belt, so I'm not sure... Or, could it be that the reel should be a bit "higher", i.e. its shaft not too much pressed into the small reel gear, so as to create the needed tension in the spool? (not sure if I'm clear). I'm really out of ideas now, other than trying to adjust the capstan wheel top screw, in case it can solve the issue. Any other suggestions? I can put a recording in case it helps identifying the issue.
Backtension is something non-critical in compact cassette machines, since there is a pressure pad that creates tension in the tape and a good tape/head contact. This is different in helical scan devices, where for the tape to make contact with the head drum you need backtension in the tape otherwise it won't touch the drum. Compact cassette machines will actually work even without any backtension in the supply reel at all, even without the supply reel being there. There were very cheap walkmans back in the day that didn't have a supply reel at all, just a plastic shaft to keep the reel of the cassette somewhat centered during rotation. So unless you have a cracked small reel gear (this one: https://fixyouraudio.com/product/sony-wm-d3-small-reel-gear/) and the crack is creating intermittent drag, wouldn't even look there. To little backtension won't be a problem for wow&flutter, rather the opposite. So recommend to just check by rotating the supply reel by hand and see if it moves freely. There should be some resistnace, but not a lot. And the resistance should be cosntant on the entire 360 degree cycle, not having any points of higher resistance. About flywheel thrust play adjustment: there's a simple check you can do. Press on the motor so the spindle isn't touching the rubber disc anymore and move the flywheel up/down. Do you have any play ? There should be a little play, but not much. If you don't have any play and the flywheel is very hard to turn, that is a problem. Otherwise look elsewhere. This adjustment despite being important for wow&flutter, is not gonna make the difference between 0.6% WRMS and 0.08% WRMS. When you're at 0.6% the problem is much more serious than a simple adjustment. The 2 adjustments (motor position and flywheel thrust play) are more for fine tuning (the adjustment range is not huge) than to make a very audible wow&flutter non-audible. Ok, then comes the motor itself. I've seen situations where the motor is seized on DDs and this creates huge w&f. Do the same check as above with rotating the flywheel by hand, but this time without pressing on the motor. Does it turn freely in both directions ? If it has increased resistance in one direction you need to lubricate the top bearing of the motor. I would also clean the rubber ring with IPA just to be sure that's not a problem. Usually it's good practice to clean the contact surface before installing the flywheel. Then, does the pinch roller rotate freely inside its metal carriage ? This said, just trying random things in hopes something will be the fix is not a good approach. Unfortunately it's hard for me to diagnose your unit since I don't see it. So these are only suggestions, the problem may be something else entirely. Also, given the problem appeared right after you swapped the pinch roller, the most likely scenario is you disturbed something when replacing the roller. Then, of course, it is possible something else broken at that time but this is less likely. I would especially look at the roller itself and if it's able to freely rotate in its carriage.
Thanks, I will do the tests with the motor and flywheel. For the small rear gear, I replaced it already, together with the central gear and counter belt, it's brand new. I really can't see what I would have disturbed when replacing the pinch roller, I was really carefull. But the problem definitely appeared after I replaced it so it must be linked - the cassette I am playing and which now shows this issue was recorded before the pinch roller replacement, and when played on my other WM-DD 33 plays correctly. Could it be that the tension of the spring is not strong enough? It doesn't seem distended though. I also checked before remounting everything that the support for the pinch roller (marked with the arrow) was perfectly flat... To me everything looks normal in this area, and the pinch roller is moving freely... If I can't find anything with the other checks mentioned above, my last hope would be to ask: would you take my WM-D3 in for a diagnostic/repair? we can PM to align if you're ok and if I can afford.
Ok, so the part with small reel gear can be ruled out. About changing the pinch roller, of course as stated there is a possibility a second fault occured at the same time, but it's less likely. The tension of the spring, you haven't changed that and the tolerances on it are not that critical so changing the tension by 1% makes the difference between working and non-working. Spring looks good in the picture, there's no reason to suspect it from what I can see in the pictures. Only additional thing to check is if the head bridge is able to move fully into position, make sure it's not stuck as that will restrict the tension on the roller as well (as roller has very limited movement by itself). As for taking your unit for diagnostic/repair yes can do that. Feel free to PM me.
Great, thank you! I will contact you when I get fully desperate I've managed to get another WM-D3 unit for very cheap (I was super lucky) that I will repair later on. I can use it as comparison point for now, since I didn't touch it yet. It was sold as non-functioning and only for spare parts, but I believe comparison is still valid. What I see is that the distance between the pinch roller and the capstan is higher on my under repair unit, than on the comparison one... That's weird, because I've checked the original pinch roller diameter with the new one (I've bought 2 from FixYourAudio shop so still have a new, spare one) and they're the same at 8.7 mm (that said the precision of my caliper may not be enough to actually show the difference) - still I can see a difference, which is visible if you zoom in on the 2 images below. I've also filmed the movement of the head carriage, which seems normal to me: https://www.swisstransfer.com/d/c58ec4a3-75cf-401b-a79b-07cb41dc2dc2 I suspect the wider gap between the pinch roller and the capstan is my issue, but I really don't understand where it can be coming from, as the head carriage seems well assembled and the pinch roller diameter is apparently the same...
I can see the small difference you mention in regard to pinch roller position. Can be related to the position of the roller assy or the dimension of the roller itself. In regard to the measurement, a caliper is more than enough to measure the diameter. Differences of less than 0.05mm (which is a typical resolution for a caliper) are completely irrelevant in this case. Looked at the video, with carriage in opened position I can see it can extend beyond the normal loaded position, so apparently it seems to be working fine at least in opened position. However, there are still some things to be checked: note that the head bridge has a stop point on the plastic part (see picture attached). Does the head bridge extend up to that stop or not ? Also, when in PLAY, does the small black spring get more tensioned compared to stop ?
Hi Valentin! I've been scratching my head for the past few days, observing everything and trying to identify the root cause... I understand from our exchange that my W&F issue is coming from the too low pressure the new pinch roller is exercising on the capstan - right? Then, I believe it is due to the higher gap between the roller and the capstan than the one I can see on my spare unit - also given the fact that if I put some slight pressure on the roller assy it is correcting the issue. What I can't understand is where this wider gap is coming from. Roller diameter is the same, springs hook as they should, can't see any difference between the 2 units in that respect. The one thing I suspect somehow, is that the playback head is protuding a bit more on the spare unit, which in turn would make the pinch roller closer to the capstan due to the small black spring - see first set of pictures. Then, I tried to understand where it could be coming from, and noticed a very slight difference in the plate holding the screw in the second set of pictures, with the one on my unit slightly protuding backwards - see second set. Yes, I have uploaded a new video to show: https://www.swisstransfer.com/d/fcf57f50-009a-4246-b30d-305631d6f288 Yes, it does. Would the PB head position explain my problem - and if so how can it be adjusted? I don't see how I could have changed anything with that plate when changing the roller, so I'm wondering if I'm not looking in a completely wrong direction.
Looking at the video I see nothing wrong, but question still remains: does the white plastic slider move the head bridge into fully extended position ? Because you may have a problem with the plastic slider/play button not fully latching. The fact the bridge is moving freely is just half of the check. Another thing to check is to put the unit in play and retract the roller from the capstan: see how much force it takes. Then also try to stall the roller without retracting it. Are you able to put load on the motor by doing that or the roller is just slipping ? This may suggest something else: that on the reference unit the head bridge is not fully retracting to that stop point, hence why roller is closer to the capstan. If that's the case, the reference unit has a problem not the other way round. In regard to the plate that holds the head spring, that can be moved forward: just get the screw a little loose, push it forward and tighten the screw back. However that would affect head bridge position only when the door is installed and only in stop position, not with door removed. Also, have you checked the motor is turning freely in both directions ?
A big thank you! to @Valentin who eventually checked my unit and fixed it! He fixed the following root causes: The small reel gear was not pressed in far enough. Shaft was also dirty of probably some old belt residue. The takeup reel support was broken. Was cleaned and glued to the metal chassis. Then, Valentin also adjusted the following elements, to make the unit smooth as butter: Motor spindle did have some residue on it. Auto-stop levers were cleaned of any oil as they were moving a bit hard. Center gear was adjusted to reduce wobble. Recorded a full cassette today for the first time in almost 35 years - it just rocks! Thanks again!
I had to look all around this model to find the correct model number to make sure it was the right one for this thread. This is just a picture of mine. Nothing more. Don't read anything into it I will say that I was looking for the latest information on this wm-d3 but this was the first thread I came to so here's a picture. Nothing more, nothing less.
