This thread will cover what causes the tac-tac sound on this walkman and other models which use a similar mechanism and explain how to fix it. Models with this mech: WM-EX3, WM-EX5, WM-EX7, WM-EX9, WM-EX900, WM-EX527, WM-EX550/552, WM-EX560/EX562, WM-EX570, WM-EX610, WM-EX615, WM-EX651, WM-EX660/662, WM-EX631, WM-EX650/652/654, WM-EX655/668, WM-EX670, WM-EX672, WM-EX674, WM-EX677, WM-EX678, WM-EX910, WM-EX921, WM-GX688, WM-GX670, WM-GX788 Units other than those mentioned have this type of clutch gear, so if anyone knows which ones, please let me know so I can edit and add all the relevant models. First, keep in mind when buying one of these units that there is a 50% chance that it will have this problem, even if the seller does not tell so. When I bought my unit (was sold as functional with a new belt) I was very excited that it would not have this problem. However, that proved not to be the case. The first time I opened the unit and removed the PCB saw nothing that could explain the sound. But on a second inspection I saw a hairline crack on the center clutch gear. A tac-tac sound can be caused by 3 main things: 1. The clutch gear itself being cracked (which is the most common one). This will generate a low frequency tac-tac, about once every 2 seconds. 2. The small gear on the flywheel which drives the geartrain. This will generate a high frequncey tac-tac, many times/second. 3. The idler gear between the flywheel and clutch. This is caused by the gear being warped and it's very rare. This will generate a tac-tac very similar to the clutch itself, only way to to diagnose it is by looking at the clutch itself. If clutch is intact, then this gear is the problem. Note both 2 and 3 will need a donor unit with same mechanism to be solved. The bad news is you won't find a new redesigned gear and the only way to fix it is buying a donor unit (cheaper model with same mech) and hoping the donor unit will not have the same problem. I bought 2 donor units and only one of them had a good clutch gear, so keep that in mind. *The PCB depicted here is from the WM-EX5. The joints that need to be desoldered will vary on different units. You need to disassemble the unit completely in order to replace the clutch gear: take the back cover off, take the door off, the plastic bezel off and then the PCB. The PCB has a lot of solder joints that need desolering before removing it: the battery terminals, the motor terminals, the solenoid, EQ switch and lateral switches (not visible, but marked in the picture). The head flex cable also needs to be removed. After replacing the gear, I suggest the following in order to reduce the chance of another gear failure: - keep the unit at room temperature to avoid any expansion of the metal disc of the clutch, that could break the gear. - do not use the FF/REW, as it puts a high load on the gear and also comes suddenly to a full stop at the end, putting a lot of force on the gear.
I didn't even knew a WM-EX2 existed until now. Checked the service manual and it uses a different clutch system (2 gears in the center instead of one and of smaller diameter than the driving one) than the problematic one mentioned here.
An update: seems that someone has manufactured a replacement gear for these models: https://www.ebay.com/itm/324804973495 Attached a picture in case the listing will change or be updated with different keywords. Note that this gear is still a press fit type and will be prone to cracking as well, so the recommendations in first post are still valid , even if using this type of gear. The advantage of a new one is being new, it will take a lot more time until the POM material shrinks, compared to an old one. However, storage conditions seem to have a significant impact, as there are still plenty of these with intact original gear.
I'm not sure it would be possible, but what about repairing this clutch gear in the style of WM-150 clutch gear repair? I understand it would be temporary, but that would be saving broken part and not making more walkman's for parts I just saw the price of that replacement part and sorry but 60$ for a gear (with shipping) is more expensive that gear for DD's. Hardly worth imho. 5 months ago I've bought Aiwa PC202 in working state (will need to change caps one day but more as precaution that real need) for less.
@Raul I'm not sure, as in this case the plastic gear is glued onto a metal disc (as clutch is magnetic). The replacement part is expensive, but for some in the series (like EX3, EX5, EX7, EX9, EX900) it might be worth it as the walkmans themselves are valuable. At the end of the day, it really depends how readily available donors will be in the future. It's always good to have more than one choice, that's why I posted that ebay gear. My assumption is the gear is more expensive than DD because the seller only sold a handful of those gears, while DD ones have been sold in the hunderds mark (probably close to 1000 or even more), so the price per piece can be lower in this case.
I should have written that it's not worth it maybe except that more expensive models you've mentioned. Still, it's only one part of the walkman and it cost imho too much. Yeah, price to demand ratio is poor, and as we are close to peak of Walkman comeback with more and more of them in bad shape with absurd prices (as much as I love Sony WM-501 I don't think that not working unit is worth half and more the price when it was new, boxed and with warranty) some models will just fade as not worth repair. DD's are worth it, but EX3, or EX9xx? They are sonically good, but nowhere great/best.
I'm on the same page with you, but wanted to give some credit to someone that has put in the effort to design and produce such a gear in the first place. At this point in time, even for the more expensive models, a donor unit will be the cheaper option. I agree we are likely close to the peak of walkman comeback and at this point in time some sellers do not make distincion between working/non-working/in need of a service because they think they're extremely valuable. This won't go on indefinetely and people will realise (in time) that many walkmans will need more than just a belt (you stated that in another thread). DDs are at least something special in terms of design, it's very different from a typical walkman, have extremely good wow&flutter and sound is also very good. As for EX series, my personal opinion is Panasonic RQ-S/RQ-SX/RQ-X are better than SONY EX in terms of sound quality. MagneticBlood also stated this on the other forum, so I'm certainly not the only one that has this opinion.
Of course I respect people who make parts for Walkmans. Especially when those are better than original, like DD gear or gear for WM-150 siblings. What I don't get is why there is such a problem with sharing some info on TH forum for example. I play with walkmans for about 2 years and there is a lot I don't know about repairs. Most of what I know is either from some tutorials (Marian tutorial how to replace belt in Panasonic RQ-S series for example) or repairing and destroying some walkmans. It hurts me when I brake one that could have been saved. I wish there was tutorial for changing pinch rollers, greasing gears etc. Maybe people who change belt only would do more to revive Walkmans
There are a couple of reasons, although things are getting better, but slowly. - One reason is people who have repaired a lot of walkmans (most have worked in the field back in the day) may not want to share information, because they fear losing potential customers. I personally don't believe this is the case, quite the opposite and I have stated this before. Don't know to what degree this happens, but I would not condemn people doing this. - Another reason may be some just don't bother to take pictures and do a basic edit on them pointing out things. Even tutorials that I did, need significantly more focus than just doing the repair. Like I must pay attention "Did I take a picture at this step ?". If no, I must diassemble again, go back to previous step just to take a picture. If I were to do it on video, good lighting (without shadows) becomes another problem as it will take up working space. Even then, there will be parts of the video that will need to be cut at the end, even if I were to do a timelapse kind of video. This is the reason why I won't do a tutorial for every single model I repair (although I would want to). - A third reason is the lack of willingness to acknowledge these devices do need more elaborate repairs in many cases. Given the increase in interest, sellers will many times try to sell a used device at the price of a serviced one, stating it's no big deal, you just need a new belt. This can mean sometimes a repair/service will be out of the question because all the available money (what people are willing to spend on a particular walkman) has been spent on the walkman itself. An example of the third can be DD series or a D6C. If a seller wants to earn the maximum amount possible, he will hide potential problems (even the fact that DDs have broken center gears) in order to get the maximum amount. Even as of 2022, many people have no idea that DDs have broken center gears and will pay more on a "working" one. There are even sellers that don't know and might assume the tac-tac sound is normal and was like that from factory. This obviously creates the mentality that these devices "just work" and may need a new belt in some cases, but nothing serious. I wish that was the case in real life, but it's not.
I want to share with you another clutch gear, which is much cheaper than the previously mentioned one. Here it is: https://www.ebay.com/itm/314621322942 At this price (25$ with shipping) I think it's worth replacing the gear with a new one instead of one from a donor unit. Why ? Because even the ones from a donor unit won't be perfect having some kind of small crack in it. So for a perfectly working mechanism and lowest wow&flutter (motor should also be lubricated for this) this is the way to go.
What makes the click click sound? I know the cracked gear.. but is it a jump in movement between the teeth or the gear moving, what? Glueing the crack (when its tiny) isn't a fix? I don't have one of these models so I don't know, I'm only asking.
The click click sound is made by the gear tilting when reaching the crack between 2 teeth. So at the point when the crack reaches the driving gear, beacuse the teeth no longer engage correctly with each other (due to the too large gap), the clutch gear tilts to one side for a split second and that's what creates the tac tac sound. Unlike DDs, where the gap is very large, on these WM-EXs it's the tilting itself which generates noise when the gap is very small. Unfortunately I do not have a video illustrating this at the moment, but hope you got an idea of how it happens. Can the gear be fixed ? Not really, because the plastic ring is molded onto a metal disc. The plastic (POM) shrinks and cracks, while the metal remains the same. So fixing it would require to either file the inside of the gear or the metal disc itself in order to accomodate for the shrinked POM material. Not really worth it given the cost of both donor units and a new gear are more than decent. Besides that, the new replacement gear is not a press fit (since it's not molded), so once this repair is done it's not going to fail again.
An update in regard to a gear I have tried myself: https://www.ebay.com/itm/335028384425 Part is very cheap, but do keep in mind most of these will come warped and you will need to bend them back into straight position before glueing them (see pictures attached). In my opinion it's a good overall deal, but you have to consider the extra step needed before istallation.
Thanks for flushing out another option here Valentin. I just ordered one for an EX3. If you don’t mind sharing, what did you do to flatten out the gear? A little heat? Thanks.
I flattened it out by simply bending it in the opposite direction beyond the point it was straight. Done this quite a few times until I was satisfied with the result. Note it needs to be straightened before glueing it to the metal disc. Would not recommend using heat at all because it's likely the material will shrink if you heat it.
