It is actually not a walkman, but a mono recorder, but it has auto-reverse, it uses a tape transport similar to other Sony walkman, it has an LCD display and logic transport buttons very nicely laid out. I bought one from a flea market and it had a melted belt. I thoroughly cleaned it, replace the belt, and it is back to life. It has two nice brass flywheels and while the REV flywheel is free to rotate, the FWD flywheel also drives the take-up spool. As a consequence, W&F in FWD direction is much higher than in REV direction ... Is that a clutch problem ? Is that a known issue of this type of recorder ?
This is the recorder itself with the LCD display The cassette well with the head/pinch roller assembly. To note the head is stereo even if the recorder is mono; the R ans L channels are connected to a common input so it is really mono; having auto-reverese it has two erase heads beside the main head. It also has a proper bias oscillator, not permanent magnets and DC bias The interior with the cover removed, lots of flat cables and all tiny SMD components. Two nice brass flywheels of different size which rotates at different speed to avoid resonance. The tape transport: the right flywheel is responsible for the REV direction while the left one for the FWD. This transport does not use a solenoid to change mode, instead it reverses motor rotation to engage the leftmost black cam gear to move levers and engage the correct mode. To be noted the rotation sensor: it is not optical but rather magnetic, with a permanent magnet attached to a gear. The recorder is powered by either a gumstick rechargeable battery or two AAA batteries connected in parallel. Overall a nice construction, it's a pity FWD direction has audible W&F.
It looks like one of the EX5yy or EX6yy mechanisms to me. Except for the long motor ribbon cable, the PCB, cam gear, idler, head mounting, and 2 brass flywheels seem very familiar.
I found a very similar device, the WM-EX606. Search for WM-EX606 PCB on Google, you’ll quickly find the photo below:
Yep, same tape transport, I downloaded the service manual and indeed the WM-606 uses the same mech as the TCM-80V. There are minor differences (two missing washers and obviously no erase heads) so that Sony is using a different tape mechanism code, but 99% of it is identical. I was quite sure it was derived from a walkman (you do not design a brand new transport just for a mono recorder), but all my Sony walkman's use different transports. I have removed the two aforementioned washers which are on the capstans them-self (paper-thin white plastic washers just below the actual washer/stopper) and were disintegrating. It might have improved W&F, I need to do more tests. Maybe due to age, the motor is not totally silent too: on a walkman is not an issue at all, but for a recorder, it gets captured by the mic. The motor is sealed, there is no way to add even a tiny drop of oil.
@enryfox I would take all those gears out of the mechanism, clean the shafts and inside holes of gears and then relubricate everything with oil. It's something that I tend to do, as sometimes they use grease from the factory, which creates a significant amount of drag, especially if it has hardened over time. If the table reels can be easily separated from the driving gears, those are also worth cleaning and relubricating. Doing this doesn't guarantee an improvement over the wow&flutter figure, but it's worth doing anyway in my opinion. On a mechanism like this, I would expect the side that drives the table reels to have a little bit higher wow&flutter, but not to the point where on forward it's audible and on reverse not audible.
@Valentin, I had thought about removing all gears to clean and inspect them, but several are just clipped in place without C clip and they need considerable force to be removed with the risk of either bending or breaking the retaining clips. I checked very carefully with magnifying glasses and all gears are very clean. As for lubrication, this kind of transport with plastic gears onto metal shaft does not requires lubrications at all: the POM plastic material is slippery on its own and adding oil would just just create clogging with dirt and other debris. I use oil only in metal bearing of motors or capstans (watch oil which is not supposed to dry in years), because with plastic there is also high chance that over time the mineral oil will degrade the plastic. This type of transport has grease only under the two silver metal levers that control the head/pinch roller assembly and engage the clutch in play mode; there I added new neutral grease specific for plastic to minimise friction. My rule of thumb is to add grease only if there are already traces of it from the factory; years ago I tended to grease everything assuming it would make gears runs smoother but indeed in some cases it just increased friction on the shaft. After the last clean-up, W&F has improved in FWD direction, it is now in an acceptable range for a voice recorder. In my (limited) experience, Sony belt driven walkman's does not have great W&F to begin with; this transport has nice brass flywheels versus pure plastic of later WM-EX67x models and that is a plus; but the overall mass is still not enough to have good W&F.
I agree with the fact that grease should only be added where it was from the factory. Have seen a YouTube channel (LivingAnalog), in which the guy greases everything for the sake if it, including pinch roller shafts. Really didn't like it, because people take him as an expert (a statement made by someone on the forum on private message). He also uses grease (which is thick), where oil should (and was used at the factory) be used instead. In regard to plastic gears, if they're dry from the factory (that would be the best case scenario) of course leaving them dry is a good option. That's not always the case though, in some cases requiring at least a cleaning (because of hardened grease on shafts). One example is the TCD-D3/D7/D8 DAT walkmans that have a lot of issues because of dried grease on plastic gears that run on metal shafts. Another would be the Sony WM-DX100 I recently repaired, where the gears were hard to turn by hand. Given what you say, that's not the case with this particular model. That's lucky for you, because those gears are not that easy to take out (on a second look at it), as you state yourself. Good watch oil (like Moebius 9010) is compatible with plastic (stated in its datasheet), so I don't worry about using such oil on plastic parts. What figure of wow&flutter do you get ? I'm curious because I started a thread some time ago for this exact reason: determining how much is acceptable on a belt driven walkman. Opinions vary between 0.15% WRMS to 0.3% WRMS. While above 0.3% WRMS is clearly in the unacceptable range, 0.15% is a figure I'm not sure is obtainable on all walkmans. Of course, it would be nice to take that as a golden standard, but if it cannot be achieved in practice (at least not on a significant number of devices), it's hopeless to do so. My experience says indeed belt driven walkmans (not just Sony, although these may indeed not be the best) do not have the best w&f figures out there.
The logic of when grease was applied in the factory is something that is sometime beyond me: the POM plastic used in transport like the TCM-80V is very glossy and slippery on its own so it hardly needs lubrication. But in other case it just seems random; I like to repair CD players too and Sony used a very similar CD drawer mechanism throughout the 80's and 90's: some of those are completely dry other have traces of white grease. Same material, same mechanism. I do not have a proper tape to measure W&F so I mostly go by ears. W&F is almost never specified in walkman except in the DD where is indicated as 0.13/0.08 % depending on the standard used. Belt driven walkman can never get to those figures; I'm very sensitive to pitch fluctuation and I can say that in all my walkman's (but DD's) I can always hear W&F if the "right" instruments is played (e.g. piano, harpsichord or little bells); pop music is more forgiving for W&F and I'm pretty happy with the Panasonic RQ-X11 I use as a daily driver. What I can say in defence of belt driven walkman is that W&F is minimised when the tape transport is in perfect shape, something that at 20/25 years of age is difficult to get: worn bearings (capstan and motor), slightly shrunken plastic gears all are detrimental for W&F so I do not expect them to sound like when they were new. As for a W&F threshold, to me the less the better, but I'm happy with the typical figure of a tape deck.
