SONY TPS-L2/WM-3 restoration tutorial (mechanical)

The thread covers the restoration of a typical TPS-L2/WM-3, but there are other potential problems that are not described in detail here, because they're rare and the solution may depend on the particular walkman being repaired. Only mechanical restoration is covered here.
Capacitors do sometimes go bad in the WM-3 (the TPS-L2 uses tantalums which don't go bad), causing issues like no sound on one channel, sound coming up with delay on one channel.
If that happens, it is obviously recommended to replace all capacitors. It's also important to use good quality caps like Nichicon/Panasonic, not generic Chinese ones.
In my experience, most WM-3s do not have problems with capacitors and a full recap is usually not needed. Of course, there is nothing wrong if you want to replace them anyway, just use quality ones.

Broken clutch gear fix: https://stereo2go.com/forums/threads/tps-l2-broken-clutch-gear.9534/

NOTE: Some of the WM-3s and TPS-L2s might have a seized motor, due to moisture. If the motor does not turn when powering on, check if it rotates freely.
The lubrication of the motor is covered in this tutorial, because it's something that should be done anyway to bring the wow&flutter down.
The FG coil of the motor can go open due to rust, causing the servo not to function. In this case, the motor will need to be opened to repair it (not covered in this thread).
Motor restoration thread: https://stereo2go.com/forums/threads/wm-3-tps-l2-wm-3-motor-disassembly-and-maintenance.7424/

Parts you will need:
- complete rubber set: https://fixyouraudio.com/product/tps-l2-repair-kit/
- new pinch roller: https://fixyouraudio.com/product/sony-tps-l2-pinch-roller/
- battery door latch: https://www.ebay.com/itm/For-Walkma...latch-Clip-fermeture-trappe-pile/265004855615

A missing battery door latch is common on these units. The 3D printed one will not look identical to the original, but it is more than good enough.
The pinch roller usually needs replacement: if it has cracks, indentations or glaze it should be replaced.

DISASSEMBLY:

1. The plastic back plate needs to come off first. Note that there is a brass sleeve on the screw near the side cover. That is used to align the side to the rest of the case, so do not loose it.
2. Next, the 3 other screws holding the back cover can come out.
3. The cassette door lever needs to come out.
4. Carefully take the back cover off; the battery door will also come off at this point.
5. Take off the side cover (the one with hotline switch), by rotating it.
6. Take off the front panel (note one of the screws is longer).
The volume buttons will come out and the microphone might be stuck to the case. Do not force the front panel out, take it out 1cm or so and pry the microphone with a pair of tweezers.

 

MECHANICAL REPAIR:

NOTE: most pulleys and gears that need to be taken out have black washers. You need to pay attention as they are very important in reduction friction and hence wow&flutter.

Most points indicated here must be lubricated with oil. Avoid using grease in general, because most greases tend to harden over time, especially when the unit is not used for a very long time. I recommend using watch oil, but other general purpose mechanism oils also work.

1. At this point, you can replace the pinch roller.
2. The main PCB needs to be folded over; in order to do that, desolder the 3 marked wires and remove the 2 screws.
3. Now you can remove the flywheel bracket in order to remove the belts: you need to remove 2 screws. Note that the one near the play button is longer.
4. Take out both flywheels. Note that the big one has 2 washers on the shaft. They're very important for wow&flutter, so do not loose them.
5. Take out the black plastic pulley. There is a small white gear below it: remove it.

AUTO-STOP MECHANISM
The auto-stop mechanism is the main source of wow&flutter in this type of mechanism. The cam gear creates an uneven load; because the unit is belt driven, the servo cannot fully compensate for this and the drop in speed is trasmitted to the flywheel and capstan, creating a rhytmic wow once every couple of seconds (when the cam engages). The phenomenon can be attenuated considerably if all the moving parts are lubricated correctly and move freely.

FF/REW MECHANISM
Depending on how the unit was stored and how much it got used over the years, the FF/REW can get completely stuck by old grease. That is why I recommend cleaning all the shafts from old grease and relubricate them with oil. This is not related to the wow&flutter, but it can decrease the winding torque.

BACKTENSION MECHANISM
High backtension is another source of wow&flutter. It is better to be on the low side than too high. Too much backtension will also wear the head more.
The supply reel should have just a little bit of resistance, you should be able to rotate it with a single finger without applying force.
A torque meter is not necessary, as you are not adjusting anything, just making things rotate more freely. Just "adjusting" the backtension can lower the wow&flutter by as much as 0.05% WRMS.

TABLE REELS LUBRICATION
On all SONY cassette machines (including DAT), the table reels tend to turn hard because of old and incorrect grease used. Note that the grease needs to be replaced with oil.
I do not recommend disassembing the table reels, as they can be lubricated without even disassembling the unit.

MOTOR LUBRICATION
The motor is another possible source of wow&flutter. It can create flutter if not lubricated properly. Some of the motors get completely stuck on these units.
There are 2 parts that needs lubrication: the most important is the front bearing, because that's where most of the load is. However, the back bearing can also play a role in wow&flutter. The back bearing is not accesible on these motors, but by removing the red cap you can spray some contact cleaner inside: this will help clean the brushes and commutator, eliminating any imperfect contact that could cause flutter. In addition, contact cleaner can also act as a lubricant on the back bearing. I would not recommend diassembling this motor; although it can be done, being so small increases the risk of damage, especially of the brushes.
NOTE: it is important to run the unit for some time after applying the contact cleaner (an entire side of a cassette is what I would recommend), otherwise it would not work to its full potential.

 

excellent job @Valentin

 

Valentin. Beautifully explained. Photos labelled as well help so much too. Brilliant. Fantastic informative read. I wish I had that much skill and knowledge.

 

I'm glad you find it useful @Derek marshall !

 

Hi, I receive my Uncle's TPS-L2.

I read this guide and a watched a lot of videos. Really impressive.

I bought new belts and for some reason if I install the longer belt as showned in the pictures of thia guide, on the upper side of the motor pulley, the walkman eats all the tape.

In every youtube videos the belt is installed as showned in this pictures.

so the question is what could be the problem?

 

Are you sure your motor wires are soldered correctly ? Maybe your motor is turning backwards. When belt is installed backwards, the takeup reel will turn in reverse, so it will be very obvious you did something wrong.

 

The motor turns clockwise. The walkman was never opened before. At least as I can tell, no signs at all.
Is it possible that the engine had switched polarity as times goes by?
When I opened the case for the first time the motor was not even turning on, so I cleaned it with IPA and keep turning by hand until suddenly started to roll again.

Edit:also, the color wires on the board matches the color in the pictures, red on left, white on right.

 

I reinstall the belt as show in your your picture.
https://flic.kr/p/2n49BYH
And the table reel now spins clockwise as shown in play mode
https://flic.kr/p/2n46G6p

Is this ok? In this setup the tape starts to mess up.

 

Just cheked the WM-3 in my collection: the belt routing is correct as its shown in pictures, however my motor turns counterclockwise.
So the solution is to solder those white and red wires backwards. And to answer your first question, it's not possible that the motor changes direction of rotation in time.
It's either that the motor was replaced at some point and wires were not soldered correctly, or the 2 wire colors are inverted: an error at the factory when assemblying the motor.

At the end of the day it doesn't matter which one it is, the idea is motor should turn counterclockwise.

 

Thanks @Valentin for a great guide. Finally got my hands on a reasonably priced TPS-L2 and got it working nicely with the help of this guide. Surprised by the good sound quality and tape stability. Now I just has to find proper screws for it as it looks like the prvious owner tried a repair and misplaced the original screws.

Thanks to Marian for a quick delivery of the rubber parts.

 

Glad you found the thread useful.
The TPS-L2 and WM-3 are good walkmans, contrary to what some people think.
Very good build quality and even sound despite not the best out there many will be surprised if they would listen to these walkmans.
Given it's the first walkman SONY built and it's made in 1979, I think it's a very good design.

In regard to screws, the ones used on the backplate (where the tone/EQ switch is) and most internal ones can be found in Marian's kit: https://fixyouraudio.com/product/walkman_screws/.
The 3 screws used on the case have smaller heads, but use the same M1.4 thread. These you will have to find in China.

Also added a link in first post to a new thread covering the broken clutch gear problem. Fortunately this is not a very common issue.

 

@Valentin You mentioned up above to use oil instead of grease. BUT in the image below you wrote 'put grease here'. What 'here' means, on the shafts of those brass parts (green arrows) or all the shafts you indicated with arrows?

Also you specifically said to use oil on every shaft.. So, I'm a bit confused - which one is it?

 

I just changed belts, idler rubber and pinch roller - I haven't lubricated anything yet before I get definitive answer on my previous question. But could someone take a look at a video below and at least point me in the right direction regarding the problem.

It was supposed to be playing one of the tracks from Neil Young's Decade album - couldn't tell you which one because even I can't recognize it. Is the problem due to not being lubricated yet?

 

To be clear, by "shaft" I'm reffering to the part of the shaft that rotates inside a bushing. What is marked with red arrows are shafts.
What's marked with green is just a small contact point between the flywheel/capstan assy and the thrust play adjustment screw.
Hence this small contact point is not contained (not inside a bushing) oil will not stay there. It's why grease must be used where green arrows point at.

That's why I specifically marked the green arrows with "Put grease here" and made them a different color to point out there is a difference between that point and what is marked with red arrows.

Looking at the video, that's bad. Speed is low and W&F is all over the place, sign that there's a lot of drag somewhere in the mechanism.
You stated in the beginning motor was seized. Have you lubricated the top bushing of the motor ? If not, start with that.
Also try to rotate the mechanism by hand and identify if there's something which is very hard to turn.

 

Understood. Yeah, the motor was seized and I did lubricate the top bushing with a sewing machine oil (low viscosity). I'll do all the rest tomorrow and let you know what the result is.
What kind of grease do you recommend for the application?

Thanks

 

White lithium grease, although type of grease used on these points isn't critical.

 

@Valentin Lubricated all the stuff from your tutorial and it sounds a bit better now. I have to order 3kHz cassette from fixyouraudio to set proper speed. Please take a look at the video and tell me what you think. Thanks!

 

It is a significant improvement for sure. Would be curious to see a W&F reading.
Note in regard to speed adjustment there's drift in this particular unit, meaning the reading you get the moment you first power on will change after 20-30seconds.
That's why you should do the adjustment and let the unit run 15-20seconds as chances are you will need to readjust it a bit.

 

Thanks! I'll look at it a bit more tomorrow and I'll have to order calibration cassette.
Any suggestions on where to order or is fixyouraudio OK?
Also, I'll upload W&F readings when I get the cassette.

Once again, thank you for the help