How to lubricate disc-type motor in SONY walkmans

This thread will cover the disassembly and lubrication process of cages disc-type motors used in SONY walkmans.

A short list of walkman using this type of motor:
1. WM-A602/WM-B602/WM-B603/WM-AF604/WM-150/WM-170/WM-F181/WM-190/WM-506/WM-2091/WM-F2095/WM-EX49/WM-EX49C/WM-EX50/WM-FX50
2. WM-701C, WM-702

Similar to the SONY WM-EX/FX series (which has a very similar motor, but not caged), this type of motor is prone to wear and being noisy due to lack of lubrication and improper lubricants used at the factory (very thin coat of grease).
That is why it is recommended to to this when you replace the belt in your walkman, as it is recommended to do a cleaning and re-lubrication of all rotating parts to assure a good wow&flutter figure.

Disassembly of the walkman and taking the motor out is not covered in this thread and it is assumed you have the skills to do that. Otherwise, I do not recommend attempting this repair, as it's pretty high risk.

STEPS:

1. Take the motor out of the chassis.
2. Remove the glue on the edge of motor metal cover. You will need a very sharp tool to remove this glue, as it may be very hard in some cases. I recommend removing all glue before attempting to remove the cover, otherwise you will bend it.
3. Remove the metal cover.
4. Remove the top metal disc (not shown in pictures). Use a plastic tool to remove the metal disc.
5. Remove the PCB containing the coils
6. Remove the rotor.
7. Clean the shaft and bushing with a cotton swab immersed in IPA.
8. Lubricate the bushing as indicated in picture. Use watch oil to lubricate the inside of the bushing and a thin grease (like SW-92SA or similar) to lubricate the top of the bushing.
9. Reassemble. You will need to glue the top cover back. It's enough to do it in 3 or 4 spots, not on the entire length.

NOTE: If you bent the cover, straighten it before re-assembly.

 

Relictor Ring - What is That?!? I almost want to follow your steps and switch from Discmans to Walkmans just for the sake of actually learning something… @Valentin - you are The King!!!

 

The EX/FX motor has magnets on both sides, but that is because the coils themselves are only PCB traces (lower number of turns), thus generating much weaker magnetic field in the EX/FX type.

This is about the only difference compared to this one: https://stereo2go.com/forums/threads/how-to-diassemble-and-lubricate-sony-wm-ex-fx-motor.7940/

As a sidenote, motor used in WM-10 is also of this type, but without a cage (it only has a top thin metal cover hold on with screws).
The difference in WM-10 is that one uses a ball bearing instead of a bushing (which will also need lubrication, as some WM-10 have very noisy motor with bearing noise).

 

Great guide and also do not use too much oil or grease as the motor won't turn properly
Ask me how I know

 

I tried this with my my 2091, the coils are not exposed copper like the one in your post but its pretty much the same, probably a MK2 of the WM10 motor.
After careful reassembly, its now locked SOLID
I did however buy mine with corrosion damage from a battery so some rubbish may have leaked into it that I cant quite see...
Will try again sometime soon to fix it if I cant get hold of a replacement...

 

If it's locked solid, it means the rotor is coming into contact with the coils. The coils assembly or PCB in the case of EX/FX type motor needs to sit flush with the case,
as the clearances are very tight (0.2mm-0.25mm) and any slight misalignment will result either in friction between rotor and coils or complete lockup.

The WM-10 motor is slightly different in design as instead of a bushing it has a ball bearing. However the coils are exposed copper, not just traces on a PCB.

Please provide a picture witht the 2091, as it might have a different type of motor than all 3 types we are talking about here.

 

Stolen from another thread on this forum...[GALLERY=media, 1943]Motor by Wombat posted Jul 29, 2022 at 11:02 AM[/GALLERY]

 

Yes, I do know this one, WM-2091 being in the same series as WM-150, WM-B603.
This type of motor is the same as the one described in this thread in terms of how it is disassembled, but the coils are on a PCB, like the EX/FX type.

It has nothing to do with the WM-10/20 and alike, those are different: ball bearing instead of bushing and magnet (rotor) is only on bottom side, as it has to be very compact.

 

Can anyone show the belt wiring diagram for the WM-A602/B602?

 

Here you have the belt routing, which is the same on all models with this mechanism:
WM-A602/WM-B602/WM-B603/WM-AF604/WM-150/WM-170/WM-F181/WM-190/WM-506/WM-2091/WM-F2095/WM-EX48/WM-EX49/WM-EX49C/WM-EX50/WM-FX50/WM-GX51:

 

Thanks a lot! you confirmed my guess

 

I wonder the purpose of the black plastic pulley at the bottom left.?

 

Small black pulley is for routing purposes only, it doesn't drive anything. Many mechanisms have such an "idler" pulley.

 

change belt and capacitor

 

Hi Valentin,

After a full restore (gear, caps, belt, etc) of a WM-AF604 and WM-2091, I decided to go ahead with the motor lube on the AF604. I uploaded a video with the results here:

The AF604 is quieter for sure but still can be heard from across a quiet room. I had two questions I would really appreciate your experience with: 1) Should the AF604 be even quieter than this or is this now just normal? Other Walkman models vary, but some are quieter. 2) For the 2091, is this the typical noise you would hear with a motor needing a lube? If so, I will go ahead with this one as well.

Thank you so much.

These models are good looking, but very challenging to repair! Every electrolytic cap needed replacement on both.

Jehr

 

The AF604 sounds about right. Given it's a recording, can't really assses the exact loudness, but the tonality and loudness seem to be more or less where it should be.
What I suggest is just use it for some time, as these motors tend be become quieter after a "break-in" period. It should get to a point where it becomes barely audible across a quiet room.

The WM-2091 is really loud, would definetely go ahead and re-lubricaite it. But also check the sideplay of the shaft, because at this point it's possible you also have some wear in the bushing.
Another thing to check is if the rotor doesn't touch the coils or case. Keep in mind if there is wear in the bushing, the rotor will sit at an angle when belt is installed, so clearances will become smaller.
Also be sure to clean the old grease from the shaft and bushing well before re-lubing.

Haven't studied the noise before/after extensively (I always lube these motors, many times before first power on), but what I can say is this noise is not normal.

Indeed these series of walkmans (with WM-150 type mechanism) are not the quietest, but this is also because the motor drive circuit not just motor itself. WM-700 series are much quieter, despite using an almost identical motor.

 

Thank you Valentin, I appreciate your insight on this topic. I will go ahead and lubricate the motor on the 2091 this week and will try to post a before and after sound check! Thanks again.

 

Full motor lubrication completed… see before and after here:

I don’t think there is any significant improvement noted but I will play it for a while and see how things go. I did get a significant improvement on the Af 604 but maybe something else is at play here on the 2091. There is a fairly high pitched whine that I can only assume is coming from the motor. Thank you!

 

Maybe of interest due to being related, is ASB Custom's recent video on re-winding motor coils.
His videos are really informative and his narration is also clear and it's like listening to Bob Ross...but with tapedecks! lol

 

@Jehr It's to be noted I don't see this lubrication as a cure to wear or other motor problems, but rather as a maintenance item.
Listening more carefully to both recordings, I realise the 2091 isn't that bad, it just seemed bad initially when compared to the AF604.
So at the end of day, if the w&f is within reasonable limits, that noise can be considered ok. If it becomes quieter over time, that's a bonus.