How to lubricate disc-type motor in SONY walkmans

Thank you Valentin, I appreciate you taking the time to listen. It is probably as good as it will get at this point so I’ll move on!

 

Hi Valentin,

I was under the impression that injecting watch oil through the plastic membrane on the other side of the motor would lubricate the shaft. Am I wrong? See attached pic.

That part of the motor is even made easily accessible from the outside without having to disassemble the Walkman. If not for lubrication, then what would be the purpose of making it easily accessible?

 

That plastic membrane is part of the bushing, it's there to keep the motor shaft at the correct height.
Don't know why on some motors it is made of transparent plastic, but it's not for oiling.
Piercing it to add oil will alter its geometry and also oil will tend to sip out through that hole.

Unfortunately there is no other way to oil the motor apart from disassembly.

 

Thank you! I successfully disassembled the motor of another unit (a Sony WM-600 Walkman) and lubricated it with watch oil, following your tutorial. I carefully removed the glue from the edges of the PCB using an X-Acto knife, which allowed the PCB to come off easily. When reassembling, I used tiny drops of PVA glue, which hold the PCB securely while remaining easy to remove in the future. It took a lot of patience, but it was worth it! A strong magnifying lens was invaluable in helping me avoid cutting the PCB traces.

 

Quick question here. I have two WM-10RVs that I am working on. I disassembled the motors from the top but upon re-assembly, they both make very faint scratching noises when I spin them and there seems to be more friction that before I lubed them. Is there a trick to re-assembly that I may be missing?

 

Noticed that faint scratching noise in WM-700 series motors myself, it's audible when the motor comes down to a halt.
When it's rotated as higher speed by hand, it's not noticeable. Not sure where it comes from, but seen it so many motors incline to believe it's normal.
What I'm reffering to is also not related to lubrication, this noise existed before/after.

As for the friction, it's normal to be a tiny bit more friction because of the oil's surface tension.
If after rotating the motor by hand it doesn't stop immdiately, it's fine.

 

Hi @Valentin

I'm trying to disassemble a (spare) WM-150 motor to see if I can potentially reduce the noise it makes when spinning, but I simply cannot figure out how I am supposed to remove the cover? There is no gap whatsoever that even a craft knife can penetrate around the edge:

 

@djsubtronic What you show here is not a brushless 3 phase disc motor, but a DC motor.
Opening it is completely different and more risky than the type I showed.
Wasn't aware WM-150 units also featured this type of motor. Do you happen to know the serial of the walkman it was installed on ?

To disassemble a brushed DC motor you first need to remove the pulley, then remove rotor + brushes as a complete assy (think back cover is part of that asstly) othewise brushes can be damaged.
Same goes for putting it back.
The back case is stamped in a couple of points. Generally I recommend against opening such motors.

 

@Valentin Thanks for the reply, I assumed these were brushless as well. I can't remember the serial number anymore as I have a lot of these motors that I already took out. Of all the WM-150s I have had, has either one of the below motors:



There are ones with thicker red+black wires soldered to the outside - I found these mostly on units from Japan/later units. Then there are the thinner red+blue wires that go into the housing. I found these mostly on UK/older units. The blue ones tend to run much quieter. I have yet to see a WM-150 (out of at least 11 or 12 units I have worked on) that has not had one of these two variant of motor. The WM-150 doesn't have a servo like the WM-2091 version for example.

 

Indeed all WM-150 use this type of motor. This particular unit is different than others using this mech.
I was so used to the WM-150 type mechanism using the brushless one that I thought all of them were the same.
On this recommend only oil the top bushing without disassemblying the motor.

These aren't brushless. You can tell by the shape of the back cover and housing and fact these only have 2 wires.
3 phase brushless have 4 wires: a B+, U, V, W (the 3 phases). Some can have more if the unit has separate windings for high speed FF/REW.