Advice needed: Startup sequence changed, slim metal EX808, won’t run.

For information: the EX808 and EX502/508 (and the donor EX707) motor are each built slightly different than motor in tutorial, but I don't know if it will make any difference:


Question about windings on the PC board: are they printed on both sides of the PC board? or just top? was wondering if there is a way to keep from damaging the traces for the windings (ex: could you insert very thin mylar to protect?). It seems the only thing keeping the motor in is the PC board? and the vertical play would also be determined by the PC board clearance with the magnets?

I also bought the "cuticle trim tool" to use with removal of plastic split keepers: the first one was damaged due to the v-shape, so I flattened slightly and will dull some of the edge...

 

There are 5 or 6 (possibly more) slightly different motors across the EX/FX series, but all are built the same. The main difference is where the connector is located and the number of pins. Some have 4 pins, some have 8 pins (like WM-EX5 for example).
From EX502 and 808 the only difference that I see if how the motor is held down on the chassis: one has 2 wings with screws, the other has screws on the back. As said, there are many variations unfortaunately.
But that will only matter when motor has lateral play and you need to replace it.

In regard to PCB, there are coils on both sides and vias connecting them. In practice, you can even use a pair of tweezers or sharp metal tool unless you only apply force above the PCB and not on the PCB itself.
By given the motor that I diassembled runned, I think I did not produce any damage to it. However on a good one I would pay more attention to how I remove the glue. I recommend trying to remove glue with something plastic, that way there's no risk at all.

And yes, the vertical play is determined by the clearance between bottom magnet and PCB.

 

made a sketch of cross section, walkman EX DC pancake motor: not to scale of course:


the central chromed pin rests on a steel(?) pin mounted inside bottom bushing in pan, similar to a turntable spindle bearing,
Wonder if motor parts are interchangeable, which would allow you to change pan to change mounting? Esample i have a donor EX502, couldn't use motor in EX808, but if i could use the pan from the donor EX707, i could convert spare motor to fit EX808...

 

The central pin rests on a piece of hard plastic (transparent) which you will be able to see from the other side.

I think motor parts are interchanghable, but not all of them. Rotor is probably the same in all of them (including the top magnet), but bottom pan and circuit board are likely to be different.
PCB will have a different shape and contacts in a different position depending on the type of bottom pan used.

The problem is exactly the bottom pan, cause it's that brass bushing that wears out, since it's a soft metal. The central pin is steel and it's much harder.

The PCB can be re-desinged and re-manufactured, it will cost a bit more since it's a very thin one, but it's doable if really needed. But I don't think that will ever be a problem if glue is removed carefully.

 

Question: if the square drive belt is "twisted" what impact will this have on wow and flutter? I don't remember confirming the belt was not "twisted"...

 

I don't think that will have any impact on the wow&flutter. I like to put it untwisted because it looks good and that's the way it should be. In many cases it will untwist itself after a period of use anyway.

 

Sorry I have not been able to access the S2Go servers for a week or so... just got on tonight...

I am still waiting for my new plastic spudger tools to arrive, but i opened the unit and marked a black line on both brass pulleys, and noticed odd behavior. in the below photo, I marked one direction FWD and the other REV: in the REV direction, the black dots stay in almost the same relative position during rotation.

But in the FWD (corrected) direction, the pulley on the right seems to slip significantly: the unit has the "correct" new belt from Marian, 58mm diameter. Is there something in the mechanism that would commonly cause "drag" or need lubrication?


I plan to open the motor to try lubrication when the tools arrive.

 

Since you lubricated every rotating part, what else can be causing it ? If something is dragging, you will feel it by hand.
Does that small idler move back and forth when mechanism operated or not ?
On some WM-EXs, that small idler moves out a bit during mech engagement to tension the belt. It also move out during FF/REW, as these require higher torque.

Does the belt look tight when operating in the problematic direction (it's not clear which one it is since you named them both REV) ?

 

Sorry Valentin, I read your message 10 times before I see what I did wrong... the second paragraph should show "FWD", not "REV" (I corrected this in the post).

There seems to be little or no slippage in the direction marked "REW", and the belt is uniformly tight during constant rotation,
but in the direction marked "FWD", very quickly it slips significantly, like something on one of the pulleys is dragging badly.
In the REW direction, the belt appears perfectly tight all the time, but in the FWD direction, the belt immediately after the motor pulley "bows out" slightly, like it is under high loading...
I will look again manually to see if I can "feel" what is causing the load increase...