Pioneer- PL570. Rotation rub fixed. Now Antiskate not working.

[Old Guy8]

View attachment 954328 I have a noise when platter rotates. Taken apart I don't find any evidence of interferance rubbing. The spindle and bronze bushing does not show much wear. A 5mm bearing ball rides in ground center at bottom of spindle. It sits against nylon thrust plate. Plate has groove for seal.
The thrust plate has a dimple from wear at center. I'm considering polishing washer entire surface to remove dimple.
Does anyone have experience with curing rotation noise and vibration on these Pioneers? Or similar? Stylus easily picks up noise with rotation.
Also, the bearing was dry. No sign of grease or oil lub. Normal? I'm thinking the seal was there to hold oil in.

Edit: See post #8. After thrust washer polished still issue.

 

[marcmorin]

I'm thinking, the oil out-gassed over the years. noise is probably due to that. Regarding dimple: check the end of the spindle for a wear pattern, 10X should be fine, 30X better. If the spindle end looks fine with no wear patterns, leave the dimple in the thrust plate alone. Because, if the lack of lubrication has wallered the top of the main well sleeve, a new flat surface for the spindle may allow the thrust end to orbit a bit. If the dimple is just a dimple, it will hold the thrust end centered in place.

 

[Nakdoc]

Do not polish the thrust plate as it will reduce the space between platter and motor, likely making the problem worse! Flip the thrust plate over and see if the rubbing quits. If you can't flip it, add a thin layer of something like 6 layers of foil beneath the plate to raise it slightly.

 

[Old Guy8]

I'm thinking, the oil out-gassed over the years. noise is probably due to that. Regarding dimple: check the end of the spindle for a wear pattern, 10X should be fine, 30X better. If the spindle end looks fine with no wear patterns, leave the dimple in the thrust plate alone. Because, if the lack of lubrication has wallered the top of the main well sleeve, a new flat surface for the spindle may allow the thrust end to orbit a bit. If the dimple is just a dimple, it will hold the thrust end centered in place.

Marcmorin,
I've inspected bearing ball and center of spindle end with 8.5x loop that I have. Can't see any wear on either. The thrust washer is just held with three screws. There is no precision locating. So if I put it back as is, without removing dimple, the dimple will most likely now be off-center and cause wobble vibration.
Maybe, also replace oring. Add a little oil. Too much and it will overflow into motor windings. Maybe grease farther up spindle for bushing.
Just thinking out loud.

 

[Old Guy8]

Do not polish the thrust plate as it will reduce the space between platter and motor, likely making the problem worse! Flip the thrust plate over and see if the rubbing quits. If you can't flip it, add a thin layer of something like 6 layers of foil beneath the plate to raise it slightly.

Nakdoc,
I could flip the thrust washer over, for a trial, to hear if noise quits. But for permanent solution would loose the seal groove.
If I polish the ENTIRE surface of the washer, the position of thrust washer will stay flush to mounting surface. Should be same as when it was manufactured. Unless I'm missing something. When I use the word dimple I'm trying to discribe a concave spot. Not raised.
It's more difficult to visualize from pics instead of in person.

 

[Old Guy8]

The wear dimple measures only .003" deep with dial indicator.
What would be a good method of polishing the entire surface smooth?
I have some aluminum metal polish. Not sure how much rubbing to remove .003". And don't want to leave anything abrasive imbeded in the delrin nylon.
I'll start with the aluminum polish. Use a piece of glass as surface to rub thrust washer against. See what that does. I also have plastic headlamp lense polish kit.

 

[Old Guy8]

Do not polish the thrust plsurfaceit will reduce the space between platter and motor, likely making the problem worse! Flip the thrust plate over and see if the rubbing quits. If you can't flip it, add a thin layer of something like 6 layers of foil beneath the plate to raise it slightly.

Nakdoc,
I was confused by what you ment, useeing foil shims. The bottom surface of thrust washer does not locate it. It bolts from underneath motor. The washer top surface mounts against motor housing.

 

[Old Guy8]

Polished thrustwasher with 400 paper til wear dimple gone. Then 800 and metal polish. Replaced 3/4"x3/32" oring. Will try a 20 weight synthetic oil without overfilling on to motor coils.

 

[Old Guy8]

Thrust washer was polished. Wear dimple is gone from it.
Reassembled thrustwasher and bottom cover.
Flipped table right side up. Reassembled spindle with bearing ball at bottom, after dab of grease holding to spindle end and adding oil to bushing cavity.
Still have rubbing at constant place on EVERY SECOND rotation? I am confused on this one. Don't see any interferance points yet. Rubbing can be felt turning spindle by hand, with platter off.

 

[mcdan]

Just a thought. Have you "cleaned" the magnet with masking tape to be sure there are no metal filings causing the friction?
Dan

 

[freQ(*)Oddio]

with and without the platter this happens, ? ive had platter, or the magnet slightly touch on a turn

 

[freQ(*)Oddio]

magnet housing bent and touching a coil winding

 

[Old Guy8]

Just a thought. Have you "cleaned" the magnet with masking tape to be sure there are no metal filings causing the friction?
Dan

No.
Have not tried that. It rubs in same spot, usuallyon every second rotation.

 

[Old Guy8]

magnet housing bent and touching a coil winding

I have felt and heard rub while rotating spindle by hand, without platter.

I reinstalled spindle and platter again after adding oil. After pressing and perging most of the air out. Spindle was low enough to spin at constant speed. The noise was gone. Then a couple minutes later it is back. I think the last of air escaping brought it low enough to rub.
If I can locate a 6mm ball to try, replacing 5mm. Will see if spindle clears and still low enough to run at correct speed. Or, if can find other bearing ball sizes just over 5mm. Maybe 7/32".
Thoughts?

Edit: My first rub suspect is the top of the nylon tubing built into motor. It could be rubbing and not leave marks.Going to put Dykem nondrying bluing on underside of spindle housing. See if tubing marks it. Is not source of rubbing.
Having trouble finding slightly larger size bearing ball locally. Ordered metric assortment with 5.5and 6mm sizes for trial.

Another issue to fix:
Also 470uf cap is leaking. Have to figure out spec and order one.
Edit: May be just excess glue, and not corrosion.

 

[revox-b77]

Shim the whole trust plate .003 higher by adding shim stock underneath as mentioned in post #3.

 

[Old Guy8]

Shim the whole trust plate .300 higher by adding shim stock underneath as mentioned in post #3.

In post #1, The first and third pics show the bushing cavity from the bottom of the turntable. I tried to explain in post #7. The thrustwasher mounts to it with steel plate over it. So when the turntable is upright, any shims under it do nothing and a washer shape shim on top of washer would lower the thrustwasher and spindle. I could have done better with explaining early on.
If I had a lathe, could make a new thrustwasher shape extended into cavity, to raise spindle.

 

[ghazzer]

Old Guy: Thanks for you carefully worded documentary - I am learning more about the innards of this TT.

Did you find the info you wanted about the 470µƒ cap?

 

[Old Guy8]

Old Guy: Thanks for you carefully wordvoltageumentary - I am learning more about the innards of this TT.

Did you find the info you wanted about the 470µƒ cap?

Have not found the info on the 470uf cap yet. But a replacement will likely be larger voltage rating and bigger. But I'll figure that out.
I got an assortment of hard mm bearing balls in half mm increments on Ebay. Could not find or cheaply order from local bearing distributors. I'll try a 5.5 mm when I can. (Had a flood in basement from rainstorm this week. So prioritys change.)
Been trying to document my repair adventure for others. Because of minimum of info I've found. Posting pics as I go. The manual says nothing about lubrication of spindle. I just assume the oring in thrust washer and extended plastic tube above bushing are there for a reason.

 

[bberkom]

I have felt and heard rub while rotating spindle by hand, without platter.

I reinstalled spindle and platter again after adding oil. After pressing and perging most of the air out. Spindle was low enough to spin at constant speed. The noise was gone. Then a couple minutes later it is back. I think the last of air escaping brought it low enough to rub.
If I can locate a 6mm ball to try, replacing 5mm. Will see if spindle clears and still low enough to run at correct speed. Or, if can find other bearing ball sizes just over 5mm. Maybe 7/32".
Thoughts?

Edit: My first rub suspect is the top of the nylon tubing built into motor. It could be rubbing and not leave marks.Going to put Dykem nondrying bluing on underside of spindle housing. See if tubing marks it. Is not source of rubbing.
Having trouble finding slightly larger size bearing ball locally. Ordered metric assortment with 5.5and 6mm sizes for trial.

Another issue to fix:
Also 470uf cap is leaking. Have to figure out spec and order one.View attachment 957205View attachment 957206

That looks like glue to hold the larger 470uf cap in place, not capacitor leakage. See this kind of glue a lot in Sansui and pioneer amps. It can be corrosive, but not sure about the glue used here.

 

[Old Guy8]

That looks like glue to hold the larger 470uf cap in place, not capacitor leakage. See this kind of glue a lot in Sansui and pioneer amps. It can be corrosive, but not sure about the glue used here.

Thanks for your info. I'm more comfortable with mechanical over electrical issues. I'll look closely at it.