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Pioneer pl50 slow speed Help

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Pioneer pl50 slow speed Help

Postby Erock » 23 Feb 2018 16:51

Hello all,

First post thank you in advance.

I have a pl50 wood plinth tt.

It had not been used in many years spindle was free spinning motor running and very old disenegrated belt in pieces.
Ordered a belt pulled main bearing thrust was intact but no good.
Replaced with self in.

Installed belt and read all the info on fast running pl50 but mine was at 28 rpm....

Pulled motor wicks were dry so I opened motor and used 3-1 oil at the bushing wick area reassembled filled oil well and no real change..
I can adjust the belt platter vs Capitan and get it to a max of 31 rpm with it being very sensitive.

Could the .01 if cap causing this?

Any info would be appreciated.

Erik
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Re: Pioneer pl50 slow speed Help

Postby Spinner45 » 23 Feb 2018 18:49

Belt too tight/wrong size will slow down the motor.
Sellers sometimes don't know the critical nuances of determining proper replacement belts.
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Re: Pioneer pl50 slow speed Help

Postby Erock » 23 Feb 2018 19:01

By 3-4 rpm?

Belt measured 35.1

From turntables and needles.

Have read many posts on belt running fast but not slow.....
Most were off less than 1 rpm?
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Re: Pioneer pl50 slow speed Help

Postby Spinner45 » 24 Feb 2018 02:43

Erock wrote:By 3-4 rpm?

Belt measured 35.1

From turntables and needles.

Have read many posts on belt running fast but not slow.....
Most were off less than 1 rpm?


Assuming the motor itself has been lubricated, and in good condition, it IS limited in torque, and when loaded down with a tight belt, it CAN run slow.
I've been through this already, so I can say this with experience.
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Re: Pioneer pl50 slow speed Help

Postby Erock » 24 Feb 2018 03:55

Understand this makes sense.

So would I stretch the belt or would I let it stretch by use?
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Re: Pioneer pl50 slow speed Help

Postby Erock » 24 Feb 2018 04:01

I was talking to a local vintage repair guy I know today and he suggested the same.

Also said that the bronze bearings may not respond to living right away and may need to be removed cleaned etc.

I bought a .01 uf cap today as well.
He stated that even though it's for start up he sees them fail on cassette deck and effect speed.
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Re: Pioneer pl50 slow speed Help

Postby Erock » 25 Feb 2018 04:16

Ok

So pulled the motor cleaned bushings tubes etc.
Polished the spindle and reinstalled.
Used turbine oil and now it's at 34.3!!
The belt I have is the cheaper $17 belt so don't know if that is the issue but it seams to be....
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Re: Pioneer pl50 slow speed Help

Postby Spinner45 » 25 Feb 2018 09:21

Erock wrote:Ok

So pulled the motor cleaned bushings tubes etc.
Polished the spindle and reinstalled.
Used turbine oil and now it's at 34.3!!
The belt I have is the cheaper $17 belt so don't know if that is the issue but it seams to be....


34.3?
How do you determine the "point"?
If you're one of those using some "app" on a phone, give that up.
Use a stobe disk with either a neon or incandecent lamp - the "old school" way.
It's the only "accurate" way.
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Re: Pioneer pl50 slow speed Help

Postby Erock » 25 Feb 2018 18:04

I did use the phone app but used it on my two other tables and they both are around 33.3 so assume it's correct.

Can try another way.
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Re: Pioneer pl50 slow speed Help

Postby Spinner45 » 25 Feb 2018 21:02

The average person can detect a change of pitch of about 5 Hz, depending on frequency.
This is of course being a single continuous tone, not music information.
With that said, I don't think a platter speed of perhaps maybe 31 to 35 RPM fast or slow is a big deal.
Manufacturers of fixed-speed massed-produced turntables allow for some tolerences, always have.
And IF it is a problem to some..... there's a simple solution.... just get a turntable with pitch controls.
Simple.
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Re: Pioneer pl50 slow speed Help

Postby katana1100 » 18 Mar 2018 07:18

As an owner of a pl50, I say that’s too fast.
Look at the little brass thingy that drives the belt- the top
Is shaped like an hour glass. It needs to be at the top, not middle
Part that expands out.
Also at the top of that spindle - it should clean and shiny. If not, clean it as it will
affect the speed.
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Re: Pioneer pl50 slow speed Help

Postby blitzkrieghop » 11 Apr 2018 00:18

Hi I am going through a similar problem with a PLA45D. Be sure the motor mounting screws (mine has three) clamp the rubber conical dampers tightly, between the underside of the table and the screw head. My screws were bottoming out on the screw shoulder with a 1/4” gap that the motor could sag down. This moved the motor pulled away from the speed selector lever and got the two out of line. Initially I was spot on on 33 and around 42.5 on 45. This couple RPMs slow was very noticeable to me, as i have heard a lot of my vinyl on MP3 before, and know what it should sound like. If someone is going in cold to a record then a couple RPM may not do anything to their ears. So I don’t blame you for wanting to get it perfect.

After I got the motor pulley aligned with the lever, it is now 34 for 33 and 46 for 45. I am going to get another belt to see if that makes the difference. I know variations in the belt can affect you by a couple RPM one way or the other so i’d Just recommend trying a couple belts until you get one you like. Otherwise I am not sure how to snow it down. Hard to add friction back in...

Good luck
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Re: Pioneer pl50 slow speed Help

Postby blitzkrieghop » 11 Apr 2018 00:21

I note that to clamp down the rubber mounts I added in a couple rubber washers as spacers, so the screw head would engage prior to bottoming the screw shoulder on the mounting hole. My theory is over time the rubber dried out and lost some height. Not sure exactly how it happened.
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Re: Pioneer pl50 slow speed Help

Postby Spinner45 » 11 Apr 2018 04:11

blitzkrieghop wrote:I note that to clamp down the rubber mounts I added in a couple rubber washers as spacers, so the screw head would engage prior to bottoming the screw shoulder on the mounting hole. My theory is over time the rubber dried out and lost some height. Not sure exactly how it happened.


It's not just a theory, it's a fact of aging.
Rubber/neoprene motor mounts DO deteriorate in time, and the weight of the motor helps the sag.
Best advice, source and replace with new ones.
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