Pioneer PL15D II refurbish

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tetonguy
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Posts: 17
Joined: 11 Jan 2020 21:10

Pioneer PL15D II refurbish

Post by tetonguy » 18 Jan 2020 17:35

Hi all,
I am new to this forum but not new to Stereo repair/refurbish. Engineering background. I purchased a PL15D II and am trying to get it up to form.
Things I have done.
1. All the obvious cleaning and checking.
2. Regreased the spindle housing, ball bearing is in place, spindle has a little smooth bounce to it when platter is placed on it.
3. Motor was grease frozen. Opened it up cleaned the armature and bearings. It now runs quiet and smooth.
4. Motor mount plate had 3 chigago shoulder type screws holding it on. Each had a conical rubber dampner for isolation purposes. Cleaned and remounted same.
5. Speed change lever works fine. Belt is new.
6.Installed new headshell and Cartridge/stylus.
7. Checked all electrical connections.
Now here's where it gets weird.
It initially played one song on one record just fine. The platter had a hard time spinning after that. If I manually push it a bit it spins but there are two issues now. The speed is too slow and there is a vibrating rumble that extends to the tonearm so much that it actually shakes when the platter spins. Also the anti-skate is now way off and at any setting other than zero will pull the tonearm off the platter after a few seconds of spinning.
I did not mess with any portion of the anti-skate function other than to see that when the control is turned the corresponding lever and spring appear to be operating properly.

Not frustrated at this point just confused. I am obviously missing something about how the gear/mechanics operate here.
ALso I noted that the motor mounting plate is about 1/8 inch off the platter when the 3 screws are seated. Not sure it was always like this and could very well be the source of the vibration but I have tried all 3 screws in each nut position and they all appears to be exactly the same?? puzzling at best. I would think the motor needs to be snug to the metal deck which houses everything else and not hanging below as the pressure from the belt pulling on it would angle the motor assembly and perhaps cause the vibration I now see as well as the incorrect speed.

I would appreciate any insights as to this. I am persistent and logical and admire those who are skilled enough to help me move forward.

Thanks in advance,
Peter

tetonguy
junior member
junior member
United States of America
Posts: 17
Joined: 11 Jan 2020 21:10

Re: Pioneer PL15D II refurbish

Post by tetonguy » 18 Jan 2020 20:10

Hey all, I fixed it!!

Seems that the older Pioneer belt motors are a bit fussy. There is an upper and lower bracket that holds the armature in place, each end sits in a bearing. When I disassembled this part I failed to put it back together properly. Just the tightening of the screws which hold the bracket create enough movement to cause either some sticking or wobbling in the armature rotation. My fix was to loosely tighten them and then turn the power on and carefully position the spinning armature until it was silky smooth and quiet.

SAFETY NOTE: I am a professional degreed electrical engineer so this procedure IS NOT recommended for the DIY'r. You could easily blow the motor or give yourself a 120v shock.
I am now the proud owner of a Pioneer SL15D ii and a PL10 both working fine. I also have a older Technics and a new Pro-Ject as well.

Somehow, for me, old vinyl sounds better when I have had my hands involved in how it's presented to me....."Sweet Baby James" never sounded better!!

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