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PL-7 Turntable Odd Speed Issue

A

ampman

AK Subscriber
Subscriber
Hello everyone,
Hope your equipment is working well.
I am experiencing an odd issue on a Pioneer PL-7 I have. I'm hoping for some help in diagnosing the issue and fixing it. I believe this is a 70's or early 80's model of the PL-7
Recently it started to have a difference in speed on a recurring basis. The issue is the records seems to 'drag' every so often, maybe every revolution (at 33-1/3). I thought maybe the TT needed recapped so I did replace the caps. No change. This sound is slight an my wife did not really hear it but it's there.
It kina sounds like I'm touching the edge of the record -- you know that slight difference in speed changes the sound. It then returns to the correct speed, only to repeat soon.
The record is flat and level on the platter and the PLL light is on. The power supply voltage measured within tolerances as did the voltage at the motor (as far as I can tell).
Dos this sound like a motor issue? Is it possible to oil the bearing? I did not see any reference to oiling the motor in the service manual.
 
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I'm not very familiar with the PL-7, but it does have potentiometers for the two speeds. Have you tried cleaning and adjusting them? Here's an older AK thread that may help until someone more knowledgeable than I steps in.
 
Thanks, LF240. Appreciate the help.
Yes, while in there did clean and lube the pots and switches(thanks to prior discussions on AudioKarma).
The voltages appear good and solid after replacing the caps. This issue is like one is touching the record and letting go, only to repeat the touch. Seems to be consistent -- every rotation maybe.
 
revoc-b77 - Thanks for the reply.
To be honest I did not see any damage to the motor unit/PCB or feel any roughness spinning the motor. Holding my finger on the spindle while the motor is turning does not show any perceivable issues. Pretty smooth, really. Maybe I do not know what to look for yet have been around bearing and motors most of my life.
What should one be looking for?
One note, when starting the record, I clean it with the Discwasher system. A couple drops of cleaning fluid on the brush and then apply the brush to the record. If I apply any pressure the record stops on all three sections (wet, dry & buff). This happened before the re-cap and is better, maybe, but still happens. Is this normal?
 
Morning. I know the PL-X series of turntables quite well. The speed issue you describe is common and a consequence of oxidation in the speed switch. Send an email to beej1123j@aol.com with PL-7 in the subject line and I'll send you my guide on how to disassemble and reassemble the untitalong with some maintenance tips that will include how to resolve the speed issue.
 
revox-b77 said:
How's the spindle bearing and thrust plate?
Click to expand...

Hi,
Thanks for the reply. The spindle rotates smoothly and without any feeling of roughness/ flat /dead spots. I do not see any excessive play in the motor assembly but may not be checking it properly.

How does one check the items you mention? The service manual does not list anything, as far as I see.

Thanks.
 
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