PIONEER PL-61 motor issue

Post Reply
paronaram
Posts: 8
Joined: Thu Feb 25, 2021 6:08 am

PIONEER PL-61 motor issue

Post by paronaram »

Hello Everybody,

I have a PIONEER PL-61and it developed with weird motor issue, motor will not start on it's own. (not always, this happens on every 3-4 restart)
So I removed brand new belt and platter, and motor still not starting sometimes.
Very rarely, I can see that pulley, will spin one turn in opposite direction, and stops, and than I turn pulley a little it will start spinning.

Motor was lubricated

Can it be a power supply issue?

Thank you!
Attachments
20210705_120437.jpg
20210705_120437.jpg (146.83 KiB) Viewed 77 times
20210705_120455.jpg
20210705_120455.jpg (213.85 KiB) Viewed 77 times
Hugo
Posts: 146
Joined: Sun Feb 28, 2021 10:20 am

Re: PIONEER PL-61 motor issue

Post by Hugo »

Please provide schematics.
paronaram
Posts: 8
Joined: Thu Feb 25, 2021 6:08 am

Re: PIONEER PL-61 motor issue

Post by paronaram »

Thank you for your reply!, sorry for delay, here are some schematics.
I checked all electrolytic caps, and almost 50% had DC leakage, so I replace them all
Problem is still there.
All voltages that I have listed (TPs) on this diagram are right on the money.
Also when I push the power button, and let's say this is the time when motor does not start spinning, even if I restart the power, it will not start the motor. I will need to move pulley from that position (maybe 10DEG) so it will starts spinning, and it will work, for maybe work for 4-5 restarts, and that it will stop again. Something with Hall motor?

Thank you!
Attachments
20210711_012954.jpg
20210711_012954.jpg (167.19 KiB) Viewed 52 times
20210705_153123.jpg
20210705_153123.jpg (167.96 KiB) Viewed 52 times
20210705_153302.jpg
20210705_153302.jpg (199.06 KiB) Viewed 52 times
Hugo
Posts: 146
Joined: Sun Feb 28, 2021 10:20 am

Re: PIONEER PL-61 motor issue

Post by Hugo »

That looks really complicated. It would be helpful to add the rest of the operation description (I guess that is page six).
Ahead of that, I do think the motor it self could be at fault. What I am thinking of is that it can not start from one particular position or when perhaps relying on one coil. What you could do is to put a mark with a sharpie on the rotor opposite to an easy to recognise reference point like a screw in the chassis for instance (or draw a mark on the chassis). You need to do this when the motor fails to start and you need to get access to the rotor without allowing it to move. This could be difficult because it is belt drive. Next time when it fails again, check if the motor stops at the same position. If it fails each time at the same position it will move the motor way up on the list of suspected components. If the motor position is random when it fails, it is less likely to be the motor.
paronaram
Posts: 8
Joined: Thu Feb 25, 2021 6:08 am

Re: PIONEER PL-61 motor issue

Post by paronaram »

Sorry, there is limit to add attachments, I was not able to add more pages.
After I took motor a part, (I did not touch anything inside) just took the screws out, looked inside, did not see anything wrong with it, took a picture, put it back together, now motor does not start from many more positions. There is probably only one spot that I noticed, from where motor starts with no issues
Attachments
20210711_020154.jpg
20210711_020154.jpg (240.89 KiB) Viewed 41 times
20210711_013026.jpg
20210711_013026.jpg (157.99 KiB) Viewed 41 times
20210711_013006.jpg
20210711_013006.jpg (154.68 KiB) Viewed 41 times
Hugo
Posts: 146
Joined: Sun Feb 28, 2021 10:20 am

Re: PIONEER PL-61 motor issue

Post by Hugo »

Thanks for posting all the documentation. Based on the theory of operation and all the events you describe (notably the motor turning backwards in certain circumstances) what I would look first at are the hall generators in the motor. These devices do as described in the manual, give a voltage output based on the magnetic flux. If my understanding of the schematic is correct "point" (that is the encircled number on the main board, NOT the motor board) 3 and 5 are the out puts of the hall sensors. You should be able to get a reading of that with a DVM that modulates as you turn the motor by hand.
This should give an indication it they work or not. You should try this with the turn table in idle, i.e not asking for rotation. If that does not do anything try with the motor on but hold the shaft and turn it slowly to observe the hall outputs, even if it provides torque. (Try to do this as fast as you can to minimise the time you obstruct the motor).
Sorry I can not give you more, I hope it will bring you further.

Also, start looking for a motor on e.bay.

PS, the hall sensors go straight in that one IC that is probably obsolete. Be extra careful not to short circuit anything measuring the hall sensors. If you blow up that IC, it could be a death sentence for your Turntable.
Post Reply