Basic service of a Pioneer PL 12D

[kbhuvi]

Hello friends
Just got a entry level turntable Pioneer PL 12D which was not in service when I picked it up. I decided to do the minimum required service to get it running and up. This is how it looked initially. The dust cover is cracked but still functional and serving the intended purpose.



I had technics SL 1600 direct drive turntable earlier and on opening the hood of the pioneer i got a very rude shock. I was so used to the PCB in the technics that it thought that somebody had removed some parts from the turntable. It had a box type plinth with a vinyl sheet pasting over it giving it the look of a cheap wood. The box plinth was empty devoid of any complex electronics.



Got down to the task of giving it TLC. Started with the top plate by giving it a wipe with a damp cotton napkin. Next cleaned the tonearm with a wet earbud. I took care that the earbud was not dripping so as to avoid any unwanted fluid in sensitive places.

Then came oiling the motor. It is very simple procedure. Two drops of oil in the earmarked place. It can be seen in the photo as a red triangular arrow.



In the above photo you can see the motor and the pulley. Since it is an AC motor, the RPM is controlled by the frequency of the power supply. Turntables with such motors had 50hz and 60hz pulley for controlling RPM of the platter. You can also see the 33 to 45 speed change guide.

Then the centre spindle was unmounted by removing a screw from the top. The spindle assembly can only be removed from the inside for which you have to open the top plate. The top plate is held in place by two screws which can be slided towards the spindle.






The spindle is held in bearing well by a grub screw on the side. The spindle can only be removed if you remove the grub screw. A little force is required as pulling the spindle out creates a mild vacuum which creates a mild resistance.

The spindle and the well were cleaned using cotton only. Take care while cleaning as there is a small bearing inside the well which needs to be removed carefully otherwise you might lose it. It was fortunate that i had opened the spindle as it did not have any oil in it.

A small squirt of Honda Activa synthetic gear oil was used in the bearing well. After the oil was put in the brass well, the spindle would not sit in it. I temporarily installed the spindle again without the grub screw and mounted the platter. I kept some cloth underneath the spindle for the excess oil that would spill out. The indication that the spindle is sitting in the well perfectly is that on tightening the grub screw, it would not restrict the rotation of the spindle.




The top plate is balanced on four springs. To damp the springyness, it is recommended that you use foam inserts and some rubber washers under the springs. I made the rubber washers using a discarded bicycle tube. The top was levelled using different number of washers under the four springs.


Then polished the rubber mat, platter, dustcover and cleaned the cables. Some before and after pictures.

 

[Hiten]

For this type of turntables no electronics are required. AC motor are known for torque and speed stability as they run on AC line frequency. Some Belt drive Thorens specific motors do have specific value capacitor for phase delay (for two pole windings) so vibration are reduced. But these are minor improvements. As for Cheap Box plinth. These are spring suspended turntables (Just like Garrard Changers) No heavy plinth is required. If you wish you can put the player on one OR one and half inch thick wood base (MDF ?). However if the rubber grommets on which motor is kept are hard it will affect sound quality the most. Do check those. All the best.

 

[kbhuvi]

For this type of turntables no electronics are required. AC motor are known for torque and speed stability as they run on AC line frequency. Some Belt drive Thorens specific motors do have specific value capacitor for phase delay (for two pole windings) so vibration are reduced. But these are minor improvements. As for Cheap Box plinth. These are spring suspended turntables (Just like Garrard Changers) No heavy plinth is required. If you wish you can put the player on one OR one and half inch thick wood base (MDF ?). However if the rubber grommets on which motor is kept are hard it will affect sound quality the most. Do check those. All the best.

Thanks for pointing out. Checked the rubber grommets. They are in excellent condition - soft and supple.

I did not get the use of a small aluminium ring which can be seen the last photo. I have kept it on the cork mat.

The turntable is now able to maintain the speed inspite of the old belt installed on it. Will install the new thaker belt when it arrives. The sound quality is better than i had expected out of this humble machine.

In the wanted section i had posted about the tonearm play in the vertical bearings. The bearing has two screws one inside the other. I tightened the inner one with a flat head jeweller screwdriver and the play is now negligible. The photo of the screw is below.

 

[reubensm]

Yeah, the PL12D is a belt deive turntable and it was one of Pioneer's well regarded and most popular decks. One of the key advantages of this deck was its simplistic design and low price. It retailed in those times for about $50-$60 and was sold in huge numbers as a result. It was the start for many hi-fi enthusiasts on a budget. The design philosophy of Technics DD turntables is obviously different. They used DC motors with electronics for the servo controlled speed controller or quartz controlled speed controller, depending on the model. Pioneer used AC motors for their PL series turntables (as Hiten rightly pointed out) and hence additional electronics was not required. The change in speed was achieved by a small lever lifting or dropping the belt over the thinner or thicker ends of the motor pulley (yes, it was that simple). For the Pioneer motor, all that was required was a small capacitor which was used as the spark suppressor for the motor switch. In a way, not having electronics is a blessing in disguise. Imagine if a Technics DD went kaput, you'd have to break your back to fix the circuitry, that too, if only you are able to get spare parts, especially IC replacements. This is so simple, just like the Garrards, so easy to deal with. (on a personal note, i have just let go of my personal Technics SP10 mk2 and also stayed away from EMTs, etc as this philosophy of a simple AC motor driving my deck, does not give me sleepless nights or put my bank balance at risk )

Yes, to keep costs down, Pioneer used compressed wood with vinyl sheets pasted over them. But not sure if a plinth upgrade will better the performance to a great extent.

 

[Hiten]

Please Please Please do not remove the bearing screw. These have half mm ball bearings. (I have been through all this) And can easily be lost forever. The aluminum ring I suppose is just for aesthetic purpose. Trust me Belt will improve things drastically. Don't forget to enjoy the mods and tweaks later on
Regards.

 

[kbhuvi]

Yeah, the PL12D is a belt deive turntable and it was one of Pioneer's well regarded and most popular decks. One of the key advantages of this deck was its simplistic design and low price. It retailed in those times for about $50-$60 and was sold in huge numbers as a result. It was the start for many hi-fi enthusiasts on a budget. The design philosophy of Technics DD turntables is obviously different. They used DC motors with electronics for the servo controlled speed controller or quarts controlled speed controller, depending on the model. Pioneer used AC motors for their PL series turntables (as Hiten rightly pointed out) and hence additional electronics was not required. The change in speed was achieved by a small lever lifting or dropping the belt over the thinner or thicker ends of the motor pulley (yes, it was that simple). For the Pioneer motor, all that was required was a small capacitor which was used as the spark suppressor for the motor switch. In a way, not having electronics is a blessing in disguise. Imagine if a Technics DD went kaput, you'd have to break your back to fix the circuitry, that too, if only you are able to get spare parts, especially IC replacements. This is so simple, just like the Garrards, so easy to deal with. (on a personal note, i have just let go of my personal Technics SP10 mk2 and also stayed away from EMTs, etc as this philosophy of a simple AC motor driving my deck, does not give me sleepless nights or put my bank balance at risk )

Yes, to keep costs down, Pioneer used compressed wood with vinyl sheets pasted over them. But not sure if a plinth upgrade will better the performance to a great extent.

Noted sir.
It also has a low weight platter. Cant expect much such a humble machine. A good tonearm would surely make it sound better.

Looking forward to experiment with plinths and tonearms.

 

[kbhuvi]

Please Please Please do not remove the bearing screw. These have half mm ball bearings. (I have been through all this) And can easily be lost forever. The aluminum ring I suppose is just for aesthetic purpose. Trust me Belt will improve things drastically. Don't forget to enjoy the mods and tweaks later on
Regards.

Already done that. I was aware of the ball bearing so approached it as gently and carefully as cutting nails of a toddler.

 

[Hiten]

You are doing it like pro kbhuvi. Enjoy the journey.
Contrary to popular belief of sponges in the suspension springs are not for vertical damping. They are I guess damp horizontal movement. I learned this from extensively reading about working of Linn LP 12 turntable. Which I consider a classic masterpiece belt drive turntable.
Regards.

 

[reubensm]

Forgot to mention, one common headache with old Technics DD turntables is that over time, the transformers tended to hum, adding rumble. With AC motors, this possibility is eliminated

Does the "light weight" platter mate properly with the spindle assembly? Turntable wobble was a common issue with these turntables. Light weight platters were common on this range of belt drives, from most manufacturers.

 

[Hiten]

Already done that.

 

[G401fan]

Remove the sponge/foam from the spring assembly. It impedes the motion of the springs, and removing it will give you better damping. This has been a general consensus with the Thorens models which first started this practice.

 

[kbhuvi]

Forgot to mention, one common headache with old Technics DD turntables is that over time, the transformers tended to hum, adding rumble. With AC motors, this possibility is eliminated

Does the "light weight" platter mate properly with the spindle assembly? Turntable wobble was a common issue with these turntables. Light weight platters were common on this range of belt drives, from most manufacturers.

The platter fits perfectly. No wobble noticed at both speeds. The spindle has no visible indications of being worn out. Will keep it mind for future issues.

 

[kbhuvi]

Remove the sponge/foam from the spring assembly. It impedes the motion of the springs, and removing it will give you better damping. This has been a general consensus with the Thorens models which first started this practice.

Most of the posts i read regarding the Pioneer 12D indicated that it had a very thin top plate compared to the Thorens, resulting in the springiness which needed to be damped to reduce its springiness. I also noticed the softness and hence the foam.

The turntable is placed on a solid wood rack weighing around 70kg so vibration should not be an issue. I will remove the foam and use it for a couple of days to test it out. Will update my findings in due time.

 

[kbhuvi]

Ii would like some ideas on economical means to add weight to the platter without disturbing its weight distribution geometry or motor dynamics.

 

[sachu888]

Your TT has very low torque, so platter weighs less like most of the belt drive TT. I don't think you need to make it heavy.

Regards
Sachin

 

[jls001]

If you like what you're hearing now, better to enjoy it "as is". Modifications are usually time, money and energy drains.

 

[kuruvilajacob]

I just saw this post. All that needs to be done before using a vintage turntable like Pioneer PL 12 D has been done. I also gets all these procedures done with every Turntable that comes to me. It's like buying an old car. If you take an old car after you buy it to an experienced mechanic, he will immediately change engine oil, break fluid, etc . So any old turntable to be trouble free needs these overhauling IMO. Sometimes, the bearing in the tonearm will need to be taken out and cleaned and relubed for smooth arm movements. I will always depend on professionals to do it .