Restoring a Pioneer PL-630 Turntable

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Hi Rich,
I am new to this whole scene of hobby repair work on audio equipment but I am very intrigued by rebuilding a table I was gifted. I turned the table on for a few months and it was running beautifully. Then the speed issue started. In the year that the table sat with me researching how to repair it, the button for the tone arm lift began to stick. When i turn the table on the mechanism for lifing the tone arm will move if I happen to hit the button and make contact but the tone arm will not setltle onto the actual record as it did before. I have read over your thread, and began trying to diagnose the problem. I have the table apart on my work bench and was wondering if their was any insight you could give me into what those problems may be. Also, i detached the circuit board from the switch for the button, but cant figure out how to access the two small columns to observe the mechanism (maybe springs) that would allow the tonearm button to rise.

Thanks,
John
 
Hi Rich,
I am new to this whole scene of hobby repair work on audio equipment but I am very intrigued by rebuilding a table I was gifted. I turned the table on for a few months and it was running beautifully. Then the speed issue started. In the year that the table sat with me researching how to repair it, the button for the tone arm lift began to stick. When i turn the table on the mechanism for lifing the tone arm will move if I happen to hit the button and make contact but the tone arm will not setltle onto the actual record as it did before. I have read over your thread, and began trying to diagnose the problem. I have the table apart on my work bench and was wondering if their was any insight you could give me into what those problems may be. Also, i detached the circuit board from the switch for the button, but cant figure out how to access the two small columns to observe the mechanism (maybe springs) that would allow the tonearm button to rise.

Thanks,
John
Also, I have a pl-610 not 630
 
Hi Rich,
I am new to this whole scene of hobby repair work on audio equipment but I am very intrigued by rebuilding a table I was gifted. I turned the table on for a few months and it was running beautifully. Then the speed issue started. In the year that the table sat with me researching how to repair it, the button for the tone arm lift began to stick. When i turn the table on the mechanism for lifing the tone arm will move if I happen to hit the button and make contact but the tone arm will not setltle onto the actual record as it did before. I have read over your thread, and began trying to diagnose the problem. I have the table apart on my work bench and was wondering if their was any insight you could give me into what those problems may be. Also, i detached the circuit board from the switch for the button, but cant figure out how to access the two small columns to observe the mechanism (maybe springs) that would allow the tonearm button to rise.

Thanks,
John
First, do not use DeOxit, or any other contact cleaner around that switch. It is a snap-dome switch and will be damaged by contact cleaners.

The actual switch (snap dome) is mounted to a small circuit board, that is held in a small case. Two screws hold the case to the control panel. The button actuator is retained by 2 c-clips. There may only be 1 spring, on one of the two guide pins. The spring force is quite light, and is there to keep the actuator at the top of its travel, if the button does not push it all the way up there. Most of the spring-back of the mechanism is provided by the snap dome of the switch.

If the actuator is not binding anywhere, then it is likely that the snap dome switch has collapsed. If so, It will need to be replaced. Make sure the button opening in the control panel is clean, and free of damage around its inner circumference. Make sure that the guide pins are clean and not binding in their housings. Make sure the spring(s) is present. Barring any mechanical binding, the only other option is the collapsed snap dome. I do not have one of these open right now to see if a modern replacement is available for the switch itself. I will be into a PL-630 in a week or so, I can look then. Just know that you might need a parts unit for a faithful replacement. Some folks here have various PL-630/610 parts laying around. Just start your own thread, in the proper forum area, and ask if anyone has the part you need. This a good group of folks.

Good luck,
Rich P
 
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User Control Work

Remove the speed select and quartz lock switches, remove the phenolic cover plates, and manually polish the contacts with a non-abrasive pencil eraser (DeOxit is not good enough for these switches (silver contacts that turn badly black), then corrode right back up), then put some Deoxit in for lube and anti-corrosion properties, and reassemble (Better be real careful with this operation, as these switches are VERY delicate. Also, you do not need to remove the springs and front pieces to open up the switches.
Rich P

Firstly, thank you, thank you, thank you Rich P for all the info and pictures! I am working on a friend’s PL-630 and have found this thread to be invaluable.

It had speed problems including running in reverse and runaway forward speeds. At first I tried the “pushing the 33/45 and Quartz Lock buttons hundreds of times” method, which helped some, but the problems returned very soon. So I desoldered those switches and took them apart for the proper cleaning that Rich P describes earlier in this thread.

I took some pictures in case others who are considering doing this can see what they are getting into. As Rich says, careful handling is required, as there are some delicate little metal parts that can easily be bent (or tumble to the floor, never to be seen again) and then switch no-more-worky. Here are some details to add to Rich's info.

This is how I did it:
- With a small screwdriver that has a long taper (so that a flat area is on both the leverage point and retaining tab you are prying up, otherwise round shaft can slip off leverage point) and using the stand-off/larger tab as a leverage point, carefully pry up and out on the small retaining tabs that hold the phenolic plate to the body of the switch. The larger tabs will be slightly bent inward and can be bent back out (I used needle-nose pliers), just enough to be out of the way for the phenolic to lift straight up.
- Gently remove sliding contact pieces off the stationary contacts (or out of their cavities, if any remain in the switch body) and put them somewhere safe.
- If you tried putting Deoxit or anything else in the switch, clean it off (I used some Radio Shack no-residue contact cleaner spray - very effective on oils etc.)
- Carefully scrub oxidation off with pencil eraser. The eraser will get pretty chewed up so be careful that the metal tube holding eraser doesn't scrape the contacts - use another eraser if it is getting close. Keep going until ALL the oxidation is gone from all sides of those contacts. Shiny. Brush eraser residue from contacts (use a non-metallic brush) and plate.
- Position sliding contacts on stationary contacts so they are in position to drop right into their respective cavities. As Rich says, add a little Deoxit for future corrosion protection and lube.
- Lower phenolic plate back into switch body - if it does not slide easily back into place, do not force it, the sliding contacts can get bent and ruined.
- I used a pair of stiff needle-nose pliers to bend the retaining tabs back into place (with plier jaw on the tab and the other diagonally across the body, slightly offset to be pushing either more "down" on the tab or more "in" on the tab) , bending little by little and checking along the way that the switch could be pushed in and out freely and without restriction.
001_IMG_4755.JPG 002_IMG_4743.JPG 003_IMG_4744.JPG 004_IMG_4746.JPG 005_IMG_4747.JPG 006_IMG_4748.JPG 007_IMG_4751.JPG
The oxidation can clearly be seen, as can the lack of oxidation after using the eraser on the contacts.
The speed problems seem to be gone, at least so far.

Now there’s the problem of the speed meter, which is receiving a voltage of appx. +4v, causing it to peg hard left (I think it was left. The meter has been out of the control circuit board for several weeks now.)
Not sure if I should start a separate thread for that or continue here ...?
 
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Suspension Boot Augmentation

Here we begin actual restoration procedures...

After 30 years rubber tends to dry-rot, caused by ozone and other natural processes. The rubber boots, that are part of the suspension, do take a hit on most of these units. Here we will repair and augment them.

Remove the 4 suspension assys (located where the feet were, in the corners of the base-plate), as follows:
  1. Remove the single screw that secures the suspension retainer to the base-plate

  2. Rotate the suspension retainer a few degrees, freeing the suspension assy out the bottom of the base-plate.
Note: Mark the location of each suspension assembly, on the spring of the assy and on the base-plate where it was located. They will have to be returned to where they came from for proper effect. This is important, because the 4 springs are not the same tension, minimizing the potential for resonance in the suspension.



Rich P

hi rich, so i finally got everything to put the tt back together.... but i seem to have hit a problem... in my zeal to clean everything i cleaned the markings off of the springs....
anyway, i noticed that there seem to be two different types of springs. one wider coil and one tighter coil. do you know what positions they should be in?
thanks for any help.

chif
 
hi rich, so i finally got everything to put the tt back together.... but i seem to have hit a problem... in my zeal to clean everything i cleaned the markings off of the springs....
anyway, i noticed that there seem to be two different types of springs. one wider coil and one tighter coil. do you know what positions they should be in?
thanks for any help.

chif
The 2 with the fewer turns per inch are made out of a slightly bigger gauge, and so are slightly stiffer. The stiffer springs are in the front left (closest to platter motor) and right rear (under tonearm mechanism), as viewed from the front of the unit.

Enjoy,
Rich P
 
hi rich, thank you again for all your help. my 630 is all buttoned up and running great. though i have another question for you. ever since i got the tt ive noticed that the lateral level of the tonearm gimbal to be a bit off. it causes the cartridge to have a slight slant downwards towards the center. is there any way to adjust that level or pitch?
 
hi rich, thank you again for all your help. my 630 is all buttoned up and running great. though i have another question for you. ever since i got the tt ive noticed that the lateral level of the tonearm gimbal to be a bit off. it causes the cartridge to have a slight slant downwards towards the center. is there any way to adjust that level or pitch?
The gimbal bearings are not retained if you remove the bearing cone. Sometimes folks remove the bearing cones and lose a bearing. That will make a cant. Other than that, there may have been an impact to that side of the gimbal and there is damage. Parts units are required for either problem.

Enjoy,
Rich P
 
ok so:
1. i should source a donor gimbal i suppose?
2. how would i disassemble the gimbal? would you know what tools are needed?
 
ok so:
1. i should source a donor gimbal i suppose?
2. how would i disassemble the gimbal? would you know what tools are needed?
First, this is not a DIY operation. It requires a delicate feel that comes from experience or factory equipment. It may even be that the left side bearing cone has backed out slightly, due to a loose adjusting collar. In any case, too tight and you won't track for beans. Too loose and you will pick up a rattle during play.

Second, I would not spend the money on a new tonearm without a solid diagnosis. Sometimes it is only a bit of play in the headshell mount, allowing the headshell to rotate back or forth a bit.

Enjoy,
Rich P
 
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Thanks again rich. Actually the playing does not seem to be affected at all. The canting is very very slight. Though if I try to jiggle the gimbal there is an ever so slight lateral movement/looseness. Again the playing seems fine and the arm tracks well. I guess I am just nitpicking the tt visually.
 
Thanks again rich. Actually the playing does not seem to be affected at all. The canting is very very slight. Though if I try to jiggle the gimbal there is an ever so slight lateral movement/looseness. Again the playing seems fine and the arm tracks well. I guess I am just nitpicking the tt visually.
For your information and entertainment, read this whole thread through (it is short): https://audiokarma.org/forums/index.php?threads/looking-for-pl-630-610-parts.690740/

Again, the bearing balls are not retained. If the bearing cone is removed, or loosened too much and it comes out, one or more bearing balls usually drop out with it, and jump to hidden locations. Even if you fine it (them), getting it(them) back into the bearing will be a mother bear. ONe may already be missing, by your description. By the way, the balls are the same size as those under the head plate of CT-F9XX cassette decks.

Enjoy,
Rich P
 
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so perhaps i can get such a cassette deck and use its bearing to repair my gimbal? but you did say getting the bearing back in is a major pita....
 
so perhaps i can get such a cassette deck and use its bearing to repair my gimbal? but you did say getting the bearing back in is a major pita....
You do not have a definitive diagnosis yet. Diagnose... then repair. You may have an optical illusion. That would be hard to fix, indeed. And, yes, getting an errant bearing ball in there will be a serious pain.Just trying to see if one were missing would be a serious pain.Tonearm bearing issues are not recommended as DIY operations, as previously stated. The PL-630 I have on the bench right now "appears" to cant toward the center slightly...optical illusion.

Enjoy,
Rich P
 
Hi Rich P. Thank you for this great and thorough restoration guide! I successfully fixed my cracked tonearm pick-up plate. I manufactured a little metal band and held it in place with the set screw just like you suggested. Now everything is back together but my main problem still exists:
When I power on the table it starts spinning immediately, no matter if it is in automatic or manual mode. When I hit the Start/Stop button the tonearm swings back endlessly. The platter never stops spinning. I looked underneath the tonearm board where the motor is and it appears it is spinning in the wrong direction. My guess is that the table "thinks" it is already running and hitting the start button is a stop function.
Do you have any suggestions how to trouble shoot this problem? I checked the 2 micro switches at the tonearm and they work.
Thanks for any help. Best, Stefan
IMG_75121.jpg
 
The pickup plate must be properly positioned, or you will have all kinds of issues. When the tonearm is in its rest, the set screw should be facing straight back. To fine tune, set the drop point adjustment screw to mid-point. Then adjust the rotational position to get the drop point very near to correct. Then the drop point adjustment screw can be tweaked for fine tuning. Make sure that the pick-up plate is vertically adjusted on its shaft, so that it does not rub on the optical pickups, or you will have skipping during play.

If the platter still does not stop when the tonearm is in its rest, you will have a bad photo transistor, or led, or control chip. You are entering an area where a knowledgeable tech will be needed.

Good luck,
Rich P
 
The pickup plate must be properly positioned, or you will have all kinds of issues. When the tonearm is in its rest, the set screw should be facing straight back. To fine tune, set the drop point adjustment screw to mid-point. Then adjust the rotational position to get the drop point very near to correct. Then the drop point adjustment screw can be tweaked for fine tuning. Make sure that the pick-up plate is vertically adjusted on its shaft, so that it does not rub on the optical pickups, or you will have skipping during play.

If the platter still does not stop when the tonearm is in its rest, you will have a bad photo transistor, or led, or control chip. You are entering an area where a knowledgeable tech will be needed.

Good luck,
Rich P
Thanks for the answer. I did position the pick up plate accordingly but it did not make any difference. My guess is that the photo transistor, which is called the Rest Switch in the service manual, might be damaged or something in the corresponding circuit. I am sure that photo transistor would not even be available anymore.
 
Thanks for the answer. I did position the pick up plate accordingly but it did not make any difference. My guess is that the photo transistor, which is called the Rest Switch in the service manual, might be damaged or something in the corresponding circuit. I am sure that photo transistor would not even be available anymore.
That is a good likely culprit. I think I have participated in a thread where I remotely assisted a DIY'r to repair his PL-630 that had the same problem. I will go look for it. If I find it, I will come back and post a link to it.

Enjoy,
Rich P
 
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Hi, Great thread you have here Rich!
I was just wondering about what you wrote in user control work part 6: Remove the speed select and quartz lock switches, remove the phenolic cover plates, and manually polish the contacts with a non-abrasive pencil eraser (DeOxit is not good enough for these switches (silver contacts that turn badly black), then corrode right back up), then put some Deoxit in for lube and anti-corrosion properties, and reassemble (Better be real careful with this operation, as these switches are VERY delicate. Also, you do not need to remove the springs and front pieces to open up the switches.

My issue here is that when I use the pitch meter(non active quartz) everything is ok when i turn pitch adjust screw, the needle meter moves nicely back and forth. But, when I activate the quartz, the meter needle goes a little to the right of perfect pitch, if I slightly(very carefully) touch the button the needle will go to perfect pitch again. I think It must be a bad contact here. I must mention it only affects the needle in the meter and not the actual speed of the platter. Any suggestions on how to solve this Rich? Thanks in advance.
 
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