Restoring a Pioneer PL-630 Turntable

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pustelniakr

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Stylus Drop Point Adjustment

You will need an old record, you don't care if it gets scratched, for this operation.

With the platter and mat installed, as well as the headshell, cartridge, and counterweight, adjust the tracking force and anti-skate to reasonable settings (you will get more accurate after the unit is completely reassembled).
  1. Put an LP on the platter.

  2. Press the lift button.

  3. When the lift is complete, verify that the lifter lifts the stylus high enough to clear the LP, but only enough to clear the LP if it had a bit of warp. If it is not set properly, loosen the lifter setscrew (seen earlier) and move the lifter arm up or down, for a reasonable lift. Note: If too high, the lifter ramp curve will be incorrectly selected, and the stylus will drop too hard onto the LP.

  4. Slowly move the tonearm across its full range of motion and make sure that the stylus will clear the LP all the way across, adjust the lifter height as necessary.

  5. Leave the arm lifted, and but return it to its rest.

  6. Remove the stylus drop adjustment cap and don't lose it. (see pic 1)

  7. Look down in the hole covered by the cap, and rotate the tonearm to near where it will need to drop the stylus. You will see a screw head come into view. That is the stylus drop point adjustment. With a jeweler's screwdriver (common), rotate the screw through its range of motion, then turn it to approximately mid-range (gentle here, remember the pickup plate is only just secured to the tonearm shaft, and this screw is on that plate).

  8. Return the tonearm to its rest, but leave it lifted.

  9. Make sure the 'Auto' control is active, and 12" disk is selected, then press the start button. The tonearm will move to where it is set to drop the stylus, but stay up.

  10. By repeated 'start' pressings and adjustments, set the drop point to a reasonable place, by loosening the optical pickup plate setscrew and changing its relative rotation to the tonearm until the the drop point is reasonable. Fine tuning will be next.

  11. Before leaving the pickup plate adjustment, shine a light in from the back and verify that the pickup plate clears the top and bottom edge of the optical sensor, being positioned, up or down on the shaft, approximately midway between them. If you don't, you will drag during play and your records will skip. Once satisfied, firm up the setscrew, just enough that the pickup plate does not rotate when the actual drop point screw is rotated.

  12. Fine tune the stylus drop point, via adjustment screw in the hole. Turn the screw one way and the drop point moves in. Turn it the other way, and the drop point moves out. Once you think you have it right, return the tonearm to its rest, lower it, and press start. The stylus drop point is properly adjusted when the stylus puts down just at the bottom of the hill you see on the edge of the LP, when viewed from the side. If too far in, it will drop inside the start of the 1st song. If set too far out, the stylus will slide down the hill and skip across the 1st couple of grooves of the 1st song.

  13. Lift the tonearm and drop it at the end of the last song (a couple of times), and watch to make sure that the table senses the end of the LP and properly returns the arm to its rest. Also verify that proper functioning in repeat mode (where the arm returns to the start of the LP).
36 - Adjustment Cap.jpg

Enjoy,
Rich P
 

pustelniakr

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Final Adjustments

Reassemble the unit, up to putting on the feet.
  1. Install the feet, adjusting the suspension properly, by rotating the collar on each foot until an equal number of threads are seen above and below the collar. Then push the foot into its place, and hold it so it does not rotate as you insert and tighten its screw.

  2. Check the suspension setting, by putting the platter on, them pressing gently up and down on the platter, making sure that the upper and lower limits of bounce are equal (you can hear it hit the limits). The platter (and tonearm assy) should move up and down readily, and not be pinned to the bottom or the top of motion.

  3. The tonearm height (Vertical tracking angle) should be set so that the tonearm is parallel to the LP when the LP is playing.

  4. The lifter height should be set so that the stylus will clear a slightly warped LP, when lifted, across the full range of tonearm motion. If the stylus drops onto the LP too hard, you have the lifter set to lift too high.

  5. The tonearm rest height should be set so that when the tonearm is lowered onto it, it has to drop only a few mm, and the lifter drops away from the arm.
37 - Final Adjustments.jpg

Enjoy,
Rich P
 

pustelniakr

Silver Miner at Large
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Cosmetic Detailing

Hear are a few tricks of the trade for the cosmetic detailing:
  1. This thread details how to polish out the dustcover: http://www.hifihaven.org/index.php?threads/restoring-a-turntable-dustcover.4305/

  2. Do not use harsh chemicals on the plinth, platter, or front panel. Limit your chemicals to a soft toothbrush and dish soap (not dishwasher soap).

  3. The front panel lettering tends to come off "VERY" easily. It is not stamped in like other pioneer products. Do not brush it, rub on it, or even run it under water and soap. Clean it with q-tips and stay off the lettering and labels. If you do not, you will know why I am saying that, first hand.
We are now completely done. Be careful, slow, and meticulous, and you will have a super sweet machine to listen to. I recommend a nice Benz Micro MC Silver cart. It is what I use, and it pairs with this table so well that it turns LPs in almost videos, it images so well.

Additional info:
Enjoy,
Rich P
 
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pustelniakr

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Supplemental Info:

Repairing a cracked pick-up plate (very common with this model):

For the cracked plate assy, you need to band the part with a thin metal. If your setscrew is an Allen, you can drill a tiny hole above the setscrew for a #2 self-threading screw to hold the band together. If you have the newer Phillips setscrew, you can use the setscrew to hold the band together. The band should be made of very thin metal, like an old eraser mask (drafting supplies). Cut it in the proper width and length with tin-snips, and form it around tightly. The band overlaps on the setscrew face of the assy. Drill the holes in the band for a tight band and install. If done right it is better than new.

IMG_75121.jpg

Enjoy,
Rich P
 

pustelniakr

Silver Miner at Large
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Supplemental Info:

The Platter Never Stops:

____________________________ client __________________________________

...The issue with my turntable is possibly two-fold, though it may be a single issue causing the symptoms.

First: when I tap the Power button, the platter will start spinning, usually within 3-6 seconds.

Second: The auto function is dysfunctional. Once power has been applied, tapping the Start/Stop button initiates action (the tonearm raises), but it stays “engaged” and tapping the Start/Stop button (or any other button) has no effect. Power must be shut off, and when power is reapplied, then the tonearm lowers back to its proper position (and the platter starts spinning).

If I choose to listen to an album using the manual method, everything is fine until the end of the album. The tonearm does not lift up, nor return. (using the cueing button works fine)

Everything else works fine, the sound is awesome, I really enjoy this turntable. I just really would like full functionality to return.

Work I have done: De-oxit’ed the appropriate switches, and speed pot (but not the dome switches, of course!), replaced the tonearm belt (it came from Vintage Electronics), replaced all capacitors (transistors untouched at this point), repaired the usual crack in tonearm pickup plate (using .005 shim steel -- see photo at end of this), and replaced the LED indicator lamps with blue ones. I also have a spare NOS chip, a PA2005, but have not needed to use it at this point.

Last bit of explanation: I purchased this turntable with the issues listed above. Everything I accomplished has not caused any changes in the symptoms. In other words, what worked before still works now...
 

pustelniakr

Silver Miner at Large
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Supplemental Info:

Platter Never Stops (cont.):

____________________________ pustelniakr __________________________________


...I need some clarification.

You say you tap the power switch. Does this mean that the platter begins turning, with the tonearm in its rest, as soon as power is applied?

The problem, where the tonearm does not lift at the end of an LP, could be related or may indicate a separate issue.

The two main issues you mention have two significant parts in common.

The first, and least desirable cause is the PM6001 chip on the tonearm drive board. An NOS source or a parts unit would be required for replacement.

The second part in common is the pickup plate and its placement. When installed properly, the screw in the pickup plate, that secures it to the tonearm shaft, must be facing straight back when the tonearm is locked in its rest. If this is not the case, it could cause both issues you are mentioning.

If the problems are not linked by the pickup plate position, then the chip could still be the issue. There are other unavailable parts (arts unit needed) that could be involved.

...Position the pickup plate so that the setscrew faces straight back when the tonearm is locked in its rest. If that does not help, try setting the pickup plate + and - 10 degrees. Lets see what the effects are...

Enjoy,
Rich P
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ client __________________________________


Hi Rich,

Thanks for getting back to me!

Tackling your questions in order, my replies are in blue.

pustelniakr said:
You say you tap the power switch. Does this mean that the platter begins turning, with the tonearm in its rest, as soon as power is applied?
Correct. I engage the Power button, and without touching anything else, the platter begins to turn. The tonearm stays in its rest. Generally, the platter starts turning within 3-5 seconds of the power button being pushed.

pustelniakr said:
The problem, where the tonearm does not lift at the end of an LP, could be related or may indicate a separate issue.

The two main issues you mention have two significant parts in common.

The first, and least desirable cause is the PM6001 chip on the tonearm drive board. An NOS source or a parts unit would be required for replacement.
I understand.

The second part in common is the pickup plate and its placement. When installed properly, the screw in the pickup plate, that secures it to the tonearm shaft, must be facing straight back when the tonearm is locked in its rest. If this is not the case, it could cause both issues you are mentioning. First, lets see if the pickup plate positioning is the issue. I know you said you visited that, but take another shot, and see. I would hate to have you spend beaucoup bucks to get the unit to me for me to fix it by rotating the pickup plate.

Position the pickup plate so that the setscrew faces straight back when the tonearm is locked in its rest. If that does not help, try setting the pickup plate + and - 10 degrees. Lets see what the effects are...
Oh yes, I have spent a great deal of time with the pickup plate, including trying different positions. That would be a wonderfully easy fix, and in doing so, thought it would solve my issue. But, I have tried everything from dead on straight back to nominally increasing degrees + and - . (Even to 15 and 20 degrees of variation). The only change I witnessed was that as I got further and further away from dead on (in either direction, + or - , it didn't matter) was that the platter would start spinning immediately upon application of power. Once I brought it back to dead on center, then I would be back to the original symptom (platter spinning within 3-5 seconds). I was also careful to maintain the plate in the vertical center of the optical sensor.

If the problems are not linked by the pickup plate position, then the chip could still be the issue. There are other unavailable parts (parts unit needed) that could be involved.
Not a pleasant thought, but I understand.

You're right, serious considerations all. I have to admit, I'm driven on solving this problem (unresolved issues really drive me crazy!) but I also have to take a step back and consider alternatives. On one hand, I know I can get this turntable back to full functionality (with additional help and expense) and on the other, it may make equal sense to throw in the towel, sell it as is, and hold out for a serviced unit (which doesn't necessarily guarantee reliability nor longevity!).

...I guess the main issue bugging me is that I don't know what's causing the problem with this unit.

I would appreciate if you have any other thoughts in this matter.
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ pustelniakr __________________________________


I just don't have time for remote troubleshooting, but I will try one iteration (a bit more if not too much time is required), to see if we can get enough info to narrow down the issue. Follow the following instructions to the letter and report back results:

All of the following measurements are on the tonearm drive board, with the negative meter lead connected to TP4

- Measure the voltage at TP7

- Measure the voltage at TP6

- Put the tonearm in "up" position, in its rest. Measure the voltage at TP2

- Move the tonearm to a position directly over the last groove on an LP. Measure the voltage at TP2

- Move the tonearm to a position directly over the lead in groove of an LP. Measure the voltage at TP1

- Leave the tonearm in the same place. Measure the voltage at TP5

- Move the tonearm to its rest, and put it in its "down" position. Measure the voltage at TP5

- Leave the tonearm in the same place. Measure the voltage at TP1

- (If you have an oscilloscope) With the platter spinning, observe and describe the signal at TP8

Now make sure that the following connections are good:

- Tonearm board TP5 to platter drive "STOP"

- Tonearm board TP8 to platter drive TP23

- Tonearm board TP1 to Control B board TP4

Is the tonearm drive motor spinning when the unit is initially powered up?

Be careful and accurate,
Rich P
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ client __________________________________

Here's my results, checked everything twice. Hope something jumps out at you.

All of the following measurements are on the tonearm drive board, with the negative meter lead connected to TP4
OK, will do

- Measure the voltage at TP7
+26.8 vDC

- Measure the voltage at TP6
+ 7.8 vDC

- Put the tonearm in "up" position, in its rest. Measure the voltage at TP2
+.181 vDC

- Move the tonearm to a position directly over the last groove on an LP. Measure the voltage at TP2
+9.93 vDC

- Move the tonearm to a position directly over the lead in groove of an LP. Measure the voltage at TP1
+6.37 vDC

- Leave the tonearm in the same place. Measure the voltage at TP5
+.729 vDC

- Move the tonearm to its rest, and put it in its "down" position. Measure the voltage at TP5
+.729 vDC

- Leave the tonearm in the same place. Measure the voltage at TP1
+6.36 vDC

- (If you have an oscilloscope) With the platter spinning, observe and describe the signal at TP8
Sorry, don't own one!

Now make sure that the following connections are good:

- Tonearm board TP5 to platter drive "STOP"
Continuity checked good

- Tonearm board TP8 to platter drive TP23
Continuity checked good

- Tonearm board TP1 to Control B board TP4
Continuity checked good

Is the tonearm drive motor spinning when the unit is initially powered up?
No, it is not
 
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pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ pustelniakr __________________________________


Your two errors have a small incandescent lamp in common (under the tonearm). You should see it producing light whenever power is applied. Check for it, so you know where it is. I know it is producing light, because the end detector response shows it. The lamp is mounted in a frame, facing downwards. directly beneath it is a CdS sensor (end detector), which appears to be working.

Mounted at right angles to the line between the lamp and the CdS sensor is a small circuit board. On that circuit board is a small, clear, 2-leaded photo-transistor. This photo-transistor receives light from the lamp whenever the tonearm is not in its rest. Whenever the tonearm is in its rest, there is a small shield on the pickup plate that blocks the light from hitting the photo-transistor.

From your measurements, the indication is that the photo-transistor is still receiving light, even with the tonearm in its rest. Here are some possibilities:

- The pickup plate is not positioned properly

- The small light shield on the pickup plate has been broken off, or damaged (light is getting by, hitting the photo-transistor)

- The photo-transistor is bad (shorted, or low resistance across its 2 leads)

- Transistor Q3 is bad (shorted, or low resistance between emitter and collector)

- Some kind of solder splash in the area of R5 (1K), R6 (1.6K), Q2 (the CdS), or Q3

Check those items and report back. Look below for what should be seen when working right, so you can see when you have fixed it.

- TP-5 should be around 0v (not .75v), when the tonearm is in its rest

- TP-1 should be around 0.3v (not 6.4v) when the tonearm is in its rest
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ client __________________________________


It took a little bit, but I got through it. After checking out your first instruction, I then disassembled the tonearm board from the tonearm to make things a little easier.

Per usual, my results are in blue, and I come with photos this time!

Your two errors have a small incandescent lamp in common (under the tonearm). You should see it producing light whenever power is applied. Check for it, so you know where it is. I know it is producing light, because the end detector response shows it. The lamp is mounted in a frame, facing downwards. directly beneath it is a CdS sensor (end detector), which appears to be working.
Checked and noted lamp is illuminated

Mounted at right angles to the line between the lamp and the CdS sensor is a small circuit board. On that circuit board is a small, clear, 2-leaded photo-transistor. This photo-transistor receives light from the lamp whenever the tonearm is not in its rest. Whenever the tonearm is in its rest, there is a small shield on the pickup plate that blocks the light from hitting the photo-transistor.
You're right, that photo-transistor is a small bugger!

From your measurements, the indication is that the photo-transistor is still receiving light, even with the tonearm in its rest. Here are some possibilities:

- The pickup plate is not positioned properly
Rechecked and confirmed straight back. Note position of Allen wrench (it sagged a little when I let go of it to photograph it)

- The small light shield on the pickup plate has been broken off, or damaged (light is getting by, hitting the photo-transistor)
Intact and sound!

- Transistor Q3 is bad (shorted, or low resistance between emitter and collector)
I pulled Q3 and did the six-way diode test. It tested good.

- Some kind of solder splash in the area of R5 (1K), R6 (1.6K), Q2 (the CdS), or Q3
I flipped the board over and checked. All looked good. (Ignore the little bit of fuzz on one lead of Q3. My fault, and I removed it after the photo.)

- The photo-transistor is bad (shorted, or low resistance across its 2 leads)
This one may be a possibility, but I don't know how to correctly determine good or bad with a photo-transistor. I ended up pulling it out and first checked continuity, but that showed no continuity. I don't know if it should show continuity or not. So I then put my meter into diode mode and clipped the meter ends to each leg. In one direction I got a reading, and when I swapped meter ends to the opposite legs I got no reading.

Check those items and report back. Look below for what should be seen when working right, so you can see when you have fixed it.

- TP-5 should be around 0v (not .75v), when the tonearm is in its rest

- TP-1 should be around 0.3v (not 6.4v) when the tonearm is in its rest
Excellent, thanks, I will make that note!
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ client __________________________________

I was able to snag some time and finish the reassembly.

I did as instructed, covering up the photo-transistor with 2 layers of electrical tape. The plastic light shield that's part of the pickup plate faced upwards, of course, and seemed to block the PT as it should once I had it aligned.

Once I applied power, the platter started turning. (The usual delay of a couple of seconds also occurred.)

Then just to double check, I disassembled it again, and pulled off the electrical tape. I decided to use three pieces of tape, and again, pressing down all edges, ensuring total coverage as before.

Reassembled and applied power. Few seconds delay, and the platter started turning.

You've indicated if the platter turns, I've either got bad circuitry or a bad photo-transistor. (or both? Unlikely, I would hope)

I'm assuming that replacing the photo-transistor would be the next step, however, are appropriate photo-transistors available? I browsed through mouser.com and found some, but not having a clue as to specs, well, I didn't get far!

Or perhaps further steps are necessary before I place an order.

It feels like we're getting closer to solving this!
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ pustelniakr __________________________________


Now remove the photo-transistor, put the unit back together, and watch the platter on power up. If it does not spin, the photo-transistor was bad. If it does spin, the problem is likely Q3. Remove Q3, and reinstall the photo-transistor. If it now does not spin, you have found your problem: Q3 is leaking from emitter to collector, or it is being biased on by some sneak current coming into its base from somewhere (should only see a voltage developed across R5 when current is drawn through R5, R6. and the photo-transistor, when the photo-transistor is seeing light).

Check D2 for proper functioning as a steering diode. The delay is likely from C7 charging up with current that is coming through D2, from the leaky Q3. If Q3 proves to be bad, you will need to research to see what would be a suitable modern substitute for Q3. I don't have time to do the substitution research. Q3 should be a 2SA733P or 2SA733Q.

If the problem still occurs after removal of Q3, we are left with a couple of rather far-fetched problems to be addressed, only if needed.
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ pustelniakr __________________________________

I changed my mind. If you need to replace Q3 (2SA733P), I believe you can use a ZTX795A, available here: http://www.digikey.com/product-detail/en/ZTX795A/ZTX795A-ND/92573

Be careful, I'm not sure that the pin-out is the same between parts. Let me know if Q3 is bad, and I will do further research about pin-out. You can go ahead and buy the part, and we will determine if it is a drop in, or if we need to change how it is installed.

The photo-transistor is a more sticky matter, not to be considered unless we need to.
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ client __________________________________

pustelniakr said:
Now remove the photo-transistor, put the unit back together, and watch the platter on power up. If it does not spin, the photo-transistor was bad.

Well, for better or worse, the culprit appears to be the photo-transistor. Once reassembled and power applied, the platter did not spin. I waited a full 60 seconds to just to make sure, but it did not start up. I shut off power, waited about 10 seconds, then engaged power again, waited another 60. Still no platter rotation.

Lastly, I then cycled the power, 3 seconds on, 3 seconds off for 10 times. Keeping the power on, waited again.

No platter rotation, nor any during the power cycling.

Assuming the photo-transistor is the sole problem, I am hoping it doesn't fall into unobtanium status.

And thank you very much for the extra effort regarding Q3! I will hold off proceeding any further with that as it doesn't appear to be an issue.
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ pustelniakr __________________________________


Sorry. If the problem is indeed the phototransistor, you will need a parts unit to replace it. No one I can find makes anything close to it. It is a TPS605-Y (NPN, photodarlington, centered on 720nm, high gain, clear package, +/- 20 deg half-angle).

You will need a parts unit...
 

pustelniakr

Silver Miner at Large
Staff member
Supplemental Info:

Platter Never Stops (cont.):

____________________________ client __________________________________


She sings! I received the bracket and mini board from ___________ (I don't know if you had a hand in that, but if you did: THANK YOU!) and was able to work on my turntable late last night.

Once I removed and reinstalled, and reassembled to the point of testing, I literally held my breath when I pushed the Power button down.

3 seconds...5 seconds...20 seconds...the platter did not turn! I tapped the Up button, and swung the tonearm to the edge of the record, and it began to turn. I swung the tonearm back towards the rest, and the turntable stopped spinning. I tapped the Down button, and the tonearm came to rest.

And then the moment of truth: I tapped the Start/Stop switch. The tonearm swung over, the record began to spin, and the tonearm lowered (the drop point was off, but no biggie). I then brought the tonearm near the end of the LP and used the Down button to lower it. Once it drifted into the dead wax, the tonearm lifted and swung back nicely into the rest.

I was so excited! I grabbed a point and shoot and shot some quick video. ...Between your guide and experienced troubleshooting, this is one PL-630 that can keep playing hopefully for a long, long time.
 
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