Restoring a Pioneer PL-630 Turntable

Discussion in 'DIY' started by pustelniakr, Dec 12, 2006.

  1. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    In my opinion, the PL-630 is the nicest consumer turntable Pioneer ever produced, having the same specs as their TOTL PL-C590 with its PA-5000 tonearm, with the addition of full automatic operation (and it's prettier too). This table is truly elegant in design, and for the purists who fear that the automatic functionality and mechanism will detract from the sonic performance, unless an automatic function is active, no additional mechanism is in contact with the tonearm in ANY way (the mechanism is fully retracted from the tonearm). The suspension for this table is so good, you can put it right on top of your speakers, and run up the volume...there will be no feedback or howling. My main rig will never be without a couple of these beauties.

    This thread is for those who have had a PL-630 since they bought it new, or discovered Dad's PL-630 in the closet, and want it to perform up to, or exceeding, original factory specs. After almost 30 years all of these will need some restoration operations performed on them, even if they appear to 'work'. They may work, but you will never know what they can 'do' until you bring them back up to full steam.

    Here is an overall list of operations I perform on these units, before offering them for sale (in my opinion, none are optional):

    1. Rebuild the tonearm drive mechanism (most of these units have very sluggish tonearm drives at this age, if they function at all).

    2. Supplement the rubber of the suspension boots (most are pretty dry and cracked).

    3. Replace all electrolytic capacitors (they have only a 20-30 year lifespan)

    4. Refresh all circuit board solder joints (flow-soldered joints also have only about a 30 year lifespan)

    5. Verify the power supply voltages and filtering.

    6. Clean and deoxidize all user controls (most units have dirty controls, which don't show up audibly, but in table speed instability).

    7. Perform a complete platter drive and speed meter calibration/adjustment

    8. Optimize the tonearm settings for the cartridge (VTA (vertical tracking angle), lifter height, rest height are all adjustable)

    9. Optimize the stylus drop point (where the stylus sets down on the LP)

    10. Perform a complete cosmetic detailing, including polishing out the dustcover (there are a couple of tricks and gotchas, even for this operation)
    The Pioneer PL-630 has 6 circuit boards, with 24 caps, and the parts cost for the caps alone is approximately $12.00. The labor for the complete restoration, for a good tech, will likely be 15 to 20 hours.

    The unit you will see belongs to a fellow AKr. If he decides to chime in, you will be able to get his opinion as to value and changes in performance. Here is what the unit looked like when it was all done...

    01 - Complete2.jpg

    Note: Don't attempt this job without a service manual. You'll be sorry if you do.

    Rich P
     
    Last edited: Dec 19, 2015
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  2. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Vintage Restoration Boiler Plate

    First a bit of boiler-plate DIY info:
    1. If you are an impatient individual, tending to get frustrated, and force things, or get rough. DO NOT attempt this operation. You could very easily wind up with a pretty, brushed aluminum paperweight. Generally, if a unit is fresh, and unmolested, it is less expensive for a knowledgeable tech to restore/repair. If I have to clean up a ham-handed, fumbled job, it will definitely cost ya.

    2. Make sure that your tools are in good condition. For example, if the tips of your screwdrivers are worn, you will damage the heads of your screws (some are in pretty tight), and you will play heck trying to get them out. New screwdrivers make all the difference in the world. All it takes is for your driver to slip one good time in a stubborn phillips head screw, and you could make it next to impossible to remove, and you will damage your driver as well (take a look at your old phillips screwdriver).

    3. Do not get curious about additional details of the mechanism. There are an abundance of tiny little parts just waiting to jump out of your machine and into the nether world if you are not careful or know what to expect. These little parts can be worth the entire cost of your machine, since, if you do not find them, or if you break them, you will have a non-functional unit.

    4. Unless you have an eidetic memory (photographic), take pics, notes, etc., as you go. It is not a good thing to have extra parts left over at the end of a job. I have a large supply of tiny zip-lock bags which I use to put parts from various stages of work. In this way the number of screws, or a couple of screws and a spring or c-clip will key my memory to the stage or assembly they go back into.

    5. There are no magic bullet chemicals. Use each chemical or lubricant, etc., only where it is appropriate. If not, you have a paperweight again. If you are not sure what to use where, seek wise counsel, from reputable sources.

    6. Before you do any dis-assembly or work, put a baggie over your power plug, and hold it on with a rubber band. The very last thing you want to do, is get surprised by a spark, or G_d-forbid, a jolt. Guess what...paperweight time again.

    7. NEVER force ANYTHING. If you have to force it, you are not doing it right and you will likely break something, or get a part on wrong...paperweight time again (Getting irritated at that phrase? Good.).

    8. Mickey Mouse has no part in a vintage restoration shop. NO half-tail operations, no funky monkey rigging, no time bombs for someone else to clean up. I cannot tell you how many times I have seen serious "just enough to get by" kind of repairs (blobs of glue to replace lost c-clips, weird wire twists holding on broken parts, etc.) If you break or lose something, buy a parts unit and replace it right. Chewing gum, bailing-wire rigs will ALWAYS come back to bite you.

    9. There are innumerable tricks of the trade that are too detailed to discuss in a DIY thread (how to hold a tool, how to keep a c-clip from jumping across a room, etc.). Be prepared to learn some/many of them the hard way (by experience). Sorry folks, it comes with the territory.

    10. Get a service manual. They are just too readily available to justify flying blind. If you are a cheap ________, buy one on CD. They are only around $10 on the bay. I prefer originals. The color coding in the drawings is a real help to an old man like me.

    11. Go slow. Be meticulous. Double and triple check everything. It is easier to take the extra time to do it right the first time, than to have to take the time to troubleshoot and repair any mistakes.

    12. When wires are attached to boards being worked on, try to tie them to the board, so that the wires will flex at the tie-point, rather than at their attachment points. This will keep you from making stressed connections that will break in shipment or later. Also, note wire bundle ties and remove them, to gain as free access as possible. You may be moving the boards around quite a bit, accessing top and bottom, over and over again. Please take special note, even photos, of which wires are in which bundles, and where they are tied in bundles. If you just bundle up wires to look nice, you could get wrong wires in close association with each other, and introduce hum or other kinds of noise or feedback loops.
    Last but not least...I accept no responsibility for how well or successful you may be at performing this operation. Results will vary from unit to unit, and from individual to individual. You know...some folks should simply not try this kind of work. Most folks can be successful however.

    Rich P
     
    Last edited: Dec 19, 2015
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  3. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Re-Capping: Motivations, Considerations, Results

    My experience: Recapping generally yields only an incremental improvement in the way a unit sounds, but should significantly increase the life-expectancy of a unit.

    Here are your incentives/motivations, so balance them against cost and/or effort:

    1. I have measured a large number of caps, replaced during a recap. The majority are at or below the low end of their specs, unless they are in a location where they get thermally stressed.

    2. When 'lytic caps go, as the odds of doing so rises rapidly once their rated life expectancy of around 20 years has been reached or exceeded, they go any one of 3 ways, drift out of tolerance, fail open, or fail short. They all drift, and statistically, failing open or short is about a 50/50 mix.

    3. If a cap fails open, you may notice, you may not, depending on where it is in the circuit. Generally the fault is easily repaired, with minimal peripheral damage.

    4. The main risk: If a cap fails short, it can, and generally does, take out significant associated circuitry (ie. semiconductors made out of unobtainium).

    5. Recapping is cheap, part-wise, averaging $0.35 per cap, but labor is high. A good tech can be counted to be able to replace around 10 caps per hour (including unit disassembly, cap removal, pad cleanup, cap installation, and flux cleanup). Even if the tech only charges $10 per hour, in a unit with 150 caps to replace (not uncommon on gear I work on), the labor really mounts up when it takes 15 hours to do the job. Typical modern labor costs are in excess of $60 per hour. AK restoration artists are not in it for the money (but money is nice), so we generally do not charge anywhere near that rate, but our labor is worth that rate.

    6. The MOST IMPORTANT aspect of a recap, is the opportunity to refresh all circuit board solder joints. Flow-soldered connections have only about a 30-year life expectancy. In my experience, I have solved more problems caused by old, oxidized, fractured solder joints than by failed/drifted caps. Here is where the real bang for the buck is realized, and MUST NOT be underestimated.
    With all of these aspects considered, recapping is really only a viable procedure for upper end gear, unless the gear owner is an avid collector, and wants all of a series in excellent condition, etc.

    Rich P
     
  4. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Recapping Boiler Plate

    Now a bit of boiler-plate recapping info:

    Note: Most of the original capacitor series used in these old units are long obsolete. Selecting replacements, from current manufacturers and their series, is also a task requiring a qualified tech. There are many parameters to consider (operating temp, value, value tolerance, life expectancy, effective series resistance, internal losses, size, etc.).

    I am a Pioneer specialist, so, all my work references the Pioneer parts series. This is because my master recapping database is based on Pioneer part numbers.

    The problem with most vintage gear (in excess of 25 years old), is the fact that electrolytic caps tend to dry out, since the electrolyte is moist, and must stay that way for proper function. Some caps drift severely, in the lower capacitance direction. Some caps fail open, and simply cease to perform whatever function they were designed in to do. Others that fail, do so by failing short, generally causing catastrophic damage to the unit. You may be enjoying a ticking time-bomb.

    Some will swell and leak, causing all kinds of corrosion damage to the circuit boards in the area, while others will literally blow up. Some caps measure OK on a capacitance bridge, but, in the circuit, leak DC, causing noise, bias shifting, instability, etc. I truly recommend re-capping gear you intend to keep and enjoy, or sell to someone you care about.

    Re-capping generally requires a complete service manual, with all published supplements, addendums, errata, and modification sheets. Each board is gone through, electrolytic caps are each measured to get their physical dimensions (replacements must fit in the space provided. Not to fear normally, since modern caps tend to be 1/3 the size of the originals (sometimes causing other problems)). Then the caps are checked to see which Pioneer series they are in (indicated by Pioneer part number). Now you must attempt to determine what characteristics were inportant to the designers that established a specific Pioneer part number series. Hints come from what cap manufacturer series was used (usually, and hopefully, more than one), "if" you can find the very old data sheets you need (so far all the series I've encountered have been long obsolete), or mfg-to-mfg cross-reference lists. You must also track what kind of circuits the particular Pioneer part number series is used in (coupling, de-coupling, filtering, feedback, etc.). Without the original Pioneer part drawings, you must engage in significant guesswork, supplemented by informed/experienced reverse-engineering.

    The next step is to attempt to find modern manufacturers for parts that conform to the design criteria determined in the previous step, followed by locating distributors that handle the replacement parts (in the onesy-twosy quantities you will need), and determine the per unit cost. (Note: I prefer to keep things original. I don't try to second think the original designers, unless the future owner pays significantly for an upgrade or modification. I do tend to use a bit better part than the original, but not to point of using the very expensive, esoteric, sometimes snake-oil parts. It gets to be a lot of fun when the part you need is not made by anybody in the size and/or voltage you need (like finding low voltage electrolytics in the sub-1uf values). Then you need to substitute a different kind of part altogether.

    I then created an overall Pioneer database for electrolytic caps, which I can then draw on for other models down the line, and from which, I create a model-specific database, which shows each cap, on a per-circuit-board basis, with all the associated info (original part number, dimensions, value, working voltage, new mfg part number, distributor part number, price, etc. etc. etc.). The database also contains a table of consolidated data, where all like parts are grouped, used as a purchasing list for the model.

    Here are some of my choices for the various types of caps that may need replacement:

    1. For the low leakage or low noise lytics, I use Xicon LLRL series parts.

    2. As to the standard 85degC, 20% lytics, I prefer to use the Panasonic FM series. When they are not available (possible, since this is a new series for Panasonic), I use the Panasonic FC or the Nichicon PW. They are an incremental upgrade to the originals, in that they are 105degC, lower ESR parts, low tan-theta (relating to internal losses), plus, the Panasonics are pretty, with those gold labels and all.

    3. For standard 85degC, non-polars, I use Panasonic SU. No upgrade here, but there are fewer choices in this type.

    4. For the parts "requiring" low ESR, of course I'm using the Panasonic FM, and FC Nichicon PW. No upgrades in this case, except for the temperature tolerance.
    When I order the caps for a unit, I usually order enough to do 3 or 4 units, since I usually have at least that many units of any particular model in my inventory, and I like to have the parts I need on hand when it comes time to do them. That way, I also have complete recap kits on hand for incoming restoration commissions. I also usually order at least 2 extra of any particular cap. In that way, my on-hand inventory of caps grows, at minimal cost, which helps to cover the cases where the manual states the need for one value, when a particular board/unit actually has a different value (happens when designs are changed during the production of a particular model).

    Emphasis:
    Recapping is not the panacea for modern man. Recapping is the last thing I do to a unit, other than cosmetic work and final/performance testing. I won't recap a unit, until I have determined that it is fully functional. Recapping is more for an attempt at adding longevity to the mix. The last thing you want is for a 30-year-old 'lytic to fail short (they also fail open, and drift out of spec). Recapping is not a good "repair" technique (falls in the realm of 'shotgun repair' which I hate).


    Rich P
     
  5. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Supplemental Recapping Operations

    I have done alot of recapping, and I like to test the old ones every now and then, to see what their condition was. In general, I have found that they are not far off, just at or below the capacitance spec for the parts. I have found a few bad ones. What I add, with a recap, is a retouching of every solder joint on the affected circuit boards. Here is where the real problem is, in my experience: old, oxidized, fractured, and cold, joints that have failed. The life expectancy for a wave soldered joint (used in circuit board manufacturing) is right at 30 years. They tend to oxidize, and fracture, etc. I have repaired more problems caused by bad PCB solder joints, than by bad 'lytic caps, by at least an order of magnitude. So, for me, the solder joint retouch is the more important aspect of my recapping service.

    When replacing a cap, I have found it to be best to remove the cap, then remove the solder from where the cap was. That way damage to the circuit board traces and pads are minimized. If you try to remove the solder, then get the board to let go of the cap, you will find that there is too much heat, time, and stress on the circuit boards, resulting in lifted solder pads and traces. The best method I have found is as follows:

    1. Heat one lead/pad and rock the cap out a bit on the heated side. Let the pad cool and repeat with the other lead...working from side to side until the cap comes free.

    2. Before removing the cap from where it came out, look at the cap and circuit board, to verify that the polarity mark on the silkscreen matches the polarity of the cap. If there is no polarity mark on the board, put one with a Sharpie. If the mark on the board does not match the mark on the cap, you will have to do a bit of reverse-engineering, with the schematic and board layout, to determine which is correct. Don't assume that the way it was installed was right, mistakes are made in factories all the time. The polarity marks on circuit boards vary. With Pioneer, there is generally a plus sign where the cap's positive terminal goes. Other manufacturers may use a dot, but that will generally indicate the negative terminal of the cap. The caps themselves generally mark the negative lead on the label, and make the positive lead just a bit longer than the negative one.

    3. Once the old cap has been removed, go back and remove the old solder from the board, where the cap came from. Depending on accessibility, you can use a solder sucker (plunger-type suction tool), or solder wick/braid (braided copper on a roll, impregnated with a bit of rosin flux). I usually use the wick for hard to reach places only.

    4. Form the leads of the new cap to fit the holes (so there will be some strain relief, and there will be no stress on the new joints. Then install the new cap, and solder, leaving a nice clean, well-formed, slightly concave fillet ("the bigger the blob, the better the job" is definitely a bogus concept). Trim the leads, so that there is just the slightest amount of lead left extending out of the solder joint. Do not cut into the solder joint.

    5. When all the caps (and other parts) have been resoldered, use a soft toothbrush and alcohol (Techspray 1610-P or Chemtronics Flux-Off NR 2000) and clean off all the new and old flux from the board. This will take a while, since the old stuff tends to be abundant, and doesn't dissolve as easily as it would have if cleaned off when fresh. When doing this, make sure that you do not drip off of the board into coils and pots (etc.) or other boards or into any mechanism. The flux in solution will not be kind when the alcohol carrier dries. I usually put a couple of layers of paper towel to catch the drippings.
    While you have a board loose, it would behoove you to desolder and remove any heat-sunk drivers, clean off the old heatsink grease, and apply new heatsink grease (I use Dow Corning 340). Be very careful to reassemble exactly as they were assembled. Many drivers are electrically isolated from the heatsinks, using mylar isolators or some other method. If you don't put them back together the way they were, you will let the magic smoke out when you apply power later. Putting fresh heatsink grease on will help to keep your old parts cool so they will last longer. Old, dry, flakey heatsink compound does not do its job well.

    Note: Styrol (polystyrene) capacitors are extremely sensistive to heat. They cannot tolerate temperatures above 85 degC, and will be damaged if subjected to higher temps. Soldering involves temperatures in excess of 200 degC. You must clip a heatsink clip between the capacitor and the solder joint when retouching joints associated with styrol caps. To be safe, unless a magnified visual inspection of a solder joint, related to a styrol cap, reveals the need for reflowing (oxidized, fractured, etc.), I generally mark the solder joints in close proximity, on the same trace, with a red sharpie. This is so I will not hit them with a soldering iron during the solder joint retouch operation performed on the board, once all the 'lytics have been replaced on it. The sharpie ink is usually removed when I clean off all the old flux from the board, after solder retouch. The attached image shows a couple of styrol caps, so you can recognize them...

    02 - Styrol Caps2.jpg

    Rich P
     
    Last edited: Dec 19, 2015
  6. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Visual Overview

    This is the first view of the job ahead. It is a "before" view. The 'after' view you have already seen in the 1st post. Unlike other Pioneer models, most of the boards are pretty accessible, except for the tonearm control and motor drive boards. We will need to do a bit of extra dis-assembly to get at them...

    03 - Above w Dustcover (Before).jpg
    04 - Above Lifted Dustcover.jpg
    05 - Front.jpg

    Before you ask...Yes, my bench system consists of a TX-9500-II tuner, a SPEC-1 pre-amp, and a Spec-4 power amp. Imagine what my main rig is like :)

    Rich P
     
    Last edited: Dec 19, 2015
  7. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Initial Preparation

    Here, we start getting ready to dig in...

    Remove the dust cover: Open the dustcover to relieve the spring bias from the hinges, and lift the cover off in a direction perpendicular to the top of the table.

    Remove the headshell and counterweight

    Remove the platter mat

    Remove the platter as follows:

    1. Make sure that the table is securely placed on a stable surface

    2. Press down on the plinth, to ensure that the unit does not move.

    3. Put middle finger and thumb in the holes in the platter

    4. With a careful, controlled jerking/snatching motion, pull the platter straight up (It may resist 1st couple of attempts, however, nothing is retaining it but the friction fit on the tapered motor shaft)
    Remove the 5 screws securing the motor cover plate, and remove the motor cover plate (Note the screw labelled GND in the 1st pic is different than the other 4, as it is threaded to go into metal, and attaches the baseplate ground to the metal motor cover plate for shielding.)

    Note: DO NOT power up, or run, the unit without the platter installed. It is an intrinsic part of the motor and to do so could damage the motor.

    The 1st pic shows the unit with the platter removed, marking the locations of the motor plate screws. The 2nd pic shows the unit with the motor cover plate removed.

    06 - Platter Removed.jpg
    07 - Motor Plate Removed.jpg

    Rich P
     
    Last edited: Dec 19, 2015
  8. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Internal Access

    Now it's time to get all the way in...

    The plinth is held to the base-plate by the feet, and their screws.

    Remove the front feet from the unit, by hanging the unit off the front of the bench, just enough for the feet to clear the bench. Hold the feet, to keep them from turning, and remove the long screw that is in the center of each foot. Once the screw is out, pull the foot straight down and out of the unit. It will resist a bit, but will let go.

    Remember that the base-plate comes free as the feet are removed, so when you pick up the unit to move it, put your fingers under the base-plate, not the edges of the plinth.

    Rotate the unit, and position it so that rear feet are hanging off the bench. Then remove the rear feet in the same way as the front ones.

    The base-plate is now completely free (Be careful from here, until the plinth is removed).

    Here is where most inexperienced techs mess up the beautiful front of the unit (by not padding where the front lays)...Roll up a towel and place it along the front of the unit (which is toward the rear of the bench), to pad and protect the finish of the unit's face, when the plinth is rotated up.

    Remove the power cord and interconnect cables as follows:
    1. Remove the 2 screws (indicated in the 1st pic), securing the cord cramper panel

    2. Disconnect the signal "IC Connector" from the tonearm control board (indicated in 2nd pic)

    3. Disconnect the "Power Connector" from the power supply board (indicated in the 2nd pic)

    4. Rotate the tonearm toward the motor shaft (to help the plinth to clear it as the plinth is lifted)

    5. Pivot the plinth on its front edge, lifting the back of the plinth, maneuvering it to clear the tonearm, lifting only high enough to release the wire tie securing the power cord to the underside of the plinth (indicated in the 2nd pic)

    6. The cable assy is now free. Set it to the side while retaining control of the lifted plinth.

    7. Lift the entire plinth high enough that the entire base-plate is visible, then move the padding towel onto the front of the base-plate. Set the front of the plinth directly on the padding towel and rotate the plinth to a vertical position (Be sure to pad whatever vertical support you use, to protect the top of the plinth (I use another towel).

    8. Clip the tonearm back into its rest.
    The 1st pic shows the connector and wire tie locations, as viewed from the front of the unit. The 2nd pic shows the rear of the unit, indicating the cord cramper panel screws. The 3rd pic shows the unit with the plinth lifted to vertical position. Please note the position of the padding to protect the beautiful brushed aluminum finish of the plinth.

    09 - Connector Removal.jpg
    08 - Rear Panel.jpg
    10 - Plinth Lifted.jpg

    Rich P
     
    Last edited: Dec 19, 2015
  9. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Plinth and Front Panel Removal

    To minimize the potential to damage the finish of the plinth or front panel, now is the time to just remove them from danger...

    Remove the 5 screws securing the plinth to the front panel (indicated in the 1st pic)

    11 - Plinth Screws.jpg

    Carefully maneuver the plinth off of the front panel (pulling the front panel slightly back, then the plinth should lift straight off). The 2nd pic shows the unit with the plinth removed.

    12 Plinth Removed.jpg

    Remove the screws securing the front panel to the user control assys (indicated in the 2nd pic): 5 for the speed control assy, 4 for the tonearm control assy, 3 for the power control assy. Be careful to capture the switch caps on the power control assy (If they hit the ground, they will be cosmetically damaged)

    Remove the front panel. Set the plinth and front panel in a safe place and cover them.

    Rotate the user control assys, and lay them on the front padding, as shown in the 3rd pic

    13 - Front Panel Removed.jpg

    Rich P
     
    Last edited: Dec 19, 2015
  10. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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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.

    Carefully slide each spring out of its rubber boot (Note: try to minimize the boot's crumbling in this process)

    The 1st pic shows the suspension components (Note my location marks on the springs). The 2nd pic shows some typical boot rot.

    14 - Suspension Parts.jpg
    15 - Boot Rot.jpg

    Make some rolled forms out of cut up 3x5 cards, and slip the boots on the forms (to hold them in the right shape while we augment them). If your boots are broken up in pieces, find all the pieces, associate each piece with its boot, re-assemble them with careful application of superglue on the edges of the pieces (fun, a sort of high tech jigsaw puzzle). Then, using a putty knife cover each boot surface with black RTV, filling all cracks and making as smooth a surface is you can. Do this in several stages if the damage is extensive, letting the RTV cure between each stage. (Note: You can't make this pretty, so don't worry about that, just get a nice, even, thin augmentation done).

    Rich P
     
    Last edited: Dec 19, 2015
  11. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Tonearm Assy Inversion

    In order to begin rebuilding the tonearm drive, the tonearm drive assy must be inverted, as follows:
    1. Pad the motor and center area of the base-plate, to cosmetically protect the tonearm assy (I use another towel or 2)

    2. Remove the 4 screws securing the tonearm assy to the base-plate (indicated in the 1st pic): 3 in the tonearm housing, and 1 in the corner of the tonearm drive board.

    3. Remove the 2 screws securing the tonearm assy wiring to the base-plate

    4. Make sure the tonearm is securely clipped into its rest

    5. Invert the tonearm assy to reveal its underside (as in the 2nd pic)
    16 - Tonearm Assy Mt.jpg
    17 - Inverted Tonearm Assy.jpg
    Rich P
     
    Last edited: Dec 19, 2015
  12. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Tonearm Drive Assy Removal

    In order to gain access to the tonearm lifter for service, it is necessary to remove the tonearm drive assy (a grouping of nylon wheels and cams):
    1. Remove the c-clip and polyethylene washer (indicated in the 1st pic), retaining the tonearm drive assy on its shaft.

    2. Rotate and maneuver the tonearm drive assy from its shaft, as seen in the 2nd pic.
    A bit of instruction here (refer to pic 2):
    • The indicated "Drive Contact Roller" is the only place that tonearm drive contacts the tonearm assy (along the indicated "Drive Edge"), ever, and that is rotated out of contact unless the tonearm is being actively driven. So, no nasty automatic arm effects on the sound of the table.

    • The PL-630 lifter shaft does not require ANY damping fluid to leak out (instead it is lubricated), because the indicated "Lifter Shaft" rides on the indicated "Lifter Ramp", which accurately and repeatably governs the speed at which the stylus is set on the LP (very elegant design).
    18 - Drive Retainer.jpg
    19 - Drive Assy Removed.jpg

    Rich P
     
    Last edited: Dec 19, 2015
  13. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

    Messages:
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    Location:
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    Clean & Lube Tonearm Lifter

    Now it's time to make sure that the tonearm lifter is clean and free...
    1. Restore the tonearm assy to upright, loosen the lifter setscrew (indicated in Pic 1), move the tonearm toward center and maneuver the lifter arm out of its shaft.

    2. Return the tonearm back to its rest and clip it in

    3. Invert the tonearm assy again.

    4. Remove the 3 screws securing the tonearm drive motor to the tonearm assy (indicated in pic 2), and lift the motor free, letting it hang by its wires (as seen in pic 3)

    5. Remove the c-clip, collar, & spring from the lifter shaft (indicated in pic 3, but be careful, parts want to jump off and hide here), then slide the lifter shaft out the "top" of the tonearm assy. Do not try to remove the shaft out the bottom, because the setscrew hole in the top of the shaft will score the lifter cylinder wall (bad news).

    6. Clean the lifter shaft & its cylinder (use a cotton pipe cleaner, soaked with lube, not solvent), then rub a slight amount of sewing machine oil on the shaft (NOT damping fluid!).

    7. Reinstall the shaft from the top, and reinstall the lifter spring, collar, and c-clip.

    8. Reinstall the lifter arm and secure with its setscrew.

    9. Put a tiny drop of Teflon lube (Tri-Flow or the like) on the motor shaft bushing, then reinstall the tonearm drive motor.
    As long as you are here, perform the following operations:
    1. Replace the 2 tonearm position sensor micro-switches (Omron SS-01GP). Use gold contact switches to minimize potential for future contact corrosion

    2. Scrub the small rubber drive pulley on the tonearm drive assy with rubber rejuvenator (Rubber Magic, or Rubber Renue), but do not get any on the nylon parts, only on the rubber.

    3. Clean off the old waxy lube from the tonearm drive screw & replace with fresh white lithium grease.
    20 - Lifter Setscrew.jpg
    21 - Motor Screws.jpg
    22 - Drive Motor Removed.jpg

    Rich P
     
    Last edited: Dec 19, 2015
  14. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

    Messages:
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    Location:
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    Tonearm Control Board Work

    Now it's time to work on the tonearm control board...
    1. Record the way that the tonearm signal wires are soldered to the tonearm control board and de-solder them.

    2. Remove the screw holding the optical position sensor assy to the tonearm assy base (indicated A in pic 1)

    3. Remove the 2 screws holding the tonearm control board to the tonearm assy base bosses (indicated B in pic 1)

    4. Loosen the setscrew holding the optical pickup plate to the tonearm shaft (indicated in pic 1)

    5. Note orientation of pickup plate, optical sensor assy, and tonearm control board, then maneuver the pickup plate and control board free (pic 2)

    6. Inspect the Optical pickup plate for cracks where the setscrew secures it to the tonearm shaft (see pic 2), which would inhibit tightening the pickup plate in position on the shaft (most units are cracked here). If the pickup plate is cracked or showing signs of stress, it will have to be repaired/reinforced. This is a complicated enough procedure to require a separate thread (coming later, next time I have to do one, since this unit is a rare one without the cracks)...

    7. Scrub the tonearm drive edge (indicated in pic 2) with high purity isopropyl alcohol.

    8. Replace all the 'lytic caps, refresh all the solder joints, & clean off all old flux. (Be careful. There are a couple of non-polar 'lytics on this board). Pics 3 and 4 show the board, before and after recap (not too dramatic since all caps are quite small to start with)

    9. Slip the pickup plate back on the tonearm shaft, while maneuvering the board back into position (be sure to get the pickup plate back within the optical pickup assy. Then, re-secure the optical pickup and board to the tonearm base.

    10. Ensure that the tonearm is locked in its base, then re-position the pickup plate on the tonearm shaft, so that it is located in the middle of the space in the optical assy, and the setscrew is aimed directly to the rear, then gently tighten the setscrew to hold it in place (we will fine tune this position when we get the tonearm assy all back together...) DO NOT over-tighten this setscrew, or you will crack the pickup plate (bad news). Just tight enough so that it does not slip around. It bears no mechanical load, so firm hold is all you need.

    11. Reattach the tonearm signal wires to the control board.
    23 - Drive Board Removal.jpg
    24 - Drive Board Removed.jpg
    25 - Tonearm Control Board (Before).jpg
    26 - Tonearm Control Board (After).jpg

    Rich P
     
    Last edited: Dec 19, 2015
  15. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

    Messages:
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    Location:
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    Tonearm Drive Reassembly

    Complete the reassembly of the tonearm drive as follows:

    1. Rub a light coat of silicone grease on the shaft for the tonearm drive assy.

    2. Put a thin layer of silicone grease along the lifter ramp edge on the upper side of the tonearm drive assy (get NONE on the rubber drive roller)

    3. Manuever the drive assy onto its shaft (past the sensor switch buttons, tonearm drive edge, and pickup plate), and retain with its polyester washer and c-clip (be careful, it flies).

    4. Remove the tonearm drive belt, scrub the drive surfaces of both belt pulleys with Isopropyl alcohol, then install a new belt (available from Vintage Electronics).

    5. Return the tonearm assy to upright position, and secure it back to the baseplate. Then re-secure the tonearm assy wiring to the baseplate.
    Rich P
     
    Honomo likes this.
  16. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

    Messages:
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    Location:
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    Power Supply Work

    1. Remove the 2 screws securing the power supply wire bundle and ground lead to the baseplate.

    2. With needle-nose pliers, compress the plastic retaining clips holding the power supply board to its standoffs. Then lift the power supply free, rotating it up to expose the solder side.

    3. Replace all the 'lytic caps, refresh all the solder joints, & clean off all old flux and adhesive under the bigger caps. The newer caps are small enough to not need the adhesive, plus it gets corrosive over time, so its best not to use it. Pics 1 and 2 show the board, before and after recap (pretty dramatic difference here)

    4. Replace the old heatsink compound under the heatsunk regulators (be careful to reassemble properly or else...)
    27 - Power Supply (Before).jpg

    28 - Power Supply (After).jpg

    Rich P
     
    Last edited: Jun 10, 2016
  17. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Platter Drive Work

    1. Remove the 3 screws securing the motor to the baseplate

    2. Remove the 2 screws securing the oscillator board (small board next to the motor drive board)

    3. Compress the plastic retaining clip securing the motor drive board to the baseplate.

    4. Pad the areas to receive the top of the motor assy as it is inverted to expose the solder side, then invert the motor assy.

    5. The caps indicated in pic 1 are very hard to access for replacement, as the solder joints are located between the motor flange and the circuit board. The motor drive board cannot be safely removed from the motor, so the caps will have to be replaced the hard way...

    6. Heat the solder joints for the test point posts (LA, LB, LC) indicated in pic 1, and pull the posts out the top of the board (carefully!), as the posts are in the way to access the hidden cap joints.

    7. Put a long, thin soldering tip on and get some light in there, rocking the caps out as usual. Then desolder with solder wick. Replace the difficult caps, reforming and pre-trimming the leads so they do not contact the motor flange.

    8. Reinstall the test point posts and solder in place easier said than done, eh?)

    9. Replace the rest of the lytic caps normally, refresh all the solder joints, and clean off all the old flux. Pics 1 & 2 show the motor drive board, before and after recapping.
    29 - Motor Drive (Before).jpg

    30 - Motor Drive (After).jpg
    Rich P
     
    Last edited: Jun 10, 2016
  18. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    Location:
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    Oscillator Board Work

    The oscillator board only has 1 'lytic on it, and it is already free...

    1. Replace the 'lytic cap

    2. Refresh all the solder joints, but stay off the solder joints for the heat-sensitive styrol cap (indicated in pic 1), and any solder joints that would cause the leads of the styrol cap to be heated (more than 85degC and that cap goes bye-bye)

    3. Clean off all the old flux.

    4. Re-secure the motor, motor drive board and oscillator board to the baseplate.
    Pics 1 and 2 show the oscillator board, before and after recap

    31 - Oscillator Board (Before).jpg

    32 - Oscillator Board (After).jpg

    Rich P
     
    Last edited: Jun 10, 2016
  19. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

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    User Control Work

    1. Remove and disassemble the power switch. Clean the contacts with thin strips of 1500 grit silicon carbide paper. DO NOT use DeOxit here. You will be sorry later if you do. DeOxit is NOT for high power switches, as it will burn due to arcing and coat the contacts with black tar (bad news).

    2. DeOxit the 'Auto' slide switch

    3. Do nothing to the disk size and repeat buttons. DeOxit is no good for snap dome switches.

    4. Desolder the speed meter from the board (meter winding contacts are all that is holding it on). Set the meter aside, so it does not get damaged by what we are about to do (wicking of fluids, etc.).

    5. Recap the speed control board, refresh all of its solder joints, and clean off all the old flux.

    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.

    7. Deoxit the speed adjust pot.

    8. If the meter lamp was out (I have never seen one out), replace it. It is an 8v, 100mA lamp (available from AKr, DGWOJO).

    9. Reinstall the meter.
    Pics 1 & 2 show the speed control board, before and after recap

    33 - Speed Control (Before).jpg
    34 - Speed Control (After).jpg

    Rich P
     
    Last edited: Jun 10, 2016
  20. pustelniakr

    pustelniakr Silver Miner at Large Super Mod Subscriber

    Messages:
    6,678
    Location:
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    Motor Calibration

    The motor calibration is detailed well in the service manual, so I won't repeat it here. However, I will offer a few tricks of the trade:

    You will need a frequency counter and a good, dual trace scope with 'A Intensified by B' and 'A Delayed by B' capability, in order to get the resolution you need to do the D.D. Motor Operating Point, which you should do 1st. Pic 1 shows what the Operating point will look when properly set for each speed.

    35 Operating Point Display.jpg

    The pots on the circuit boards are touchy, and would have been better served by 10 or 20 turn pots...Oh well.

    The "Speed Adjustment When Quartz Lock is Off" and "Sensitivity Adjustment of Cds Cell" adjustments are not necessary, so skip them.

    The user 'Pitch Control' pot is not wound linearly, but has a zone of a few degrees in the middle of rotation, where minimal change occurs in speed as the pot is rotated. This is so the user can zoom right in on the right speed when quartz lock is off. So, when the manual says to set that pot to its midpoint, you want to set it right in the middle of that zone. The way you find it is to power up the unit, and turn quartz lock off, and rotate the pot through its range. The zone will be come evident if you watch the meter. The point on the pot is not likely to be at zero on the meter, but you will fix that when you do the Meter/Speed adjustment.

    To perform the speed adjustments, you must make sure that the padding that the control boards are sitting on will also keep the boards from shorting to the baseplate. You will need to put the platter and mat on with test leads connected to various points under it. Make sure the leads do not rub under the platter as it turns.

    You will also need to connect the power cord and signal cable up to their connectors on the power supply board and tonearm control board. Now is a good time to DeOxit the connector contacts, followed by a Pro-Gold treatment (especially important for the tonearm signal wiring). Make sure the cables do not rub under the platter as it rotates.

    When the electrical adjustments are complete, put some glyptol on the adjustment pots, to keep them from vibrating off their new settings. I use GC - Red Insulating Varnish for glyptol.

    Rich P
     
    Last edited: Jun 10, 2016
    Ricktptman likes this.

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