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Marantz 6300 Project

Discussion in 'Marantz Audio' started by Echoplex, May 2, 2014.

  1. Echoplex

    Echoplex Active Member

    Messages:
    174
    Marantz 6300 Project Part 2

    I made quite a bit of progress this weekend.

    First, I got started desoldering the old caps with the Hakko 808, then cleaned off the glue from the old caps with Acetone and a gillion Q-tips. Thanks Marantz! :D Next, I recapped the power supply with Panasonic FM 105 degree caps and replaced all of the resistors with Ohmite OD Little Demons (carbon composition types); these are low noise, high temp & rapid heat dissipation. I think it turned out pretty good!

    Power Supply with new electrolytic caps, new carbon comp resistors and new SCR from ON-Semi. Most of the wire wrap connections on the pin lugs were redone as well.
    [​IMG]
    Speaking of wire wrap...the 24 awg wire is very delicate. One little twist on the board the wrong way, and snap, you'll have to do it over again. I've gotten quite a lot of practice during this project. :D If you choose to redo the wire wrap like the factory did, strip the wire about 1 7/8" long so that the wire wraps about 8 to 9 times around the pin. It comes out looking factory spec. If you have a spare unit laying around, I highly recommend practicing with it as well. Once you get the technique, it's a cinch!:thmbsp:

    After finishing the power supply board, I got started recapping the motor. I used Nichicon HE & MV series 105 degree caps with the same capacitance/voltage specs as the originals. As you can see, these are quite a bit smaller than the original ones, but they fit perfectly. If you have this particular motor version, just remember to be very careful with the soldering iron. I would suggest doing one component at a time.
    [​IMG]

    [​IMG]

    Jonard (HW-UW-224) wire wrap/unwrap tool. Life saver right here, although a little pricey.
    [​IMG]

    All in all, everything has come out good so far, but it has been a lot of work doing this project, including researching all of the component replacements, re-doing the wire wrap connections (several times) and jumping over the unexpected hurdles along the way. Thank goodness I had a spare parts 5020 deck laying around because I've used a lot of wire from it to run new wire connections on this project.

    Hope other 6300 owners are finding this thread useful and enjoyable.

    To be continued...
     

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    Last edited: May 13, 2018
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  2. Echoplex

    Echoplex Active Member

    Messages:
    174
    Marantz 6300 potentiometer cleaning / Replacement

    Making some more progress...

    I removed the potentiometers with 7/16" nutdriver and cleaned them thoroughly with DeOxit F5 cleaner and cleaned the metal outside contacts with D5 cleaner...probably overkill because I'll be replacing both of the pots with new ones from Bourns Pro Audio eventually.
    [​IMG]


    Lift each tab using a small precision screwdriver, then spray the pots thoroughly with F5 and work the dial back & forth several times.
    [​IMG]

    [​IMG]

    Close-up of the 5k pot. Marantz also used 1K pots on the 1st gen versions of the 6300. As you can see, there is some thermal discoloration on the wiper arm and the carbon trace looks a little worn.
    [​IMG]

    I finally got around to replacing the pots and these are the ones I used:

    Bourns Pro Audio
    1K potentiometers
    part # PDB181-E415K-102B (exact fit)

    [​IMG]

    [​IMG]

    Bourns also makes a 5K version:
    part # PDB181-E415K-502B
     

    Attached Files:

    Last edited: Aug 28, 2016
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  3. Echoplex

    Echoplex Active Member

    Messages:
    174
    Marantz 6300 tonearm variations (Part 1)

    The 6300 tonearm has proven to be a challenge in rewiring, re-assembling, re-aligning, and in my case, slightly modifying it a tiny bit. There are some notable variations in 6300 tonearms that I thought I'd share here for those of you wanting to do your own repairs and mods.

    Version I 6300 tonearm
    Version I has a small inner ground plate made out of brass, which also serves as the connecting joint for the tonearm and gimbal assembly fastened together with one 2mm setscrew. I’ve encountered some problems with this version due to a couple of factors. First, the brass plate is very small and doesn’t have a guiding arm to preset it into position, which causes the tonearm to have considerable lateral & vertical movement, thus making it prone to mis-alignment and cross-threading the brass plate. Second, the gimbal assembly hole diameter and tonearm wand do not fit together tightly, which also contributes to mis-alignment.

    Brass ground/connecting plate
    [​IMG]

    Version 1 Gimbal Assembly
    [​IMG]

    6300 tonearm wands: Version I (top) & Version II (bottom). The lengths of the arm wands differ by 6mm due to the way they fasten to the gimbal assembly.
    [​IMG]

    My 6300 is an early production model, thus it has the Version I tonearm. The brass connecting plate was really concerning me after encountering all of the aforementioned issues, so I got a little creative and used a ground plug from an old Technics 1200 arm I had laying around. Luckily, the plug fit since the 6300 & 1200 have very close tonearm wand diameters, with the Technics being a tiny bit larger @ 9.2-9.5mm and the Marantz being 9mm. However, the Technics plug has a larger set screw hole diameter, so I had to make a minor modification in order for it to fit properly. To do this, I drilled the gimbal assembly setscrew hole just a touch larger using a 3/32 (2.38mm) drill bit and pin vise. With just a few turns, the new setscrew fits into place perfectly and the tonearm is now better secured and properly aligned to the gimbal assembly.

    Gimbal Assembly mod using pin vise.
    [​IMG]
    [​IMG]


    Here’s the Technics 1200 inner ground plug. As you can see, it's partially concaved and shaped to the same curvature of the tonearm wand, but it also has a protruding arm that prevents it from traveling too far into the tonearm wand, which makes re-positioning it very easy. Also, on the rear of the plug, there’s another little arm that allows the ground wire to be wrapped around it, which creates a safeguard from pulling the ultra-thin 33awg wire off of it. A nice design!
    [​IMG]

    [​IMG]
    Given a choice here, if I’d had a spare intact Version II 6300 tonearm on hand, I would’ve simply installed it in place of mine, but the one I happen to have came out of an old parts unit that unfortunately is too far gone to be used. Waiting for another one to come along could take months. The real bummer is the fact that the 6300 tonearm parts are not cross-compatible between both versions. The gimbal assembly boreholes are different sizes, the tonearm wands are different lengths and the drill holes on the tonearm wands align differently. Thankfully, I found a solution that worked, but if I never have to do this again I won’t be sad!:D
     

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    Last edited: Aug 27, 2016
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  4. Echoplex

    Echoplex Active Member

    Messages:
    174
    Marantz 6300 tonearm variations (Part 2)

    Version II 6300 tonearm
    On Version II, the connecting joint/ground plug have been updated. Instead of connecting the tonearm to the gimbal assembly using the small brass plate, it was changed to a milled brass plug secured by three 2mm setscrews; two of which fasten the tonearm wand directly to the plug, while the other setscrew fastens the protruding end inside of the gimbal assembly.
    [​IMG]

    Version II gimbal assembly is now comprised of two hole diameters; the main borehole is fitted for the brass plug, while the outer beveled hole is for the tonearm wand. The easiest way to tell which version you have (without having to take everything apart) is to look at the rear tonearm wand setscrews. If there are two, then you have Version II. Lucky you!;)
    [​IMG]

    IMHO, Version II is a much better design over Version I in a couple of ways. First, it makes mis-alignment impossible as the joints fit tightly together, thus eliminating any play or movement between them. Second, the updated ground plug makes it much easier to change the tonearm wire out and reposition everything back into place, making final assembly much easier.

    Version II ground plug.
    [​IMG]
    [​IMG]


    Headshell bayonet contact pins.
    Version I
    [​IMG]

    Version II
    [​IMG]

    More to come...stay tuned!
     

    Attached Files:

    Last edited: Aug 27, 2016
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  5. Echoplex

    Echoplex Active Member

    Messages:
    174
    Marantz 6300 Tonearm rewire (Part 1)

    After doing a few trial runs, I got started on rewiring the 6300 tonearm. I would recommend ordering at least 2ft of wire if you try this because you're going to need more than enough to keep one end of the wire from sliding back through the gimbal assembly and tonearm wand as you reposition & reassemble them back into place. Trust me, 33awg is not easy to work with because it's very small and very delicate.

    Cardas Litz 33awg wire (2ft)
    [​IMG]

    Step 1:
    Even-up the Cardas Litz wire and the black ground wire (not pictured) and file them through the rear of the gimbal assembly hole. I shaped the wire on the end so that it has a slight curve to it (see pic 5). This helps to feed the wire through the gimbal assembly hole without having to fish it out with a small tool and eliminating the possibility of damaging them.
    [​IMG]

    Step 2:
    Feed the wire through slowly and do not force it, or you'll end of bending it and ruining it. Also, remember to keep the wire strands close together and twist them slightly as you're feeding them through the gimbal assembly. This strengthens the strand to act as one strand while you're fishing them through.
    [​IMG]

    Step 3:
    Continue feeding the wire through
    [​IMG]

    Step 4:
    Wire is now all the way through the gimbal assembly hole. Here, you can see what I was talking about earlier with curving the wire just slightly on the end so that it feeds through the gimbal assembly hole easier.
    [​IMG]
     

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    Last edited: Aug 27, 2016
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  6. Echoplex

    Echoplex Active Member

    Messages:
    174
    Marantz 6300 Tonearm rewire (Part 2)

    I used a cotton sleeve from partsconneXion to dampen the tonearm wand internally.
    [​IMG]

    Step 5:
    Loop the end of the Litz wire to feed it inside of the cotton sleeve, but do not tie it or bend it at a straight angle. Again, just be careful and make sure the loop is long enough that the wire can feed itself easily through the cotton sleeve.
    [​IMG]

    Step 6:
    Continue to feed the Litz wire through, while trying holding the cotton sleeve straight.
    [​IMG]

    Step 7:
    Proceed to feed the Litz wire through the cotton sleeve until the looped end is just poking out at the end, then stop.
    [​IMG]

    Step 8:
    Now feed, both the cotton sleeve and Litz wire into the tonearm wand. You'll also need a small tool to help position the cotton sleeve inside of the tonearm wand.
    [​IMG]
    [​IMG]
     

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    Last edited: Aug 27, 2016
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  7. Echoplex

    Echoplex Active Member

    Messages:
    174
    Marantz 6300 Tonearm rewire (Part 3)

    When finished with Step 8, the looped end of the Litz wire comes out looking like this.
    [​IMG]

    I positioned the cotton sleeve between the tonearm wand setscrew holes at each end so that it wouldn't get hung-up internally.
    [​IMG]


    Step 9:
    Insert the ground plug into the tonearm wand, then position the wand into the gimbal assembly and check for proper alignment.
    [​IMG]

    After verifying that the headshell angle and alignment are correct, fasten the rear of the tonearm to the gimbal assembly.
    [​IMG]


    Step 10:
    At this point, the Litz wire is ready to be soldered to the headshell bayonet contact pins, but you'll need to pre-tin the wire first. A good temp-controlled soldering iron is a must here.
    [​IMG]

    To prepare the wire, I set the temp setting on my soldering station to 780 degrees, then using the tip of the iron, melted a 1/4 inch of the enamel ends and coating off of the Litz wire (one at a time) using a bevel-type soldering tip.

    Next, I dipped each end of the Litz wire into some flux paste, then tinned each end. This really helped the process go much faster as the flux paste ensures that the solder melts onto the wire evenly, while cleaning off any contaminants.

    This part is critical: Before soldering the Litz wire onto the bayonet contact pins, remember that proper soldering temperature and speed are your friends here. DO NOT, I repeat, DO NOT leave the soldering iron tip onto the headshell bayonet contact pins for longer than a couple of seconds each, otherwise you'll melt the plastic housing and will be starting this entire procedure over again.:nono:

    In fact, before attempting to rewire your 6300 tonearm, I would highly recommend buying an old Technics 1200 tonearm to practice with over and over until you get comfortable with the procedures. The 6300 arm is similar to the 1200 arm, and if you happen to mess it up? Well, better to mess up a practice arm than the real one right? The end goal here is to gain confidence and improve your skills so you don't make the same mistake twice. :thmbsp:

    Step 11:
    Before soldering the new wire on, I attached the headshell to the bayonet connector because it protruded the spring-loaded contact pins out a little further, thus giving me more room to work with. See the photo below for reference. This also helped me remember what color wire gets soldered to each bayonet contact pin. ;) Remember to solder onto the flat part of the bayonet contact pin ONLY! DO NOT solder past that part of the contact area, otherwise the spring pin will not be able to retract as it was designed to do.
    [​IMG]

    Step 12:
    Once you have Litz wire soldered to the bayonet, grab your multi-meter and verify that you have signal and continuity on each channel before reassembling them back into place. Trust me, just do it.:D

    Step 13:
    Next, carefully re-position the bayonet back into the tonearm wand, gently pulling the excess Litz wire from the rear of the gimbal assembly out. Do not pull the wire too hard, or you'll be re-soldering everything again.

    Step 14:
    Now, the tonearm is ready to be fastened back down to the plinth. After bolting the arm back into place, check alignment again. I would highly recommend using the Sumiko HS-12 headshell because it's lighter than the Marantz headshell by approximately 2 grams and most importantly, it has adjustable azimuth making perfect alignment possible.

    More to come....
    Photo unit parts, caps list and all new equivalent replacement parts. Most are listed in this thread somewhere already, but I'll bundle them all in one post to make it easier for folks looking for that sort of thing.
     

    Attached Files:

    Last edited: Aug 27, 2016
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  8. Echoplex

    Echoplex Active Member

    Messages:
    174
    Marantz 6300 (Updated)

    Here's a pic of my finished 6300. After three and a half weeks of work, music at last!!!!:music::D
    [​IMG]

    For making the walnut figure pop a little more, I used this brand:
    Howard Restor-A-Finish in Walnut, then followed-up with Howard Feed-N-Wax wood polish conditioner.
     

    Attached Files:

    Last edited: Aug 27, 2016
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  9. Dingman

    Dingman Do you know where your towel is? Subscriber

    Messages:
    2,476
    Location:
    Des Moines, Ia
    Nice. I really appreciate your effort.
    I don't have a 6300 but I do have a 6270Q and your info will come in handy.
     
  10. Echoplex

    Echoplex Active Member

    Messages:
    174
    Thanks for the kind words. Glad you found this thread informative and helpful. That was the ultimate goal I had in mind. :thmbsp:

    FWIW, I'll be posting more stuff from the project this weekend and fixing the photos that didn't upload properly on post# 30 (Marantz 6300 Tonearm rewire Part 3).
     
    Last edited: Jun 16, 2014
  11. mikezing

    mikezing Member

    Messages:
    60
    Thank you very much for all the info! Ive been having issues with my up and down buttons recently. They no longer move the tone arm up and down. I figured id start by replacing the switches. Is the part number you found for micro-switches the correct one for the up and down buttons as well?
     

     

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  12. Echoplex

    Echoplex Active Member

    Messages:
    174
    Hi Mike,

    Yes, the Omron micro-switches (Part# VX-5-1A3) are the correct replacement switches for the 6300, though it's hard to say for sure that new switches will fix your problem.

    It sounds like the solenoid isn't getting any power or is not working altogether. Have you checked voltages there?

    Also, I would check the soldering joints at the switches first, then check the contacts for continuity. If they test fine, then your problem is elsewhere. Make sure you get the schematic and service manual and check voltages accordingly.

    Hope this helps, but again, it's hard to know for sure.
     
  13. mikezing

    mikezing Member

    Messages:
    60
    The up and down buttons no longer click when I press them and closer to the end I had to push them harder to get them to active, which is why i thought it might be a mechanical problem or the switches themselves. I will try to check continuity tonight and check voltages at the solenoid. Thanks!!!
     
  14. Echoplex

    Echoplex Active Member

    Messages:
    174
    OK. Well, in that case then the switches could be the culprit after all. They're low actuation switches and after 35+ years of use could be worn out and have oxidation on the contacts. I went ahead and replaced all ten of mine for peace of mind. They were fairly cheap from Mouser.
     
  15. mikezing

    mikezing Member

    Messages:
    60
    Checked continuity on the 7 switches I saw under there and they all seem to work...switch activated connects 2 of the posts and deactivated connects 2 different posts. They all also make a nice click sound when depressing the button.

    How do I check the voltage on the solenoid?

    I should also mention that before this happened the tone arm would raise and lower way too fast. I bought high viscosity oil and applied some to the cylinder visible when the little bumper goes up to pick up the tone arm and to the cylinder surrounded by a spring above the solenoid (when looking at it with the tt upside down). It seemed to work pretty well...the drop speed slowed significantly and the up speed slowed a bit too.

    Not sure if that has anything to do with my current problem, but thought i should mention it.
     
  16. Echoplex

    Echoplex Active Member

    Messages:
    174
    You're going to need to reference the schematic and SM in order to understand the circuits operation and to check voltages accordingly. Without those, you're going to be lost and my trying to help you is going to be futile. Sorry, I don't mean to sound harsh here, but those two items really will help you more than somebody explaining it to you sight unseen. Also, if you've never done this type of repair work before, I would not recommend proceeding any further because you could accidentally mess something else up if you aren't careful. I don't know you personally, so I'm not going to presume to know what your knowledge of electronics is. That said, proceed at your own risk.

    If you look at the schematic, you'll see that the solenoid connections are placed at junctions J808 and J807 and that the voltages at those locations should both be 35.2 volts each. Set your multi-meter to DC volts and place the common lead of the multi-meter onto the common ground of the turntable located at the upper left corner. There is a four-pin ground terminal that is shared and bolted down to the plinth near the tonearm RCA cables. Use that as the ground reference point. Then, take the positive lead of the multi-meter and place it onto one side of the junction points of the solenoid and measure the voltages for both sides, one at a time. If you get 35.2 V or something close to that, then your solenoid is getting power, but not powering on so to speak, so it could be bad. On the other hand, you may have an intermittent problem with one of the micro-switches not latching properly or something else going on altogether. Sorry, but without the unit being in front of me, it is impossible to say for sure where the problem is occurring.

    Four-pin ground terminal
    [​IMG]

    Based on your description of the symptoms, it sounds like you might have shorted the solenoid out when you put oil onto the cylinder shaft. It could have run down into it and if that's what happened, then it could have caused it to short possibly, so you may have to replace it. Where to find a new one? I would have no idea. Perhaps an equivalent replacement could be found, but that would take some time to research. I've never had to replace the solenoid, so that's uncharted territory for me.

    One other thing I forgot to mention regarding the micro-switches...
    The main control panel buttons that operate the micro-switches have spring-loaded levers that are comprised of very thin metal tabs. The metal tabs (located directly beneath the control panel buttons) are what provide the force to hold the pin plungers on the micro-switches down, ensuring full contact. Over years of repetitive use, they become bent out of shape quite easily. When this happens, they no longer provide the necessary force to hold the pin plunger on the micro-switch down, potentially causing intermittent issues, so make sure they are making full contact onto the pin plunger. I ran into this very issue with my 6300, which is why I bring it up, but be careful if you have to bend the levers back into shape because they are old and can easily break.

    I hope this helps you out, but if you have a shadow of doubt, by all means, take your 6300 to a qualified tech and have peace of mind. Good Luck!
     

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    Last edited: Aug 27, 2016

     

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  17. mikezing

    mikezing Member

    Messages:
    60
    When the table is powered on, there are 35.2v running to both sides of the solenoid using the ground pictured (pushing the up and down buttons seems to make it drop a couple volts). The mechanisms and switches all seem to work and the metal tabs seem to hit the switches properly. There is a slight bit of play in the down button, but Im pretty sure that was always there.

    I cleaned up the slight bit of grease that was on the solenoid, but im thinking the solenoid might be shot. Any other tests to be sure?

    Thank you again for all the help so far!!!
     
  18. Echoplex

    Echoplex Active Member

    Messages:
    174
    No problem, though I really don't think I've helped you all that much, but I'll try. Wish I had a suggestion on where to find a new solenoid, but Marantz did a swell job of keeping it a secret. LOL Unfortunately, there's nothing in the SM or schematic that tells a 6300 owner how to service the solenoid; what oil to use and where to use it.

    The down button switch will feel differently than the others due to how it mechanically links five of the switches, plus the solenoid simultaneously. That's a lot of stuff for one little switch button to do, but your description of it is accurate as that has been my experience with it too.

    I don't know if there's any more testing you can do because based on your voltage measurements, you're getting power at the solenoid location, but it isn't powering on, so I'd say it needs to be replaced. I don't know what else it could be? If the voltage was way off, then your problem would've been somewhere else in the circuit, but the fact that you put oil onto the solenoid shaft itself tells me that it more than likely caused it to short.

    Where's our fellow AK forumite member Restorer-John at? lol I bet he would possibly have some good ideas on where to find a replacement part or perhaps offer some additional troubleshooting advice. John, if you're reading this, can you give us any pointers on where else to look? Thanks!
     
    Last edited: Jan 26, 2015
  19. mikezing

    mikezing Member

    Messages:
    60
    I was told by someone else that a bad solenoid will usually have an OL on one side of it. He was thinking it might be the transistor in the drive circuit.
    I tested H803...34v in, 17.5 one leg, and 16.8 on the other. (the second leg should be 17v)
    H805 35.2v in and 0v on both sides

    J811 has .6v
    J805 has 1.6v (should be 1.7v)
    R802 has 35.2 before and 34v after

    in some places the voltage goes down a couple volts when the motor spins.
    Couldn't see any other spots on the schematic to test voltage. Any other help diagnosing would be greatly appreciated!! I was told by my local shop that a solenoid would be tough to find and very expensive.
     
  20. mikezing

    mikezing Member

    Messages:
    60
    I still have it apart and Im hoping someone could give me something else to try! My local shop said they would look at it for $65 not including parts or service and with no guarantee that they could actually fix it. Therefore, Im happy to try the shotgun approach and replace microswitches, transistors and whatever else is in circuit with the solenoid. Best case scenario I fix the problem and worse case I narrow it down to the solenoid and try to locate one in the future.

    What should I order and replace?
     

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