Magnet shift repair is easy...

2

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  • K_M
    K_M Posts: 1,629
    edited September 2017
    8u1oang9me13.jpg
    Curious, why not remove the dust cap, so the alignment can be visually seen or shims placed around the voice coil to get a more precise alignment?
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  • FestYboy
    FestYboy Posts: 3,861
    2 reasons really: even if I hinged the dust cap for a visual alignment AND used shims, I'd still have to test it sonicly and tweak the alignment... And I didn't want to possibly screw that up as well and there be a visual difference between the drivers. Not cutting the cap saves that step, and time associated.
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  • K_M
    K_M Posts: 1,629
    ^^^ Either way, looks quite tedious!!
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  • FestYboy
    FestYboy Posts: 3,861
    edited September 2017
    Surprisingly, the worst and most wracking part was picking and modding the PVC... All the rest was comparatively easy. Now that I have an idea of what to do, the next one I run into should take about 10 min to fix (not including dry time of course).

    Well, it's been 12 hrs, gonna check on it now... :#
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  • FestYboy
    FestYboy Posts: 3,861
    Success!!! Better than new now (as far as my OCD is concerned).
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  • lawdogg
    lawdogg Posts: 455
    Sweet! Nice work.
    <3 my 3.1TLs

    I will fix your shifted magnets for free. :)
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  • JayMX
    JayMX Posts: 446
    I did the same thing the other day, 3 pieces. Attempt #1 - I tried gluing the poll piece to the magnet, but trying to move the entire thing and align the VC in the gap between the magnet and the PP is nigh upon impossible. So I popped the glue (hoping to not break the magnet) - sharp blow on a flat head screwdriver placed between the magnet and PP - and started over. Attempt #2 - I glued the magnet to the basket, then applied powergrab to the lower joint prior to trying to align things. Waited for it to dry and then redid my jig so the lower screws pressed against the magnet and the upper screws moved the PP only. Pretty soon she was singing like she should... Just wish I hadn't spent 4 hours on method #1 before I tried method #2! I also put a buttload of powergrab on the aligned driver while it was in the jig. Didn't turn out pretty, but it didn't shift after I released the jig! Driver saved!
    Also wish I'd used heavier pipe like you did. The green stuff I had in the scrap pile worked, but it flexed a lot! More rigid stock or a coupler would have been better.

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    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (4x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • FestYboy
    FestYboy Posts: 3,861
    Might I suggest red Loctite instead, then use the power grab afterwards. Much less messy. Also in your case, a 6 point screw system would spread the load more evenly. I would have preferred to do that as well but the coupler had 8 grooves to make accurate pilot holes so I went with 4 cuz I'm lazy, lol.
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  • JayMX
    JayMX Posts: 446
    It worked and the speakers turned out pretty and sounded pretty. That's what matters!
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (4x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • JayMX
    JayMX Posts: 446
    m1a0cnrlt6ed.jpg
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (4x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • FestYboy
    FestYboy Posts: 3,861
    JayMX wrote: »
    It worked and the speakers turned out pretty and sounded pretty. That's what matters!

    I'm not knocking it, if the goal was reached, then that's a win. Just from your pics and post, it seemed to me that a 6pt system and red Loctite would work a bit better for the given piece of PVC. I'll be doing the power grab as well a bit later down the road when I mod the XOs, then they'll be put into service likely as my front mains. The odd ball 7 I have will be seeing CC duty as well.
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  • JayMX
    JayMX Posts: 446
    FestYboy wrote: »
    JayMX wrote: »
    It worked and the speakers turned out pretty and sounded pretty. That's what matters!

    I'm not knocking it, if the goal was reached, then that's a win. Just from your pics and post, it seemed to me that a 6pt system and red Loctite would work a bit better for the given piece of PVC. I'll be doing the power grab as well a bit later down the road when I mod the XOs, then they'll be put into service likely as my front mains. The odd ball 7 I have will be seeing CC duty as well.

    It's all good! Im cheap and lazy. I used superglue for the temporary adhesion then the powergrab. I'll give the red loctite a shot next time. But hopefully there won't be a next time... I'm really enjoying my time with these old girls. Got my eye on a pair of SDA CRS's - don't tell my wife!
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (4x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • FestYboy
    FestYboy Posts: 3,861
    Your secret is safe with me ;)
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  • Lincolnhenry
    Lincolnhenry Posts: 3
    Hey JayMX, I also have a MW 6503 that needs magnet alignment but I'm not 100% on the steps you took prior to putting on the jig and putting the screws to it...are you removing that top plate with the sticker on it first, via a hammer and screwdriver? Or was that just an unnecessary step and you really just needed to put on the pvc jig and screws on the magnet and top sticker plate? I've looked at a ton of these threads and I can't seen to find a complete list of the steps. And are you tightening the screws on just the magnet or the top plate with the sticker on it? Sorry for all the questions but it's just a mystery to me how all you folks are getting from a to z in this repair.
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  • FestYboy
    FestYboy Posts: 3,861
    Which side of the magnet is loose for you? If it's the base plate of the basket, I'd think you'd want to split the motor in 3 pieces and then work your way from the basket out, centering as you go. If it's just the pole plate, then the rig I built will get you there fast and accurate.
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  • Lincolnhenry
    Lincolnhenry Posts: 3
    None of the magnets are loose as far as I can tell. The voice coil is rubbing and so the possible solution is to use this jig, correct? So if I'm not sure which piece is causing the alignment issue, you think I should split the motor into the 3 pieces and replace piece by piece as I get the alignment just right so I don't hear any more voice coil rubbing?

    How would I know of its just the pole plate that's out of alignment? I assume that's the top plate with the sticker on it?

    Also, what's the best method for splitting the motor up? Screwdriver/chisel and hammer?
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  • [Deleted User]
    [Deleted User] Posts: 0
    By nature, I'm a tinkerer and like to figure $hit out. But this all sounds like too much BS to me. Either pay someone else to do it for you or replace them is my thinking. I've got a few 6503's with shifted magnets I have no desire to try to fix. They were simply replaced and extras purchased that got epoxied and Dynamatted when I got them sitting in storage. I've got plenty of things to piss me off. Don't need to add to the list trying to recenter a charged magnet on steel plates.
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  • Lincolnhenry
    Lincolnhenry Posts: 3
    Ha, yeah I was not confident I'd be able to fix it, and was mostly resigned to having to purchase a new set. Couldn't hurt to try I figured, it's already useless. Tried to remove the top plate, got it off, then tried setting it back in. Woofer completely seized up. Pulled the plate back out and ripped the voice coil out. Oops. Good learning experience though, now I know how these things are constructed first hand. How you guys pull off this fix is beyond me...and I'm pretty good at fixin' stuff.
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  • xschop
    xschop Posts: 5,000
    I've got one 6510 with a shifted magnet. I would like to get a few more before I machine a jig to confirm that their Magnet ODs are 3.31" also.
    Don't take experimental gene therapies from known eugenicists.
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  • FestYboy
    FestYboy Posts: 3,861
    Slapaho wrote: »
    By nature, I'm a tinkerer and like to figure $hit out. But this all sounds like too much BS to me. Either pay someone else to do it for you or replace them is my thinking. I've got a few 6503's with shifted magnets I have no desire to try to fix. They were simply replaced and extras purchased that got epoxied and Dynamatted when I got them sitting in storage. I've got plenty of things to piss me off. Don't need to add to the list trying to recenter a charged magnet on steel plates.

    Send them my way...
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  • JayMX
    JayMX Posts: 446
    Lincolnhenry wrote: »
    Hey JayMX, I also have a MW 6503 that needs magnet alignment but I'm not 100% on the steps you took prior to putting on the jig and putting the screws to it...are you removing that top plate with the sticker on it first, via a hammer and screwdriver? Or was that just an unnecessary step and you really just needed to put on the pvc jig and screws on the magnet and top sticker plate? I've looked at a ton of these threads and I can't seen to find a complete list of the steps. And are you tightening the screws on just the magnet or the top plate with the sticker on it? Sorry for all the questions but it's just a mystery to me how all you folks are getting from a to z in this repair.

    I didn't have to separate anything - cabinet abusers did that for me... :| but hey I was fixing up $40 Monitor 10’s I bought from a dude in a trailer park, so what did I really have to lose?

    As detailed above my first attempt failed and I had to start over... My successful process was as follows:

    I aligned (eyeballed) the magnet so it was centered around the VC, then I glued the magnet to the baseplate. FestYboy suggested loctite red instead of the superglue I used. Refarding the jig, once you've built yours up - detailed in lots of other threads - some use two rings of 4 screws, some use 6 - I got it done with 4 but it would have worked better with thicker heavier PVC or a coupling of some sort.

    With care, I pushed the cone up inside of the magnet so it stuck out as far as it would safely go. Then I slid the backplate/poll piece into the VC hoping to avoid a good finger pinch and scraping up the VC when the magnet grabbed the poll piece.

    I then slid the jig over magnet and used the lower set of drywall screws to center and "bind" the jig to the magnet. The upper ring of screws were aligned to push against the outer edge of the backplate/pole piece.

    I played some full range music (directly from my receiver - not through the cabinet’s crossover) at low levels through the driver while I adjusted each of the upper screws, sliding the poll piece and listening as I went. It took a while, but eventually no more scratching and the volume increased dramatically as she came into alignment. Once I felt that things were better, I used a free app I found for iOS called SignalGen - a sweepable tone generator, fed into the receiver and I tested the driver (carefully) from ~60hz up to ~16khz (my ears don't hear much above 16k anymore and I doubt these ol drivers reproduce much in that range anyways... )

    At that point, I liberally applied loctite powergrab and left it for 24hrs. In retrospect the loctite red would have been much better for sticking the poll piece to the magnet because applying powergrab when the jig is still on was hard to do and very messy. Nonetheless, she held and plays great now.

    It was quite a process, fun and annoying, but very rewarding when she was mounted back in the cabinet and started to sing again like she should!
    Current Collection: Monitor 4a (Peerless), Monitor 5B (Peerless), Modified Monitor 7b (Peerless), RTA15TL (SL3000), SDA CRS+ (194’s), SDA SRS 2.3TL, R100's, R200’s, R300 🤩
    Pairs that have passed through: Monitor 4b (Peerless), Monitor 5a (Peerless), Monitor 5b (SL1000), Monitor 5b (SL2000) (4x pair), Monitor 7b (Peerless), Modified Monitor 7c’s (194’s), Monitor 10a (Peerless), Monitor 10b (5x pair), RTA8, RTA8TL, RTA 11T, RTA12c (194's), SDA CRS, SDA 2 (2x pair), SDA 2a, SDA 2b, SDA 1b, SDA 1c, SDA SRS 2 (2x pair), SDA SRS 3.1TL (198’s) (2x pair)...and more to come, it’s a sickness.
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  • pitdogg2
    pitdogg2 Posts: 25,436
    Red loctite is the correct glue to use. It is made for anaerobic conditions and metal use.
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  • Tony M
    Tony M Posts: 11,151
    Well, it's my turn to get help or make a jig myself. I have a long 10' piece of 4" pvc out back to cut a piece off of.

    1 1/2" piece is what I should cut off, right?
    Most people just listen to music and watch movies. I EXPERIENCE them.
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  • Tony M
    Tony M Posts: 11,151
    DUH....1 3/4" I see up on page one!.

    I'm going to research some more. Been busy this morn and outside this afternoon already.

    Now to research some more! B)
    Most people just listen to music and watch movies. I EXPERIENCE them.
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  • Schurkey
    Schurkey Posts: 2,101
    edited May 2019
    pitdogg2 wrote: »
    Red loctite is the correct glue to use. It is made for anaerobic conditions and metal use.
    WHICH "Red Loctite" do you mean? There's lots of them, and NOT all of these would be suitable.
    262
    2620
    263
    266 (red-orange)
    087 (red-fluorescent)
    277
    271 (Mil-Spec)
    272
    2760
    GRD A
    2045

    When it was me, I used a less-expensive (3M TL71) equivalent to the common Loctite 271 high-strength, low-viscosity anaerobic thread locker.

    This is exactly like talking about "Powergrab" but not specifying an item number, when there's a dozen varieties and again, not all of them are suitable for our purposes.
    https://forum.polkaudio.com/discussion/170827/loctite-henkel-power-grab-for-speaker-magnets/p1

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  • easyrhino
    easyrhino Posts: 7
    Just had a really nice pair of RTA 11TL's end up in the back of my truck. Probably paid to much for them but I didn't think $150.00 was to bad. Wasn't looking for speakers but I liked the look of them and they were in great shape. Finally got them fired up and found one of the MW6510 drivers is dead. Driver itself looks fine so is it safe to assume the magnet has shifted? Besides not functioning are there any visual signs of magnet shift? I'm fairly handy but the most I've ever done with speakers is refoam a few sets. Should I give it a shot????

    Also, I'm assuming it's a good idea to run some loctite around the other three to prevent magnet shift?
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  • xschop
    xschop Posts: 5,000
    Take it out and check for continuity.
    Don't take experimental gene therapies from known eugenicists.
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  • pitdogg2
    pitdogg2 Posts: 25,436
    evenly push in/out with fingers around the dust cap. If magnet shift you'll feel scratchiness or it will not move in or out. IF it moves freely it's safe to assume it is blown. if it ohms out at zero, then it is toast.
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  • easyrhino
    easyrhino Posts: 7
    edited February 2022
    Thanks guys. Lawdogg was helping me out and we determined that the voice coil is toast. Kind of a bummer cuz these old RTA's are in fantastic shape. Gonna start my search for a stock replacement. Anyone know what other Polks ran the WM 6510's just in case I run into a cheap old set?
    Post edited by easyrhino on
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  • easyrhino
    easyrhino Posts: 7
    Ended up disconnecting the same driver on the other RTA 11TL and they actually still sound pretty good with one each. Gonna use them as surrounds in my main system for a while:)
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