replacement cone/coil kits for monitor 10, 6.5" mid/woofers?

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jayward
jayward Posts: 31
edited October 2022 in Vintage Speakers
hi guys... i have a nice set of these i've finally got around to working on and all 4 mids are blown... i'd really like to rebuild them... they are so bad that 2 have almost no coil resistance in ohms, and 2 are off the charts... lol... someone must have had a real good time frying them... otherwise they are in nice shape... 3 of them still have the stickers on the back, and are listed as driver model mw 6505, no ohm rating or wattage, etc... i also own a set of 5jr's which are in good shape and sound incredible! i'd really like to hear the 10's! any help would be appreciated! btw, the 10's are from 1985, and i'm guessing the 5's are from around the same time... maybe a few years older... i found stickers with the dates inside the 10's but haven't ever took the 5's apart... well, thanks again! looking forward to getting them working!
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Answers

  • F1nut
    F1nut Posts: 49,804
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    The MWxxxx model is printed on the magnet label. Get that info and hit eBay.
    Political Correctness'.........defined

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  • jayward
    jayward Posts: 31
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    oh, sorry, i meant to add that and will try to edit my post... mw 6505... and with a decent amount of looking online, i found nothing... lol
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  • pitdogg2
    pitdogg2 Posts: 24,582
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    MW6505 ?
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  • Toolfan66
    Toolfan66 Posts: 16,915
    edited October 2022
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    6505? You mean 6503’s? You have pictures?
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  • F1nut
    F1nut Posts: 49,804
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    There never was a 6505.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • jayward
    jayward Posts: 31
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    sorry, it was dark last night when i posted this... i guess i'm in denial about how bad my eyes are getting in my old age... lol... yes, they are 6503's... i went to take pics for you guys, and looked with a magnifying glass when doing them... so i won't bother to post those...
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  • Gardenstater
    Gardenstater Posts: 4,187
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    @xschop has replaced coils with ones from eBay/China but IIRC it was not an exact match and required some machining (?).
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
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  • jayward
    jayward Posts: 31
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    yikes, i don't have machine equipment... hope that's not all that's out there... sad thing is i actually got 2 free sets of 4 6.5's, but none of them fit the holes/recesses, for the speakers in the box... they are just a tad too big... i was hoping to at least try a set of them in there to get an idea of the sound...
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  • xschop
    xschop Posts: 4,704
    edited October 2022
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    Are you sure a couple of them haven't just shifted magnets?

    The 6503 or 6510 can have an 6.7 ohm Wuhan coil replaced with no machining to the pole-piece. They have to be 25.9mm or 26mm ID in the description 32-35mm long is the best total length.
    Don't take experimental gene therapies from known eugenicists.
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  • jayward
    jayward Posts: 31
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    i don't think so... the magnets seem firmly attached... i tried pulling them apart after reading about that... 1 of them i can actually hear burnt wire banging around in the voice coil... i tried the battery test to see what i got out of them, and they didn't move, and either made no sound at all, or sounded very beaten up and pathetic... like faint clicking... you can lift the cones up, but you can't push them in... and they really don't have any recoil to them...
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  • jayward
    jayward Posts: 31
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    also curious if anyone knows how many ohms they are supposed to be? mine don't say anything on them as far as that goes and none give an accurate reading, obviously...
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  • Gardenstater
    Gardenstater Posts: 4,187
    edited October 2022
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    6.54 ohms.

    The magnetic force would make them seem firmly attached even if the magnet/pole piece had shifted.

    Don't try the battery test if they don't ohm correctly.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • jayward
    jayward Posts: 31
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    interesting... well, i figured i could pull them apart if there was no glue holding them together... so how would i know if they shifted then? also, i can clearly hear wire in at least 1 of them, and i can move the cones... i'm certainly no expert, but i'm pretty sure these are just super fried... when i got them, i think 1 made some sound, but also sounded on it's way out... the rest, i think had absolutely nothing... i haven't tried to play anything through them since digging them back out again...
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  • Gardenstater
    Gardenstater Posts: 4,187
    edited October 2022
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    You say two have "off the charts" resistance. Are you saying there is a measurable resistance? The other two have a small resistance? What are the exact readings?

    I wouldn't doubt that the two with small resistance are damaged voice coils. The thing is that could also happen along with magnet shift.

    What I would do is remove the dust caps, starting with those two. You would have to do that to align the pole piece as well as a fist step to replace the voice coils if you felt that ambitious. When you do that you can see if the pole piece is shifted.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • jayward
    jayward Posts: 31
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    i seem to be getting some different readings today... maybe since i bit them with the battery a couple times... anyway, 3 show nothing, and 1 shows @ 6.7 - 7.2... seemed to test out the most times around 6.8 on average... is there a safe way to remove the dust caps without doing much damage?7ckesao0jbsu.jpg
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    i'm pretty handy and have good tools...
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  • Gardenstater
    Gardenstater Posts: 4,187
    edited October 2022
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    If that is how your meter shows infinite resistance and the tinsel leads are not visibly damaged or misconnected, then most likely those 3 are burnt or broken coils as you surmised.

    It seems like you may only have one driver that is salvageable without VC replacement. Your meter may be reading a bit high as many cheap ones do that don't have a zeroing function. What does it read when both probes are touched together? Whatever that is, subtract that.

    That one that ohms in the ballpark. Does the coil rub on that when you carefully push the cone in repeatedly? If something is scraping or it is not moving freely that one can be centered up. You wouldn't necessarily have to remove the dust cap to do that but you need a proper centering jig made from PVC pipe and adjusting screws or a more professional one like @xschop made. I think removing the dust cap is preferable though, to know which way you have to move the pole piece.

    You could remove the dust caps on the other ones with an xacto knife cutting carefully just above the glue line but not too deeply so as to cut the voice coil. Leave an extra margin of safety around the wires so as not to cut into them. You have nothing to lose but those will probably need a voice coil replacement, like xschop said.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • jayward
    jayward Posts: 31
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    i get .5 if i touch the leads... yeah it's a cheap 1... i just try and do things a few times to make sure it's reading right... i have a better 1 but it needs new fuses... and yes, that 1 . look is also what it looks like when not touching anything...
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  • F1nut
    F1nut Posts: 49,804
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    eBay is your friend.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • jayward
    jayward Posts: 31
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    so lets call this 1, the good 1.. lol... it seems to move ok, but feels bottomed out easy if i push in... and i can now see the voice coil is disconnected from the spider, if i push up on it... dhwthd1guqbt.jpg
    5pazszq6btx0.jpg
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  • jayward
    jayward Posts: 31
    edited October 2022
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    little more... the good 1, which may actually be the worst 1(who knows... lol), is the 1 that rattles when shook... if i hold the cone a little it doesn't make that noise though... so maybe it's like that because the spider let go... the others don't make that noise, and can be moved a bit.. i'm thinking maybe the magnets did shift on those 3, now... those are also the 1's with no ohm reading...
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  • jayward
    jayward Posts: 31
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    i'm afraid to put music though it, but maybe the good 1 is fine and just needs the spider reglued... any recommendation of a good glue for that? i also noticed i could use a little glue on the wires that come out from under the dust cap on 1 of my 5jr's... also, how many ohms are these 10's when all put together? from the reading i get at the speaker hook ups on the 5's, those are 4 ohm...
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  • Gardenstater
    Gardenstater Posts: 4,187
    edited October 2022
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    There's a danger that the spider could be distorted too. Looks a little like it is in the photos. If you just glue it up it could be hit or miss regarding whether or not you end up with a cocked voice coil and/or rubbing on the frame piece magnetic pole.

    I actually built a jig to keep the voice coil perpendicular on some drivers that I will eventually repair but you may need to massage that spider back at the same time maybe with a heat gun. @Lawdogg has done this.

    You might want to remove the dust cap to make sure that the bond at the cone hasn't been broken but it is probably just the spider joint. If you do remove the dust cap you could insert some flexible plastic shims between the pole piece and the inside of the voice coil to keep it perpendicular. That assumes that it is relatively centered still and that the pole piece hasn't shifted. Lots of considerations.

    I would try Aleenes Tacky Glue or Super Glue Gel.

    I hope all that damage occurred whilst playing Pink Floyd DSOTM and not Blondie lol.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • jayward
    jayward Posts: 31
    edited October 2022
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    it's a little hard to tell what's going on with it, but upon looking at it further the cone is definitely off the coil... and maybe the spider is also loose in places... i suppose i could try and fix it... this 1 seems pretty tough though... i guess removing the dust cap is the way to go... man, these seem like they are going to need more than i was hoping... i was kinda hoping for a drop in and glue, kit to repair them... i'm not ready to give up on them yet though... i'm ok as long as it was blonde's 1st album...
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  • Gardenstater
    Gardenstater Posts: 4,187
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    Not exactly an easy job for your first attempt at this stuff. :)
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • jayward
    jayward Posts: 31
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    so here's what we're working with... this is the 1 that showed the upper 6 ohm resistance... i haven't taken the others apart at all yet... since i'm assuming those have magnet issues, i need to figure out how to go about getting those off... anyway, this 1 definitely suffers from a destroyed voice coil... looks more like mechanical damage than burnt up...

    blodrg8nwr88.jpg
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  • Gardenstater
    Gardenstater Posts: 4,187
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    Wow! Well we can safely say that this one needs a voicecoilectomy procedure. Bring on the other 3!
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • jayward
    jayward Posts: 31
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    yeah, it definitely got crispy at some point... hard to tell if the magnet shifted... if so, not much, i guess... hard to see through the cone and spider hole... will try and see about the others today... was real curious about the 1 that seemed like it might be good.. but you can also see why it felt like it bottomed out easily... the edge of the vc was bent, and stuck above the magnet pole... thanks for all the help! saw some posts on how to center the magnets, if i need to, and it doesn't seem too bad... just a little worried about trying to get them apart still...

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  • pitdogg2
    pitdogg2 Posts: 24,582
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    That one got a bit too much excursion, probably playing rap! :p
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  • jayward
    jayward Posts: 31
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    damn you, blondie's, rapture!!! ahahahaha
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  • jayward
    jayward Posts: 31
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    so just doing a little cleaning up and putting what i can back together on these... i had to make 2 new gaskets for the tweeters, because i was missing 1... i seem to be missing 20 mounting screws for the speakers... i have no idea what could have happened to those... i had everything in a box together from when i took them apart years ago... still trying to figure out how to take the mids apart... anyway, i've been on a stereo(car and home) kick lately, and trying to get done some doable projects, like these... i also have a pair of acoustic research speakers similar to the 5jr's but with 8" woofers, and a pair of cerwin vega woofers that i just ordered parts for to redo the speaker surrounds... planning on making some high end stereo cables over the holidays, and going through things with my car stereo... i bought a better line output converter and a few small tweaks... anyway, here's a pic of the polks... still got some cleaning to do on them... i also have the grills... the 10's are real nice, and the 5's are getting the wood frames resprayed and new grill cloth(also ordered today)... they had some really bad and dirty white linen grill cloth someone did, when i got them... it was immediately removed... lol...

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