Frozen 6511 in SDA 1C's

dcmartinpc

OK, so I just found a frozen 6511 in my SDA 1C's. AHHHHHHH!!! It was fine yesterday. Anyways... looking for some direction. I see 3 options.

1.) Locating a used 6511 from someone that matches.

2.) Try and unfreeze the driver, but I would not know where to start and how in the world to perform this. I have seen the jig, but have NO idea how it works.

3.) Get a replacement driver from Polk. From what I can tell, Polk has 6511 replacement drivers, but they lack the shiny coating. Are they exactly the same otherwise?

Please help... I am sitting here depressed with my 2 week new to me SDA 1C's...

Don

AudioGenics

my suggestion would be to order a factory replacement driver directly from Polk Customer Service (if available)

You are assured of getting a new genuine driver and with factory support.
The driver may not be exactly the same in appearance however you know that
the factory 6511 replacement will be 100% compatible.

Customer Service & Tech Support:
polkcs@polkaudio.com
1-800-377-POLK (7655)
9AM-5:30PM EST Mon-Fri
(410) 764-5470 FAX
International +1-410-358-3600

Polkersince85

Check the magnet on the driver as it may have shifted. There are ways to repair if it did shift.

.

dcmartinpc

The magnet (The black center piece) is definitely loose/has shifted. I pulled the driver out and the magnet actually moves on the back plate and it accidentally turned it. I wasn't meaning too, I was just trying to shift the magnet. Would that have damaged the voice coil? That would line up with option 2, correct... I would need to use the jig to line it back up, the problem is I am not sure exactly how to proceed in that situation.

Also, if I buy new 6511 drivers, should I order 4 of them to replace all of them in my 1C's. Should I also order 6510's so they all match?

Thanks!

Don

AudioGenics

check this thread out
if you want to try

http://www.polkaudio.com/forums/showthread.php?t=102923

http://www.audiokarma.org/forums/showthread.php?t=130808

zarrdoss

from my understanding Polk has no new 6511's I don't know if they are going to get anymore.

dcmartinpc

zarrdoss wrote: »

from my understanding Polk has no new 6511's I don't know if they are going to get anymore.

AHHHH!!! Are you kidding!!! I will call them on Monday. Maybe I will get lucky.... :eek: I am so upset, the magnet must have shifted... It is weird because the magnet is spinning but it doesn't come apart.... A little odd...

I looked at the threads and I am still a little confused as to how it all works... I will try to do some more digging, but I might be up a creek.

This would SUCK!!! I have only had these speakers for 2 weeks


Don

AudioGenics

Only 2 weeks... that is a bummer
sorry to hear about that

It is an easy repair once you get a replacement.

If the voice coil spacing has not shifted
I have read that JB weld will affix the magnet
and some apply it as a precautionary measure.

http://www.polkaudio.com/forums/showthread.php?t=97719&highlight=weld&page=2

http://www.polkaudio.com/forums/showthread.php?t=98202&highlight=weld

dcmartinpc

I am confused on how to check all that though. The magnet spins, which is weird. I thought that the back plate was epoxied to the magnet, then the magnet to the speaker. Can someone explain this to me a little more in detail? Do I just pry between the magnet and the basket to pull it apart? Can i realign it without pulling the magnet off?

Thanks!

Don

zarrdoss

the magnet will not come apart because the magnet is holding the two metal plates together, the back plate has the pole on it, when the glue holding it together fails the magnetic field pulls the pole to the front plate and pinches the vc in the process thus freezing it up. thats why you need a jig to hold the correct VC gap while the new epoxy dries. its a good ides to epoxy around the edges of the magnets of your unfrozen drivers for insurance.

dcmartinpc

OK. I just pulled the magnet off the basket by hand..... The back plate/pole piece (Am I identifying these correctly) are still epoxied together. I am assuming that is a good thing So I think I understand this jig a little better now. Get the cone suspended with the pencils, squeeze the magnet in the pipe, then use the screws to center the basket/voice coil on the pole. I guess I could even test it while in the pipe. Then epoxy everything back together, once it all works, right?

Don

zarrdoss

you are working with a powerful magnetic field, or against one.

dcmartinpc

I now understand the epoxy I have seen on the other drivers Things are making a little more sense. I think I will try to re epoxy this thing... I might still buy some 6511's if someone has them!

What epoxy would be best to use between the magnets and the plate?

Thanks!

Don

Toolfan66

zarrdoss wrote: »

the magnet will not come apart because the magnet is holding the two metal plates together, the back plate has the pole on it, when the glue holding it together fails the magnetic field pulls the pole to the front plate and pinches the vc in the process thus freezing it up. thats why you need a jig to hold the correct VC gap while the new epoxy dries. its a good ides to epoxy around the edges of the magnets of your unfrozen drivers for insurance.

Agreed!!! I JB weld all my drivers even my spares have been JB welded..

Good Luck!!! they do show up now and then.. Keep your eye out on ebay as well..

dcmartinpc

Also, can I fix this thing without removing the dust cap?

Don

Toolfan66

dcmartinpc wrote: »

I now understand the epoxy I have seen on the other drivers Things are making a little more sense. I think I will try to re epoxy this thing... I might still buy some 6511's if someone has them!

What epoxy would be best to use between the magnets and the plate?

Thanks!

Don

Having spares is a good idea as well...

AudioGenics

If you get an image off the internet of a speaker that is a cutway
that will give you an idea of how it should be put together

essentially you are realigning the voice coil, pole piece, and magnet
There is that spacing or air gap that allows the paper or whatever material cone
to freely move.

I attached one such example

I hope it helps you.

zarrdoss

dcmartinpc wrote: »

Also, can I fix this thing without removing the dust cap?

Don

its possible but very difficult, its essential to have the same gap between the pole and the front plate all the way around, pulling the dust cap is the only real way to ensure you have the same an equal gap. if you carefully cut it with a x-acto knife where the dust cap and cone meet you can glue it back with black craft glue and no one will ever notice.

dcmartinpc

Now that I pulled it apart it all makes sense I now get why the jig is needed... I neglected the whole magnetic force pulling the pole over to the plate on the speaker and causing it to pinch the voice coil. The pole is still attached to the magnet, so I will epoxy that around the edges to keep it there.

Can I do this without removing the dust cap? I just don't feel comfortable removing it since it is metal mesh, and I wouldn't know the first step on how to reglue it back on. Can I just pull the cone up with the pencils and rubber bands, then set the basket into the jig. Once it is the jig, finger tighten all the screws. Then remove the pencils holding the cone. It should drop slightly, but I would guess not all the way until the screws are adjusted so the voice coil will fall in over the pole for lack of a better term. If the speaker moves cleanly, I am assuming it is good.

Any suggestions on epoxy? How much to I apply, I obviously don't want to epoxy the voice coil to the pole

Also, Do I need to put pressure on the basket to make it seat well with the magnet. Or is it just sitting there enough?

Any other advice is MUCH appreciated.

From what I understand, the screws only provide very slight adjustment to get the voice coil centered.

Just saw your post zarrdoss. How difficult is it to cut the metal mesh used on these drivers? Black craft glue should be readily available, I would think...



Don

Toolfan66

zarrdoss wrote: »

its possible but very difficult, its essential to have the same gap between the pole and the front plate all the way around, pulling the dust cap is the only real way to ensure you have the same an equal gap. if you carefully cut it with a x-acto knife where the dust cap and cone meet you can glue it back with black craft glue and no one will ever notice.

Have you done that? Where do you get the glue?

AudioGenics

Usually you do not need to "go thru the topside"

I cut the dustcap if I were changing a crushed or pushed in dustcap
happened alot with little kids discovering what things were.

Not sure what else removing the dustcap would be useful for
basically it is just to keep dust out of the voicecoil and gap.....

dcmartinpc

Was my description of what to do as far as seating the coil on the pole correct? Keep it held up, set the speaker in the jig on the magnet. Remove the pencils and then adjust until the voice coil settles down into the gap?


Thanks!

Don

AudioGenics

http://www.audiokarma.org/forums/showthread.php?t=130808

the poster states "...The Pencils and rubber bands allow the cone and coil to go as far forward as possible. This allows you to lower the magnet into the front plate....."

dcmartinpc

AudioGenics wrote: »

http://www.audiokarma.org/forums/showthread.php?t=130808

the poster states "...The Pencils and rubber bands allow the cone and coil to go as far forward as possible. This allows you to lower the magnet into the front plate....."

OK. Somehow missed that part :eek: I will have to give this a try. It is my best option at this point, unless I can find one...

If anyone has any other options, opinions, or ideas, keep em coming!

Thanks!

Don

gimpod

AudioGenics wrote: »

Usually you do not need to "go thru the topside"

I cut the dustcap if I were changing a crushed or pushed in dustcap
happened alot with little kids discovering what things were.

Not sure what else removing the dustcap would be useful for
basically it is just to keep dust out of the voicecoil and gap.....

The whole point of cutting the dust cap is to make sure you have even spacing all the way around the voice coil and plug and to get the voice coil centered before you lower it down. BTW don't forget to check the voice coil, on an 6511 it should read around 4 Ohms if it reads infinity it's toast toss it and start looking for a replacement.

nooshinjohn

I will check my stash when I get home... I may have one.

AudioGenics

gimpod wrote: »

The whole point of cutting the dust cap is to make sure you have even spacing....

my thoughts was to use the jig to hold the magnet in a stable position
and try an alignment without removing the dustcap
as the basket is slowly lowered into the pole piece and
if the cone freely moves he probably will be OK.

zarrdoss

TOOLFORLIFEFAN wrote: »

Have you done that? Where do you get the glue?

I have done that on an old pair of woofers, un-froze them. I have replaced the dust-cap on several Polk MW though because of severe push in, you can get black glue at a craft store or put food coloring or a few drops of rit black fabric dye in reg Elmer's glue. I used good dust caps from bad drivers.

nooshinjohn

I checked my stash... three 6510's and a 6501. Sorry man, but I will keep my eyes out for you.

[Deleted User]

Another thing to consider is if the voice coil has rubbed the metal staking ring on top of the magnet for any amount of time it may have caused some of the voice coil coating to have been rubbed away. This can cause a short at some point in the future. I have seen this happen, real hard to detect as well. As for repair, I would go down through the dust cap. Be very careful when cutting the dust cap away. A shim should be placed around the voice coil while gluing the structure back together to maintain consistent spacing within the gap. I am not sure what thickness the shim is, if you are interested I can get this info from my bud who works at Polk who does all the drivers and tweeters. Let me know. :cool:

dcmartinpc

The gap would be nice to know. If I do this, I would like to get it back to as close to spec as possible.

John, I might take one or two of those 6510's just to have some around if you would be willing to sell some. I would appreciate you watching out for some 6511's... I would REALLY like to replace this one, then fix this one to have as a backup.

Thanks everyone,

Don