Let's Try to Fix a MW6511 Damaged in Shipping...

[Saftgeek]

I'm going to try my hand at repairing a MW6511. I recently bought a set of SDA-1c's and the right speaker ended up having a blown driver. After looking into a replacement, I was disappointed to find out the new replacements aren't held in the same light as the older ones. After posting my trials and tribulations on CP, I lucked out when a fellow CP member dug one out of storage and sent it to me. Even though he went the extra mile by packing the unit in tons of bubble wrap, the apes at UPS managed to break the magnet loose and bend the driver cage.


The driver was making a scratching noise at lower volume. Further investigation revealed the magnet had indeed shifted. I went to work trying to find anything I could about repairing this type of damage. I read and re-read a posts on how to re-attach magnets. One very good thread suggested using 3 screwdrivers and slowly pry apart each side of the magnet. I followed this person's lead and used shims to help separate the magnet from the basket. I really had to work to get them separated. Once apart, I could easily see where the epoxy had become brittle over all the years this speaker has been awaiting it purpose.


The other side of the magnet was still attached, but I figured if I'm going to take the time to attempt a repair I might as well do the entire thing. I used a dead-blow hammer to break this apart. I then pushed the cone forward and covered the voice coil with tape. I don't want to get anything in the space, as that would render the entire project useless at that point.


Once the voice coil was covered, I scraped away all the old epoxy. It was stuck on really well and took quite a bit of effort to remove. I used the same blue tape to remove all the little pieces then wiped the entire thing down with alcohol. I paid close attention to the piece which guided the voice coil. I cleaned it thoroughly and made sure to wipe it with alcohol as well.




Once the magnets, basket, and the rear piece were scraped and wiped down with alcohol I used some JB weld to re-attach the magnet to the rear piece. I made certain to not use too much where it may seep back and interfere with the movement of the voice coil.






I am done for tonight. I cannot do any more work until the JB Weld sets up. I did go ahead and make a jig to help set the magnet so there's no interference and the voice coil doesn't rub. I'm hoping to make it to the end of this adventure without messing anything up. If anyone has suggestions or some advice, I will gladly accept it. I can provide my contact info for anyone who would like to speak rather than do this back and forth on a message board. PM me and I'll do my best to accommodate your schedule.

Thanks for the inspiration... One way or the other I will get these SDA's back in play!!!

-Saftgeek

[Saftgeek]

Okay... I had some extra time so I wanted to post the jig that I made to hopefully tweak the magnet in place so the voice coil doesn't rub. I went to Lowes and purchased a 4" pvc coupling, JB Weld, some 1/4" x 20 bolts and some superglue. After I got the first part of the speaker glued together I took a rough measurement to see where I needed to drill holes in order to secure the jig to the basket. I drilled 4 holes in the very bottom of the coupling and tapped them 1/4" x 20.




After placing 4 bolts into the jig I secured it to the speaker frame and measured where I needed to drill the holes which will be used to position the magnet so that it doesn't rub (hopefully). I drilled 6 holes and tapped them for the same size. The following two pictures show the jig mounted to the speaker frame and the other screws mounted so I can adjust the position of the magnet.






I will attempt to mount the magnet and adjust the position tomorrow night, hopefully.

I have a question for anybody who has attempted this repair before. On the other posts it shows the dust cap being cut and shims used. Is that totally necessary? Can I position the magnet without removing the dust cap? I am very nervous about cutting the cap out. I'm also not sure what type of glue to use to glue the dust cap back into place. Most repairs on the web are for large subwoofers and aren't really as delicate as this one. Suggestions or advice would be greatly appreciated...

-Saftgeek

[Saftgeek]

Sorry folks... I double-posted. Still a nub here.

-Saftgeek...

[PolkieMan]

Wow I saw the speaker frame, they beat the crap outta it! At first I was thinking that if you could straighten the frame maybe it would realign the magnet. But looks like it was worse than first thought. I don't know about the dustcover but superglue on a wooden toothpick might work

[nspindel]

I can tell you this much. Not sure who told you the replacement (new) drivers aren't held in high regard. I needed drivers for my CRS+ rebuilds (the same 6510's and 6511's as in the 1C's) and they sound fantastic. I made inquiries at the point where I was deciding whether or not to buy the new drivers, and every answer I got was that the new ones are great.

[Saftgeek]

Mr. Spin - all my info comes from this board and AK. I think the main objection is because they don't physically have the same appearance. I have not heard one, therefore I cannot say with certainty. Since you have, I am very glad you posted. I feel a little better about the what-if scenarios that may arise.

I am still hoping someone can post and provide some guidance on whether or not I have to remove the dust cap. I would love to bypass that step if I can...

Saftgeek-

[heiney9]

Physical apperance has nothing to do with performance. I have never heard any bad things about the current replacement drivers. I also put little to no stock in most of what is discussed on AK. Their focus is much different than the majority of the things we focus on here.

Many over there think a 70's Sansui reciever running Cerwin Vega's with an EQ in the path configured in a classic "V" shape is about the best thing going. That was cool when I was a teenager, but not now.......it sounds horrid.

Of course there are some people over there that value great sound, but few and far between in my experience. I still visit and read the board, but I don't bother interacting since most of it is sillyness.

My point is if you can't fix the one you have properly, a replacement from Polk would be just as good.

H9

[brgman]

Sh!tcan the damaged driver and get a new one.
Consider time, money, and the fact it may still not be right.
Is it all worth 50 bucks?
If you want to toy with fixing it for a spare later then have at it.
Are the speakers sitting idle while all this is going on?

[heiney9]

^^ What he said! I was going to say something similar, but decided to use a softer approach, but the above is the solution.

yes, the speakers have been idle

H9

[gdb]

Do what you want, when you want, and, at your own chosen speed.

[michaeljhsda2]

I can tell you this much. Not sure who told you the replacement (new) drivers aren't held in high regard. I needed drivers for my CRS+ rebuilds (the same 6510's and 6511's as in the 1C's) and they sound fantastic. I made inquiries at the point where I was deciding whether or not to buy the new drivers, and every answer I got was that the new ones are great.

+1. I bought a new 6511 for my 1C's and it sounds good.

[naturallight]

I'd be interested to know ..When you bought it....and how loud do you play your 1C's???? As i play mine..on the loud side..LOL

Sounds, good..is not..yeah it sounds as great as the old one...Just saying..

[Mike Reeter]

I think I would have filed a claim with UPS before I would have taken the damaged driver completely apart, a replacement from Polk would work just fine. I've purchased a couple of mid drivers and several RDO tweeters over the years, no problems what so ever.

[michaeljhsda2]

I'd be interested to know ..When you bought it....and how loud do you play your 1C's???? As i play mine..on the loud side..LOL

Sounds, good..is not..yeah it sounds as great as the old one...Just saying..

I bought it 2 years ago. It plays loud and sounds good, no issues. I also have a pair of 1.2 TL's where the previous owner put a 6511 replacement in it. The 1.2 TL's play a lot louder than the 1C's and the driver performs just as well as the originals. Not better, not worse.

[nspindel]

Not better, not worse.

As a replacement should....

When my CRS+'s are done, I believe the only parts that will remain original are the cabinets (minus the veneer), the passive radiator, the internal wires, the polyfill, and the binding post cup (with all posts replaced). Everything else - RD-0198 tweeters, 6510 and 6511 drivers, crossover boards, all crossover components including inductors, the large 16mH inductor, and the binding posts (including the SDA connection) will all be new.

[Saftgeek]

I totally get the time/idle aspect. What I'm trying to do is challenge myself a little and salvage rather than discard. I like the idea of having a spare. Since this is going to be part of a HTS these speakers will get used at all levels. I have re-connected my Infinity speakers in the interim.

I will make my attempt at mounting the back plate tonight. I've sent a couple PM's to folks who've successfully repaired in the past. Hopefully I'll hear from them and have enough time to finish the job.

Thanks again for the posts... BTW my jeep radio is still configured in the classic V... Never grow old!

-Saftgeek

[naturallight]

The only reason i ask about the timeframe. I bought a 6511 must be well over 5 years+...worked perfectly. I bought another 6511 that was maybe some place around 2 years...but thats a guess. Did NOT work so well....It would pop if you played it too loud. Changed the driver to the other speaker cab, to see if there was something wrong with that X over..did the same thing in the other speaker cab. Polk sent me another driver...did the same thing...so i just put the 1C's in the back room at that point.

Now maybe....they had a bunch of bad drivers at that time. Hell there all made in China..so who knows. I was going to wait to find an original 6511...but may give Polk another shot, see what happens...at most, i just have to send it back.

I'm not saying there bad..but the ones i got(at that time)...you really can't go past 11:30..on the volume..dependent on source CD.

[mesquitehead]

Had the new replacements and sent them back, did not sound the same to me and one of the surrounds came unglued as well. A certain person at Polk agreed with me that the new ones were not up to snuff with the old ones. And, I play my music LOUD! Just my experience and my 2 cents worth. Good luck with the repair!

[transmaster]

Physical appearance has nothing to do with performance. I have never heard any bad things about the current replacement drivers. I also put little to no stock in most of what is discussed on AK. My point is if you can't fix the one you have properly, a replacement from Polk would be just as good. H9

I can vouch for this statement. I had to purchase a pair of MW-6503 from Polk to replace an original pair in a Monitor 10B (purchased new in 1989) that where burnt up. Comparing the speakers one with a set of the originals and the other with the new drivers I can report to you I cannot tell the difference. The only visual difference is the wiring coming from the voice coil in directly attached to the external connectors, and not first attached to the speaker cone. Don't hesitate to purchase a replacement set from Polk, with your Polk Audio Club discount that is $48 dollars each with free shipping. This morning I ordered a pair of RDO-194 tweeters (also $48 dollars each and free shipping) to replace the original SL-2000's one of which has failed after 20 plus years of use. Talking with the Polk parts guy he told me not only do they sound better but they are constructed much better then the SL series tweeters. Mean while over at Audio Karma I am assured the RDO-194 is the biggest tweeter turd made on this planet, that I should go out and find another 20 year old SL-2000, ya right... When I pointed out how the RDO-194 is regarded on the Polk Audio forum, I felt like the lone cowboy in a saloon fight scene from an old western movie where he is set upon, beat to a pulp, and summarily thrown out through the front door onto the street with a bunch of scroungy grub stake riders laughing at me.

[mesquitehead]

Some people are cool with car engine blocks made of aluminum and iron sleeved cylinders, I'l stick with a Chevy 350 4 bolt main and an iron block all day long. Call me old fashioned. To each his own.

[Saftgeek]

Update... I got my arse kicked on this one. I tried my best but the basket is bent and that positions the voice coil at a slight cant. This means no matter how hard I try the voice coil will rub. I am going to have at least three Crown and 7ups tonight to console my battered and bruised ego. Like it or not, tomorrow I will be ordering a new 6511 replacement...

-Saftgeek

[mesquitehead]

Update... I got my arse kicked on this one. I tried my best but the basket is bent and that positions the voice coil at a slight cant. This means no matter how hard I try the voice coil will rub. I am going to have at least three Crown and 7ups tonight to console my battered and bruised ego. Like it or not, tomorrow I will be ordering a new 6511 replacement...

-Saftgeek

Might try screwing a couple pieces of 2x4 together with some 1/2" piece of wood shims in the center then slide the edge of the basket in there and gently bend it back into shape.

[Mystery]

Update... I got my arse kicked on this one. I tried my best but the basket is bent and that positions the voice coil at a slight cant. This means no matter how hard I try the voice coil will rub. I am going to have at least three Crown and 7ups tonight to console my battered and bruised ego. Like it or not, tomorrow I will be ordering a new 6511 replacement...

-Saftgeek

Hmmm... I was assuming you straightened the basket before repair.
Even if the magnet shift is fixed, how does the bent basket fit in the speaker baffle?

[littlewoodboats]

I would think the first order of business would be to straighten the basket.

[transmaster]

If a good replacement is available there is no sense in messing with something this badly damaged.

[Toolfan66]

It would have never worked anyway, that pin would have never been parallel to the magnet with JB weld smeared on that plate let alone it being parallel to the voice coil..

[11tsteve]

has this been documented with pictures and an insurance claim filed with UPS?

[mesquitehead]

I would think the first order of business would be to straighten the basket.

That is my thinking, nothing else is going to work till the basket is straight.

[Saftgeek]

I will try your idea with the 2x4's. I'm not sure I can put that much torque on it. This thing is so frustrating. As for it not being parallel... You don't know what you're talking about. The layer of JB Weld is so thin and the magnet is super-strong. It put even pressure on the face. The problem is not the plate, it's the basket. I will give it another shot and see how I fare... Since I walked away and took a break I am ready to try again.

As far as not straightening the basket before securing the driver. There was no way to know how bad the driver was until you first re-glued the thing and tried it. It really doesn't look that bad but there is zero tolerance around the voice coil.

I'd say wish me luck but from the tone of many of the posts here I'm thinking some of you prefer to watch the crash...

-Saftgeek

[brgman]

I'd take the 2x4 and use it like a bat and knock that thing to the trash can.