Anyone know a fix for this woofer?

[martin1970 361]

 

Overheated voice coil?

Is there a fix for this? 

Does the magnet assembly come apart?

What's that screw for at the end of the assembly do?

 

Not a huge fan of Orevox's price for these things.

$90 last time I checked. 

 

 

 

 

[RichP714 3,163]

The last time we did a group buy (I think we got them for $45) they said theye were going to go up in price due to scarcity.

time to move on to newform research

 

 

[kve777 6,888]

 

 

Overheated voice coil?

Is there a fix for this? 

Does the magnet assembly come apart?

What's that screw for at the end of the assembly do?

 

Looks like a loose magnet. They are usually glued in place. If you ship it to me I should be able to align it, epoxy it and get it going again. PM me.

[mbskeam 1,975]

http://thecarversite.com/yetanotherforum/default.aspx?g=posts&t=3804

 

 reglue???....  been there done this.....

they are still sounding good......

[martin1970 361]

For some reason,

I thought it would be a good idea to see if the scraping was

on the in stroke or the out stroke of the woofer piston.

 

Being the genius that I am, I loaded up Audio Test Bench and

proceeded to send 20 Hz to the woofers.

 

"Boy, isn't this fun, let's do 10 Hz." 

 

"Hey 5 Hz looks cool, I can almost tell when they're scraping."

 

"Hmmm, nothing at 1 Hz, let's try 1.5 Hz. Cool, it scrapes on the way out."

 

"Hey, what's that smell? Oh shit! varnish! fuckfuckfuck!" 

 

running for the power switch..... 

 

So now it's time to let things cool off and perhaps take up nail biting again...

 

And perhaps switch to a smaller fuse. 

 

EDIT: Turns out the smell is coming from the other channel,

which, thankfully, seems to be firing on all 4 cylinders.

 

[martin1970 361]

@mike&kev: 

All 8 woofers seem to have uneven stacks of magnets,

But not one magnet would move when twisted pushed or pulled.

There is also quite a bit of glue visible on all of the magnet stacks.

Can these still be aligned? 

 

@mike: Very cool thread. Not sure how I missed that. Wrong search terms I guess.

Did you make that tool yourself?

Were all of the magnets that you reglued already free to begin with? 

Do you have a method for breaking them free without destroying the voice coil?

 

@Rich: Those look really interesting but I'm afraid they may be beyond my budget.

 

@all: What's up with the screw on the back of the magnet stack?

Is the hole for some kind of puller? 

[oldtexasdog 2,456]

I don't know if this will help but there is a place in Dallas called Freeman Tule speaker repair that has been in business ever since I can remember-50 years or so. They repair any speaker you can imagine-home or professional. Old School and I don't think they even have a web site-214-324-1132. They have always been friendly and free with information in my experience.

[Guest RodH]

Question for you experts:

 

The Newform/Dynavox WP1220 Paper Carver replacements - 16ohm.... there are 4 in an ALS original - what's in my Silvers (there are only 3) same unit or not? I am thinking of archiving 6 spares for future considerations...

 

Thanks

 

RodH

[mbskeam 1,975]

@mike: Very cool thread. Not sure how I missed that. Wrong search terms I guess.

Did you make that tool yourself?

Were all of the magnets that you reglued already free to begin with? 

Do you have a method for breaking them free without destroying the voice coil?

yes I made this tool on my old lathe.....

yes the mags come undone during shipping....

the glue they use on these sucks, too rubbery for the app, it scraped right off the steel and magnets and not enough also.

did some research, found a few very good epoxy's, but these may not have held up as well to the vibrations.

the super glue I used is loctite brand ultra gel....

it has set time that allows the magnet to be set in the proper position......

also my research showed  this type of glue has a bit of rubber like flex to it, for vibration.....

plus when I used it to stick 2 pieces of steel, these held up to the point that it would bend the material before it let go.

when the scrap test was done, it was harder to scrap off the steel than the stuff they use on the replacement woofers.....

no, I just pulled straight up on them when I went to reattach them, the magnetic bond is not too strong, any more and the VC's most likely would have needed a diffrent tool to reattach them

[weitrhino 1,443]

Not the same in the silvers.  The Originals had the honeycomb 4 ohm woofs, the Silvers and Plats had the 16 ohm cones.   

 

http://www.dynavox.com/index.php?cPath=31_67 

[Guest RodH]

Oops - I meant the Plats. Look to be the same - has anyone bought these units?

 

I've been trying to figure out why there is a 1 ohm resistor in series with the gang of 3 parallel wired bass units in the OEM crossover.

 

 The 3 units would present a 5.33 ohm load, adding 1 would bring the number to 6.33 - I guess that and the effects of the rest of the crossover to total reactance is close enough to the "nominal 8 Ohms" in the manual comes from.

 

I'm going to look into the crossover frequency change difference leaving that resistor out of my crossovers will make and might just adjust accordingly.

[martin1970 361]

Not sure if I asked this clearly or not:

 

Anyone know how to detach the magnets without destroying the voice coil?

 

I have 2 extra damaged woofers to practice on before I take on the one from the video. 

 

 

[Guest RodH]

There is a thread here somewhere posted by mbskeam with pictures of how he made a magent repair.

 

[martin1970 361]

I've read that thread and it's really helpful for reassembly.

 

Call me stupid, but I can't figure out how to get them apart.

 

 

 

[Guest RodH]

PM Mike (mbskeam) - he should have some ideas. He's usually a very helpful guy.

[kve777 6,888]

I've been successful by screwing the speaker down on a workbench or table to keep it stable and prying up at two or three points around the seam where the magnet meets the basket with hard, sharp plastic, like ice scrapers. Apply even pressure to lever it upwards to clear the voice coil. Sometimes I have to do it a little at a time, shimming the gap with plastic or wood. Avoid screwdrivers or anything steel to pry or shim with, as the magnetic attraction complicates things. I'd like to hear Mike's method.

[mbskeam 1,975]

strong hands......

the magnetic pull on these is not that strong. you should be able to pull straight up, if its fully busted free.

if not, rotate the magnet to full free, then pull up, the 1st  3/4" to 1" up/down is the danger zone

[martin1970 361]

Thanks for all the great suggestions.

 

Tried the scrapers.

Then graduated to prying on opposite sides with 2 big screwdrivers with tips covered in plastic.

All that seemed to do was make the metal frame flex. 

 

Tried twisting. Even tried one of those jar opener lever things.

Might borrow a strap wrench from one of the pipefitters at work. 

 

Looks like the glue is still pretty damned healthy.

 

I'm still wondering about the hole in the end:

 

Anyone know what it's for?

Puller?

Alignment during assembly perhaps?

 

Here's more info about it:

I tried threading a longer screw in as the thread seemed like it went all the way to the bottom.

However either it didn't or there's 2 pieces that aren't fully aligned...

 

The space between the red line and the yellow line is the hole depth.

Yellow being the bottom of the hole, red being flush with the surface.

 

On top is the original screw.

The middle shows how far I was able to thread a longer screw before it stopped. 

The bottom piece shows the full depth of the hole. 

 

If I owned a rubber hammer,

I probably would have knocked the crap out of this thing in frustration.

 

Any more suggestions? 

[Guest RodH]

If you are able to borrow a strap wrench, any chance you could borrow a bearing puller? That might do the trick.

[kve777 6,888]

 

 

 

I'm still wondering about the hole in the end:

 

Anyone know what it's for?

Puller?

Alignment during assembly perhaps?

 

Here's more info about it:

I tried threading a longer screw in as the thread seemed like it went all the way to the bottom.

However either it didn't or there's 2 pieces that aren't fully aligned...

 

The space between the red line and the yellow line is the hole depth.

Yellow being the bottom of the hole, red being flush with the surface.

 

On top is the original screw.

The middle shows how far I was able to thread a longer screw before it stopped. 

The bottom piece shows the full depth of the hole. 

 

If I owned a rubber hammer,

I probably would have knocked the crap out of this thing in frustration.

 

Any more suggestions? 

I think it holds a slug inside the voice coil, probably to center it while the glue sets.

[Jim Coash 126]

In my experience, voice coil rubs are more often than not the result of a warped voice coil due to overheating from clipping.  If the speaker was dropped, then it is possible the magnet alignment is off.  Before I attempted a re-alignment I would have a qualified re-cone company have a look.  This is always superior to replacing drivers but it should be done in pairs to retain a mirror image match between speakers.  I have had little success re-aligning a magnet structure to original tolerances in any case. Too often I have come across really good speakers that have been bastardized.  The worst was a pair of McIntosh ML-4 speakers where the original woofers had lost their foam and been replaced by generic woofers.  The owner's kids had "fixed" them for the owner and thrown the originals away.  Huge mistake.  He wanted big bucks for them.  I told him they were worthless unless he still had the original drivers. Part out the original elements and chop up the cabinets for kindling.  If only he had re-coned the originals. They would have been worth a lot then.  I bought 6 E/V-15B woofers on eBay for .99 cents each plus shipping.  All were destroyed by being driven by an amp insufficient in power for the task at hand.  It cost me about $70/each to have them completely re-done as the latest E/V-15G speakers with the finest parts available.  They now are in my guitar amps and sound incredible.  Stevie Ray and Joe Bonnamassa use(d) only E/V in their amps (many other great players too). I still have one pair left for a future project.  I do not believe there is a better speaker unless it is the E/V-12G or JBL D-130/140 series speakers now supplanted by the E-Series which are supposed to be even better.  So far, I have never had the chance to see or hear those.  I sure am sorry I sold the pair of D-130F JBLs I owned in the 60s.  Jim