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NS1000 Woofer magnet shift

S

srinath

Super Member
I have the dreaded magnet shift, and I pried it off and it was pretty much out easy, it was stuck by magnetism, and not every much else.

From here on I need to remove the cone and VC and spider etc right ? And reglue it back like it was a refoam job ?

Cant I get it aligned right with the magnet ?

Thanks.
Srinath.
 

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I just remove the dust cap, leaving a bit still attached, shim the voice coil back to center, and glue around the magnet with a healthy amount fast dry epoxy.
Reattach the dust cap and enjoy.
 
Oh wow, cool I actually figured I can eyeball and measure align it from the back and sit the magnet on top of the thing with plastic clothes pin tails - tapered wedges and non magnetic - sort of like the polk audio youtube video but he has a complicated idea of centering it mechanically instead of electrical/magnetic and eyeball … BTW The VC is 2.75", the OD of the hole is 3"+ and the ID is just about 2.5" on the magnets, its easy to align with 1/4" radius difference.
I can remove dustcap too, I have the same paper dustcap types sitting round here - even if I lose the dust cap, I can replace it. Yea dustcap will get me a eyeball alignment a lot better and still can use plastic clothespin tails to keep the magnet off a bit so I can slide it if needed.

Will do to the "working" woofer as well, once I do this one right. may just open a bit, shoot in glue and let it glue back down. And JB weld the outside.

Thanks.
Srinath.
 
Dustcap removed, but the center pole to ID of VC former is very very tight. I'll figure out something to get it aligned up right.
Thanks.
Srinath.
 
srinath said:
Dustcap removed, but the center pole to ID of VC former is very very tight. I'll figure out something to get it aligned up right.
Thanks.
Srinath.
Click to expand...
I've never removed the magnet and never have attempted replacing a magnet back onto the basket assembly.
I'd worry about a sudden magnet movement and V/C damage, perhaps not perhaps it can be done with care.
Some AK'ers such as "damage" builds a nice jig for this purpose.
Don't touch the working woofer;)
 
avionic said:
I have a 690 with this issue..
Click to expand...
Hey Ft. Dodge
My repair is "quick, down and dirty"
Remove the dust cap but leave a tab so the cap is dangling, makes it easy to reattach.
Place the woofer magnet into a table vice clamp, secure just enough and drive the basket like a bus steering wheel thus with a bit of muscle gradually open the VC gap and drop in shims of choice to even out the gap.
Remove the woofer from the vice with shims still holding the gap tight and quick epoxy the snot out of the magnet assembly.
Reglue the carefully cut dustcap(with a little tab left connected to the cone, watch those VC wire leads when cutting).
Might work for you.
 
tubed said:
Reglue the carefully cut dustcap(with a little tab left connected to the cone, watch those VC wire leads when cutting).
Click to expand...
img-3518_orig.jpg
 
Oh I will. Once I get some other higher priority jobs done.
 
I have a secondary problem as well here. The VC looks nice and intact and not burnt/broken. But I cant get a steady ohm reading out of it. On a known good woofer after the meter wanders a bit it does get to a steady 3.8 (4 ohm) - I cant see why it would be burnt, but I also don't see why it shouldn't be steady either.

So VC's for these are unobtainium ?

And I have it all nicely eyeballed out and ready to fit etc etc lined up but its still pinching and grinding, I don't think my vice skills are on par with you Tubed.

Anyway some cool pics.

Hey there is another kind of Yamaha in the background in one of the pics. It too makes a lot of bass. LOL. I would use it instead, but it weighs like 500 lb and its got way more power.

Cool.
Srinath.
 

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Eagerly awaiting my VC's, but in the meantime imagining a rig to align these, one that will accept a slow curing epoxy in the middle.
I have come up with a steel channel about 1/2" wider than the widest point of the magnet - that's 6" - channel could be even wider, 7" or 8" even with a bolt hole and a nut welded on the inside where if you install a bolt, you would push the plate that's attached to the basket only. So the process would be, put the 90 minute or whatever time epoxy, put the basket over the cone, lining up the VC as well as you can, and pinch or not, put them together. Then use the bolt to push it to where it wont rub and grind the VC.
I'm replacing the VC after doing this but I need to get it to not rub in the first place, I can take up a bit of lopsided fit up when I glue the VC I guess, but I'd rather make a rig to get it spot on. Then let it cure, then replace the VC.
Cool.
Srinath.
 
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