Need help with my "new" Yamaha NS-690II Speakers

[drewk2]

Hello everyone,
I just acquired a pair of Yamaha NS-690II speakers today.

They are in great shape with the exception of one of the dome midranges (and screen cover) is pushed in and the back corner of one of the speakers has a small chunk missing.

Can anyone help with the following?:

--how do you remove the screen over the midrange?
--can the pushed in dome midrange be corrected?
--anyone know how to fix/repair the corner of the speaker? Wood putty?

Any help is appreciated.

 

[tubed]

The screen is held in place by the rubber bushing.
Unscrew the voice coil/diaphragm and carefully push the dome out into shape.
As for the ding, I'd drill out some pilot holes to anchor some "bondo".
Shape and paint/blend to the best of your ability

 

[drewk2]

Thanks for your reply.

I assume that if the midrange screen is held in place with the rubber bushing, you can just use a small flat tip screwdriver to get the rubber bushing out?

If nobody else has any other type suggestions on how to fix the corner of the cabinet, I may get a good friend of mine who is an expert at automotive bodywork to bring some bondo over and get this done...

 

[drewk2]

The screen is held in place by the rubber bushing.
Unscrew the voice coil/diaphragm and carefully push the dome out into shape.
As for the ding, I'd drill out some pilot holes to anchor some "bondo".
Shape and paint/blend to the best of your ability

Sorry to bother, but mind if I ask the proper procedure of removing the screen?

Should you just simply try to get some kind of hooking device and pull on the wire mesh screen, or should you try to remove the rubber bushing first?

If removing the rubber bushing is needed first, how would that be done? It seems as if it is VERY hard and not very pliable.

 

[KenP]

I used a sharp knife to go around the bushing, it's glued in place by the way. Be careful that you don't cut the rubber. The four black screws hold the dome and voice coil in place, it just comes away from the magnet when you take the screws out.

 

[PR Audio]

Bondo works...As for the dome, try pulling it into shape with tape.

 

[drewk2]

It was not easy to get the rubber bushing off. After trying several methods and slightly denting in the outer wire mesh screen where it meets the bushing,
I went around the outer circumference of the rubber with a utility knife and then used a small flat tip screwdriver to pry it out on a spot. Then I got under it and carefully went under the whole circumference. Then I slowly pulled off the rubber bushing.

Then, the screen is still slightly stuck on...it needed pry'd out with the small flat tip screwdriver all around the outside.

After finally getting the screen off, I am glad I just didn't remove the 4 black screws from around the midrange....if I would have, the back of the magnet structure could have just simply fallen off inside of the enclosure and could have damaged the voice coil in the process!
I removed the 4 outer support screws of the midrange frame, removed it from the enclosure, and then placed it on top of a small book I had (the wiring is soldered on the back of the midrange).

Then, with it sitting in a vertical position, I removed the 4 black screws around the midrange and slowly pulled it up out of the magnet.

I was able to get behind the dome with my fingers and was able to push out the worst part of the indentation, but a few of them just simply would not stay out..some smaller indentations just want to pop back in place and not stay out.

Just reverse the process to put back together....and I did not glue the rubber bushing back into place..it is tight enough as it is!

Hope this helps someone.

 

[drewk2]

UPDATE:

Well, after doing all the above steps and being very careful.......my midrange is no longer working.
It was working perfectly fine with the original ugly dent in it before "repairing" it.

I removed and checked all the wiring and visually I see no wires broken or any type of damage.

I even put my receiver on very low volume and hooked up the speaker wires directly onto the midrange terminals and no sound is coming from the midrange.
Sound is backfeeding through and I hear sound coming out of the tweeter and woofer though.

Looks like I may be on the hunt for a reasonably priced replacement midrange.....

 

[onwardjames]

Damn, man. Sorry to hear. My NS690's had MUD in them. I got what I could, said screw the rest. Was afraid I'd have what's happened to you.

Good luck. Those are amazing speakers.

 

[tubed]

Bummer!
The dome was pushed in but not the screen?
Perhaps that midrange somehow got zapped and came close to frying.
The stress may have weakened the voice coil wire and now was time for it to give up.
People have been successful repairing the break in the VC wire if it's break occurs before the former.
Then again there's a nice one for sale on Ebay

 

[sealy]

Use a good-sized ball bearing and roll away

 

[gvalent]

Drewk2,

What a bummer.
Wish I saw your post earlier.
You didn't need to pull off the screen, a total PITA. You didn't need to take off the magnet.
You only had to unscrew the back cap and gently remove the damping material.
With a small paint brush, paint the inside of the dome with a little warm water to loosen up the dome a bit. Then with Q-tip or some such thing push the dents out.
Put the damping material back in and screw back cover back on. Viola!
You can easily fix dented screens without taking them off as well.
BTW where are you located, I may have a pair of mids laying around.

 

[drewk2]

Bummer!
The dome was pushed in but not the screen?
Perhaps that midrange somehow got zapped and came close to frying.
The stress may have weakened the voice coil wire and now was time for it to give up.
People have been successful repairing the break in the VC wire if it's break occurs before the former.
Then again there's a nice one for sale on Ebay

tubed,
Yes, the screen was slightly pushed in also. I am sort of thinking the same thing....the wires were very weak and the movement from me taking it apart just made something give in.
It is very possible that someone can fix it.

 

[drewk2]

Drewk2,

What a bummer.
Wish I saw your post earlier.
You didn't need to pull off the screen, a total PITA. You didn't need to take off the magnet.
You only had to unscrew the back cap and gently remove the damping material.
With a small paint brush, paint the inside of the dome with a little warm water to loosen up the dome a bit. Then with Q-tip or some such thing push the dents out.
Put the damping material back in and screw back cover back on. Viola!
You can easily fix dented screens without taking them off as well.
BTW where are you located, I may have a pair of mids laying around.

WOW....I wish you would have seen my post earlier too!
Yes, now that I know the construction of this midrange, it would me MUCH easier if I would have done as you are saying. If I only had a Time Machine...
I am located near Pittsburgh, PA. and would be interested in you have any midranges available.
Let me know.
Thank you.

 

[bd1886]

Oh heck! (Thankfully those tweets seem to be around.)

Bondo does work but it's bite to the corner's particle board isn't the greatest (and that corner will see a slight bump somewhere down the line).
The best way to deal with that is to use epoxy products found at you local hardware store.

1. Pick away anything loose.
2. Cut back any puckering of veneer (if any).
3. Mask perimeter of damage.
4. With a small brush, apply clear epoxy glue to firm up PB and create a foundation for build epoxy.
5. Use kneading epoxy (comes in small plastic wrapped "logs" located in specialty glue area of store) for repair. Cut off amount needed,smoosh in fine film first to guarantee full adhesion and apply build to corner and smooth to close to exact shape using a wet razor blade.
6. Pull tape and sheer flat to profile w/razor blade when epoxy is 2/3s' set.
7. Touch up fill and sand as needed.

Hope this helps.

 

[KenP]

Same thing happened to me, turned out the wire was broken where it enters the domes surround. I ended up taking the wire out and soldering in another, worked perfectly after that. The wire on the front is kind of strange and just turned to dust when it was touched.

 

[drewk2]

Same thing happened to me, turned out the wire was broken where it enters the domes surround. I ended up taking the wire out and soldering in another, worked perfectly after that. The wire on the front is kind of strange and just turned to dust when it was touched.

Interesting.....where did you cut the wire on each end? That wire is very thin. Looks to be about a #24 wire or thinner.
I would like to give it a try, but not sure if I'm good enough with my solder technique.

 

[KenP]

You'll have to take the mid apart again to check that it is in fact the problem but it most likely is.

On the face plate the wires come out of holes which are filled with a black tar like substance, I first got rid of that with my soldering iron, then I put a small flexible wire through the hole that was left and soldered it the the back of the terminal.

Where the original wire goes into the surround there is a small hole, my new wire went in that small hole and on the back of the surround you should see the voice coil wire, you may have to carefully scrape some of the coating off the the voice coil wire, then solder your new wire to that with just enough heat and don't stay on it too long.

I put a small amound of silicone on the front were the wire goes in and also where it's connected to the terminal.

It worked fine after that, the new wire may be a bit stiffer but it had no effect that I could hear.

 

[drewk2]

Drewk2,

What a bummer.
Wish I saw your post earlier.
You didn't need to pull off the screen, a total PITA. You didn't need to take off the magnet.
You only had to unscrew the back cap and gently remove the damping material.
With a small paint brush, paint the inside of the dome with a little warm water to loosen up the dome a bit. Then with Q-tip or some such thing push the dents out.
Put the damping material back in and screw back cover back on. Viola!
You can easily fix dented screens without taking them off as well.
BTW where are you located, I may have a pair of mids laying around.

Did you happen to check to see of you have any of these midranges available?

Thanks,
Drew