Need help with broken scan speak 2904/7000

[yoke]

I need some advise, help or any thing, regarding broken scan speak 2904/7000

is there any way that I can repair this twitter at home ?
or is it mission impossible, as I have no experience with those things


here's the story

I have those twitters for some time

now I manage to brake one of them.

The thing is that I play them directly to mini aleph
as mini aleph have ''bump'' on power off (I wasn't smart enough to place some capacitor in series or any other protection)
I think that voice coil just ''pop out''

Now this twitter is much quieter than the other, it plays but...

So

I try to contact scan speak
thay didn't answer my emails
(I was hopping that I can send it to them, pay repair and shipping cost...buy they ignore my email)
I found thair facebook web page, I log on,
thay ignore my post

So I try to contact some scan speak distributor (in Canada, as there is no distributor in Croatia)
which respond
but unfortunately thay can't help me, whell they can, but repair would cost more than a new twitter as;
I should send twitter to them,then thay ship it to ss, then ss ship them back, and then they ship it to me !!!
Or I can buy new one from them...

really don't understand why I can send it directly to them...It's not like there is 10000peolple with broken 400Euro worth twitter


any way...
is there any way that I can repair this twiter at home ?


I mean, scan speak wont help me, so I can buy new one or simple try to repair this one
or simple trash it

Any advice is appreciated !!!
thanks

[5th element]

If a standard voice coil/dome replacement assembly isn't available for the tweeter, then there isn't an easy way to repair it.

You could however take a moment to figure out what is actually wrong with the tweeter. I you measure the resistance between the drivers terminals what resistance do you get? According to scan this should measure 3 ohms. If you get anything less then this then it implies that you've damaged the voice coil.

Personally, as the driver is useless as is, I would unscrew the three small screws that flank the dome assembly and remove the faceplate. Depending on how the tweeter is constructed this might release the dome and allow you to remove it and inspect. it. Charred melted or uneven voice windings would be what to look for.

[crazyhub]

Hi,

not the exactly same tweeter but close to it; the photos may help you understanding what is inside...
Scan-Speak D2904/7100 Tweeter

[yoke]

Thanks for replay

I have measure resistance and it's like 3.5Ohm

Then I have resemble front plate by unscrewing three screws

and that was the and, as plug is in the way to remove dome from the rest

I think that plug is glued or something else, it fixed, so it doesn't allow dome to come off... ?
don't know
I think there is not much I can do...?

(it's diferent then the 7100 twetter because of the plug. which wont come off )

here are some pictures

[yoke]

On the pic number 3 and 4 , you can see that I have rise one end from the other, but the plug stays in place, not leting the dome (I think the dome is right name for textile) to come off...

[5th element]

Yes, I was thinking about that before. If you look at Madisound, they've got replacement dome assemblies for the tweeters that dont have a phase plug. Obviously the plug makes it hard to replace the dome.

The thing that puzzles me is the DC resistance being 3.5 ohms. This is perfectly normal, the tweeter has 3 ohms + 0.5 or whatever for the meter/probe/wires inaccuracy. If you had destroyed the voice coil in some way then the DCR would have definitely changed. Of course it is possible that your meter is adding in say 2 ohms of its own resistances and the voice coil is in fact partially damaged. Can you compare the broken tweeter to the one that works with regards to DCR?

I take it the dome is free to move within the gap? It doesn't look like it has become stuck by mistake. Even so a trapped voice coil in a tweeter can usually move at least a little and I'd expect it to produce quite a lot of distorted sound.

[5th element]

Originally Posted by yoke

On the pic number 3 and 4 , you can see that I have rise one end from the other, but the plug stays in place, not leting the dome (I think the dome is right name for textile) to come off...

Indeed I noticed this too. I do wonder what holds the phase plug in place.

[yoke]

Sorry...I forgot to tell this, maybe this explain what I did and maybe that's how I brake it...

one day
I notice that one loudspeaker is playing louder then the other...

so I aproce to the twitter and it look like this



first I taught that I drop it or something like that
but I figure that it was from power off...

I touch the twitter dome and notice that voice coil is misplaced, it was pushed forward...so I gently push it back
twitter have return to his normal visual condition

but it still plays quietly

Now I have measured both tweeters and they both are about the sime at 3.3ohm...
I even connect mp3 player and played some music directly on twitter...the broken one was distorted on bass and quieter then the other...

maybe is just voice coil misplaced or pinched (don't know did I use right word)...but I can't get to her...
maybe it's nothing serious...

[5th element]

If the voice coil was completely displaced then it sounds like something went into the tweeter, overloaded it and caused the coil to leap clean out of the gap. Once out of the gap the coil rested on top of the top plate and hence the driver was stuck.

The alignment for the coil within the gap is incredibly tight and any deformation of the voice coil former will result in a trapped coil within the gap. The silk of the dome will be very strong, as silk is, and also very flexible, I don't think the dome material itself will be damaged, only it might have caused the voice coil former to become bent a little under the stress.

The only way to be sure would be to find a way to remove the phase plug and get the dome completely off the magnet/motor. I don't think you can do a lot with it besides that. I'd be surprised if you could even fix it, this would only be a way of finding out exactly why it isn't working. But if there's a small kink in the former and you can perhaps flatten it out then you might be able to get it going again, providing that removing the phase plug isn't a one way thing.

[5th element]

I'm thinking that the phase plug might either be screwed into place or otherwise glued. You will obviously need to find a way to grip it securely before trying any removal procedure, even if you're careful this is likely to damage the plug at least visually.