Overtightened screw, please save christmas for me!

[szjon]

First post here, (except for the padding 5)

Sorry to jump straight in with a request for assistance but I am in need of advice and quick.

My daughter wanted something for christmas to play music on, I had a budget of about 150 euro, she uses mostly youtube on her laptop through HDMI to her tv. It is tinny as hell and she wanted bass. I showed her 5.1 systems at pc world, she was not impressed. Neither was I to be honest.

I bought a set of mission 701s for her from the bay and an amp. The 701s came and look great. I hook them up and there is great sound until you try the bass. It sounded like a skeleton masturbating in a steel box while on meth. (HT harry)

One of them was vibrating like an Ann Summers party gone postal, I was cringing.

Anyway, I'm a bit drunk, (please note the time and date).

I have found the culprit. The driver has 4 screws, one of them has been overtightened and has no tension at all. It just turns. Pretty pissed off at the seller but I have to get this working so I'm not returning them. When I press the offending bolt with my thumb the speakers sound excellent.

I have never opened a speaker in my life but I'm pretty mechanically minded and have a good toolbox.

Some questions.

1. When I remove the 4 torx bolts, will anything spring out at me?
2. Is there a gasket/sealant on the unit?
3. Is the box made from MDF?
4. Is there a specified torque for these screws?
5. Will a split match and a dab of pva be enough to fix the stripped screw tension?
6. Is there anything else I should do while I have them open?

Many thanks for any assistance.

[blackraven]

The cabinet is probably MDF. Nothing will spring out at you. I would try and repair the screw hole with JB Weld and then redrill the hole when it dries. Thats pretty $hitty that the seller sold it to you that way. I would send him a nice little package of dog poop!

J-B Weld Company - J-B WELD Product Information -This stuff works great. It is hard as rock when it dries.

Good luck!

[JohnMichael]

I would coat the screw with a wood glue and reinsert the screw. The glue will adhere to the MDF. The glue will harden and then you can snug down the screw. Of course it may take 24 hours for the glue to set. The glue will adhere to the cabinet and create threads for the screw. Of course you cannot play the speaker until the glue is set and dry.

[szjon]

OK, so I took out the offending torx screw and a thin coil of plastic came out with it. So I removed them all and took out the cone, I could see the plastic protrusion was split. So I cut a long, thin piece of plastic from a rawlplug with a craft knife dropped it in, dropped in a few drops of superglue and screwed the screw back in, it now nipped up tight without issue.

Thinking I had just saved the day I set them up, tested and had the same issue. A bit more investigation and the vibration is coming from the plastic baffle where it joins the left side of the case. This has now gone from a small issue to a major repair.

A few pics. The split screw housing,



The rawlplug repair.



As you can see from the pics, I have the baffle out. This was a nerve wracking operation. I used a small pry bar to lever the sides open.



Some of the veneer cracked but it should go back nicely enough, no pieces fell off.



It became clear someone has had a go at fixing these before.



There are two types of glue in here, one is a hard but flexible yellow bead, like a resin, the other a hard white one which I am assuming is PVA.





I removed all the PVA using a file, unfortunately, the soft wood lining wasn't attached to the case in one corner and it snapped when I filed it. Should all glue back OK though. I also noticed the long piece to the left can be lifted away too around 3 inches of it is detached so I will glue this too.



Now researching what glues will be best to rebuild this once it is all back to bare wood and sanded. Will update progress.

[Poultrygeist]

I build speakers and use Titebond wood glue. It sets up in a few hours and is stronger than the wood itself. Clamps are usually needed.

[szjon]

I'm thinking of using nylon ratchet straps instead of clamps as they bevel inwards. I'll belt the box then lie it face down with some weight on it to compress it evenly.

I'm not sure just wood glue is going to do it. It looks to me that there are 3 glues. The wood glue, where the mdf joins mdf. Some other glue on the thin softwood lining the baffle sits on, the baffle is plastic. Then there is the yellow resin like bead around the recess. This looks like it provides compression onto the plastic baffle from the sides.

I wish the seller were here now, I'd kick him in the nuts.

[blackraven]

Gorilla glue might work.

[szjon]

So, I went out today to find all the hardware stores closed. I ended up, (after a few hours looking) in a supermarket and the best I could come up with was regular wood glue and some no more nails, I also had some Polish wood glue (kley do drewna) I have from a few years ago.



Decided to go ahead with this, I wasn't quite sure how to go about this so I spent the day working a plan of action. The following is just what I had to hand and I'm sure there are better ways of doing this, my way throws up problem after problem, I solved them all in advance and prepped each stage but this is probably an overcomplicated way of going about this and I have never done this type of thing before, this is just my attempt at solving the issue. I don't recommend following this as advice. I've never opened a speaker in my life. We will see if it is succesful in 24 hours.

First I cleaned up the rest of the old glue and used the Polish wood glue to stick down the softwood gasket that was loose on the left, the plastic baffle sits on this, it is almost like balsa wood. I also reattached the piece I broke off when I was filing the glue off it. I wiped off any excess glue with a lightly dampened cloth, waited a few minutes for it to get tacky so it wouldn't move and flipped it over , this was tricky as the flaps are only held on with the veneer. I put some pressure on it to compress the gasket, I'm sure this is overkill but that's how I roll.



The Polish glue apparently dries in 40 minutes, I left it for a couple of hours while I prepped some other stuff. I started making a frame.

I had an issue with the flaps springing back so I cut some plastic wall fastener i had to use to hold them out of the way. They were about 15mm long. This was to keep them out of the way while I applied a bead of the no more nails to the baffle gasket. (the no more nails claims to be flexible and gap filling, I thought this would provide better damping and seal than the wood glue that dries rock hard.)



Trying to keep a bead with such a stupid little squeezy bottle was a nightmare. I filled the gaps after I took this pic, then I placed the baffle, it only sits on the inside 2.5mm of the gasket and leaves 2.5mm protruding around it. I pressed it down and used a small pry bar to take away the excess glue from around the edges. There was quite a lot. I wiped off any excess that had got on the baffle as it dries off white with a lightly damp cloth and wiped it dry with a dry cloth.



I had watered down the polish glue and I used a paintbrush to give a good coat in around the veneer where it had peeled from the case. I also gave all the wood parts that had contact a quick wash with it. I then ran two beads of the other wood glue. One around the outside of the gasket holding the baffle to the case and one inside the rebate, I also put some on the mitred corners in the vain hope they would line up. Closed all the flaps and started to strap her up.

I used some ratchet straps I bought 2 years ago for 2.99 euro in Lidl. (First time out of the wrapper) I used a skipping rope and some funky knot tying.





It doesn't look it but there is quite a bit of tension here.The corner mitre joints don't line up. (They didn't when I got them)

I put the frame I made on it. I measured it up and it will compress the wood flaps against the baffle (I cut some grooves for the skipping rope, it's in the following pics) It is just held together with some small pins I had handy. I used a belt I had from tv wall bracket to give it some strength and adjustability.



Nice fit.





A bit of teasing and a bit of balancing and I ended up with this.



I reckon there is my own bodyweight on there. Will see how it comes out in 24 hours. Corner mitres are still well apart, I'm not holding out much hope for this repair but I'll see when it is cured.

I have a feeling that building a new box for the components would be easier than trying to repair a box that was already badly repaired.

[Poultrygeist]

With the pains you've taken it's obvious you've enjoyed the effort. You seem a candidate for DIY speakers far better than the Missions.

Anyone who keeps brake rotors around the house is a DIY guy.

[frenchmon]

Now thats the way I would have done it....Rig it all the way, ifn proper tools where scarce.

[TheHills44060]

Hope everything all works out szjon. I bet your daughter will be proud to have those speakers!

[szjon]

With the pains you've taken it's obvious you've enjoyed the effort. You seem a candidate for DIY speakers far better than the Missions.

Anyone who keeps brake rotors around the house is a DIY guy.

Completely new to all this, I am running a set of mission 753s from a technics suv450, mainly used to run my digital tv through.

I was bidding on a cambridge audio amp from the same seller I bought the 701s from but was outbid so I scanned his other offerings and ended up with a Yamaha DSP-A592 Home Cinema Amplifier (to save postage) This arrived damaged with the 701s but it works, damage is cosmetic. (I'll be having a go at repairing that too)

I bought another cambridge audio for her and I am now looking at all the options on the yamaha and thinking of ways to use it with my tv.

If the 701s still vibrate after this attempt then I might just buy something else for her and build new boxes for the 701 components and use them as rears to my 753s.

Looks like I've found another rabbit hole to fall into. My wife is already pleased I've found a new hobby.

[szjon]

Now thats the way I would have done it....Rig it all the way, ifn proper tools where scarce.

I surprised myself at some of the improv here. I'm especially proud of the locking slip knot I came up with for the skipping rope. I'll make a boy scout yet!

[szjon]

Hope everything all works out szjon. I bet your daughter will be proud to have those speakers!

She loved them, she was over the moon, then she turned up the bass and played this through them.

DJ Koltsov Ft. Alex Rostov - Storm [Original Mix] - YouTube

About 1 minute and 48 seconds in showed up the problem. Watching her smile slowly drop was heartbreaking. If this repair works I'll be a hero, it is the first time she has taken any interest in any of my 'hobbies'.

After hearing this I'm starting to wonder what we have let ourselves in for, teens and volume control. Hmmm.

[szjon]

So, a progress report.

It didn't turn out as well as I hoped. There are 1mm gaps on each corner.





the veneer has not gone back correctly where I broke it.




But, drum roll please......


They sound great with no vibrations!

Got a very happy daughter, she is not interested in the damage to the veneer, doesn't care about the gaps, (I'll probably tidy them up with black silicon or some wood fillers and veneer) but she got that sparkle in her eye when she heard them and I got the hug of the year, even made my wife happy.

All in all, a resounding success. I'll see how long it lasts. I don't expect too long but I'm looking for another pair for her, (that crack in the veneer is a bit more structural than it looks) I'm not really happy with the outcome but it buys me some time to find another good pair, (they are quite remarkable for the money I paid) I'll use the components from these to build my first speaker cabinets, they sound good after my bodge repair and the bodged repair before me. Can't be that hard to knock up a box for these, a good first project.


Now to try and fix the yamaha I got from the same seller, damaged in transit (due to his merde packaging.)



He sat the speakers on top of it in the box. No protection between. but anyway, wrong forum.

The good news is that I quite enjoyed doing that and reading around the forums I am starting to get an interest in developing my sound at home. First I'm going to bi-wire my 753s.

I used to love my music and it's a long time since I sat down and listened to any. (teen, toddler and baby) As I think about this now, it has been ten years since I last sat down and listened to a whole album all the way through. I am restricted to listening in my car, (it's a good set-up) but I don't really listen. This is going to change.......

I can't believe I have forgotten about these things. Peer gynt and the piano concertos, dvorzak's 9th, beethovens too. The wall, animals, the score. Massive attack! Argh!

I used to spend so much time with music, I have suddenly realised I need to take back some time from my kids. 5 hours a week is fair I think.

I'm going to need some equipment......

I'm also going to need some advice. I'd appreciate any input on this thread.

(Will link after I've started it)

Thanks to all who offered advice and encouragement on this thread.

[Poultrygeist]

You can fill the cracks with auto body filler ( Bondo is the common brand in the states ). Then sand carefully, mask, and spray paint just the small repaired area or use a Sharpie black permanent marker.

[JoeE SP9]

My advice would be, never buy anything else from that guy!

[Worf101]

But I'm in love with this thread! Thanks man for taking us on this weird journey. I love buying used stuff on the bay BUT I'm not as handy or patient as you when it comes rebuilding broke down stuff. I like my vintage and low rent finds to be functional right out of the box.. Still I love your story AND your photo's. Bravo man, thanks for entertaining me on this cold winter morning.

Worf

[blackraven]

But I'm in love with this thread! Thanks man for taking us on this weird journey. I love buying used stuff on the bay BUT I'm not as handy or patient as you when it comes rebuilding broke down stuff. I like my vintage and low rent finds to be functional right out of the box.. Still I love your story AND your photo's. Bravo man, thanks for entertaining me on this cold winter morning.

Worf

Agreed! I think he deserves a greenie!

[Poultrygeist]

The speakers are not difficult to repair but the amp is a different story.

[szjon]

Thanks for the support guys. I haven't done the cosmetic work on the speakers yet, been busy with other things. I will post pics when I get round to it.

At the moment I am trying to find some stands for them, I am shocked at the prices these command. I'm looking into designing them myself and getting my local engineering shop to weld them up for me. I can paint them myself. This will also allow me to have the correct height for her room.

I will update this when the job is done.

[Poultrygeist]

szjon,

Here's a link to the DIY Stubby speaker stands. I've built 4 or 5 pair as well as a HDTV top mount center speaker stand using twin PVC columns. When you fill the PVC with sand it makes for a very stable stand. I mitered and stained some molding to dress the sides which makes for a nice finished appearance.

TNT-Stubby - A DIY Speaker Stand Project on TNT-Audio [English]

[smokinjoe73]

I know this is a late comment but I have had good results installing triangular gussets in the corners when doing similar rebuilds. It squares up and solidifies the joints. Also you can screw into them if needed and bodyfill the screw heads.
Also, since stability is paramount for acoustic quality, you can put steel L brackets in the corners with the same results, screwing from the inside with screws that are just shorter than panel thickness. (this in addition to the glue job)

[budgetaudio76]

cant say im surprised at the results. As those come alongs will put quite some pressure where tehy are applied. Thus resulting in teh wood bowing. But the glue holding it together is stronger then the wood. And as long as there is a good seal should never be a problem.