View Full Version : EMIT & EMIM Tweeter Diaphragm Repair How To


Kencat
04-06-2006, 10:04 PM
I successfully brought 2 EMIT diaphragms to life tonight. Surprised the heck out of myself actually. I did it just to see what would happen figuring I couldn't make a bad one worse.

The diaphragms I worked on were for the Quantum 2. I think this would work on other models as well. A brief history to get started. I had one Emit that was not working in one speaker. I picked up some spare diaphragms and proceded to change out the bad one. I found that the resistance of the bad one was 20 - 40 Ohms. I knew at that point that at least the foil was not broken, and looking at the solder joint suspected that was the problem. The good diaphragm measures 5.6 - 5.8 Ohms.

I ordered some more diaphragms lately, and one of the two measured 30 - 40 Ohms. This prompted me tonight to see if the solder joint could be repaired with with a remelt of the solder that connects the back-side metal frame to the leads of the foil strips on the Mylar-side. The winding foil strips I call the "racetrack".

I fired up the little Soldering Gun, using the pointed tip, and bravely touched each button on the frame-side, just long enough to melt the solder, and quickly removed the tip.

Word of caution: I had the mylar-side on top of newspaper, which was a good thing because the solder tended to fall downward and without coming to rest on the paper, it may have fallen right out. You can see in one the pics how the solder is raised on the mylar-side. I may have had the tip on the button too long for the first one, and made sure I was quicker on the second one.

BOTTOM LINE - It worked. Measured 5.7 to 5.8 Ohms rock solid

Below are the two Q2 EMIT Diaphragms and the tools of the trade.

http://audiokarma.org/forums/attachment.php?attachmentid=12745&stc=1

Below is the Frame-side of the Emit diaphragm showing the solder buttons. This is the side to "remelt". Ignore the big solder blobs. That was where the speaker wires were soldered on. It's the small buttons that connect to the foil.

http://audiokarma.org/forums/attachment.php?attachmentid=12746&stc=1

Below is the Mylar-side of the Emit diaphragm showing how the solder will tend to flow with gravity.

http://audiokarma.org/forums/attachment.php?attachmentid=12747&stc=1

SO, Don't chuck out those non-working Emits without checking the resistance. If it's high, it's not broken. This solder joint remelt might be all it needs.

Charivari
04-06-2006, 10:45 PM
Great thread, Kencat. This problem is very common, having encountered it recently myself. Hopefully others will realize that they can repair their bad EMITs rather than resort immediately to replacement.

- JP

SicMan
04-07-2006, 02:12 PM
Thanks for the info KenCat.. I may need to check one of mine, it sounds very weak. I've been lucky with the emits but my problem is the Mids....

All this speaker talk made me pull the trigger last nite on a set of Kenwoods but I think the price was right, I'm putting a Kenwood system together for my daughters boyfriend. Like I need more speakers. The wife thinks I bought them for myself. Lets see,... where can I put these....

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9706209028

I know it's a little off topic.... Sorry... :twak:

thedelihaus
04-07-2006, 02:49 PM
Kencat,
Thanks for sharing this tip- seems there's a million badEMITs out there that might not be bad after all.

sicman,
Good luck with the Kenwoods. I was eyeing the seller's Advent Legacys myself...

But I've got a few offers here from some AKers that I'd rather take care of first. I think.

Army
04-07-2006, 03:20 PM
Excellent thread Ken!

I was wondering when someone would post a thread like this. It is a source of frustration for many Infinity speaker owners.

I don't have any emit or emim's to experiment with that need repair. But I did pick my friend Jims brain on repair technics.

From what I gather most short out in the area shown in your third photo when overdriven with out enough power.

Jim takes an eraser and scuffs up the ends at the short, then uses scotch tape and masks off each section of mylar, so as not to creat another short. Folding the ends of the tape for easy removal. Then uses a silver based conductive contact pen from Parts Express. Once it dries two light coats of clear fingernail polish. He repaired my emim's about a year ago and they are still playing great :thmbsp:

OMI
04-07-2006, 03:21 PM
Just measured mine at the office... 3 and 29... I have a BRAND NEW soldering iron at home that will come to work with me on Monday for a little bit of DIY:)... Now the speakers sound GOOD now so after a lttle doctoring.... Hmmmmmmm Will see on Monday:)

macaltec
04-07-2006, 10:45 PM
Just measured mine at the office... 3 and 29... I have a BRAND NEW soldering iron at home that will come to work with me on Monday for a little bit of DIY:)... Now the speakers sound GOOD now so after a lttle doctoring.... Hmmmmmmm Will see on Monday:)

Cool, a good reason to go to work. Don't hear that too often. Kencat, great documentation and pics. Useful information for the future.

Negotiableterms
04-08-2006, 01:35 AM
Great thread!

What does everyone think of a subforum called: "Repair and Parts"? If there's enough interest, Scott or I can ask the admins to clutter up the server just a little bit more...

Charivari
04-08-2006, 02:33 AM
A minor addition is that the older diaphragms don't have the etched '+' at the bottom, but have merely a red marker blotch near the positive terminal. An additional, but unimportant detail is that with the older the builder/assembler/QC wrote the impedance of the diaphragm (typically 5.6Ω ) at the top in red ink. Of course, the diaphragm alone measures as a dead short (the interaction within the magnetic field creates the impedance), so this bit of information was likely used for matching before assembly.

Something very important to remember when attempting Kencat's described repair on assembled EMITs is that the rare Earth element Samarium-Cobalt magnets are very strong and very fragile. Where this information becomes important is with the recognition that the glue holding the magnets to their respective halves of the housing has broken down in the intervening 30 years. So, a jig utilizing a board and non-flexible rods through the outer screw holes must be employed to prevent damage during disassembly and reassembly.

This is hard learned knowledge from today. When attempting to determine the cause of a severe mismatch in tweeter levels and roll-off between my two Quantum 2s, I discovered that the rear EMIT (4x4 slot arrangement vs. 2x8 of the front EMITs) was measuring nearly 50Ω. I had repaired one 2x8 EMIT a few weeks back using Kencat's idea when he first mentioned it without difficulty aside from a pinched finger tip. However, the rear EMIT's square shape prevents any torsional control compared the other's rectangular shape. The bad glue made this a destructive effect rather than just an inconvenience. The magnets repelled/attracted each other with a couple dozen lbs of force (in a very small area) causing 3 of the 5 magnet strips on the front plate sans glue to slide and roll when the plates snapped together with great force. The result is that two snapped into at least three pieces and the diaphragm was torn in a couple of places. Thanks to the nature of magnets what was once one magnet is now several making for realignment and regluing quite difficult, but hopefully the performance should still be relatively close to normal. I'll deal with this issue later, but I needed to share this warning.

- JP

Kencat
04-08-2006, 12:19 PM
Great thread!

What does everyone think of a subforum called: "Repair and Parts"? If there's enough interest, Scott or I can ask the admins to clutter up the server just a little bit more...

Do you mean a subforum under the Infinity Speakers Forum? (maybe a silly question but just making sure :D )

Would a sticky do the same thing?

Army
04-08-2006, 12:48 PM
For now I think we'll just sticky this thread.

At some point in the future we probably will look at a sub-forum for repairs and parts or some such.

Also we don't want to have too many stickies either, because it looks cluttered.

But this is a common problem for older Infinity speakers and I think very valuable information.

One thing I forgot to mention about repairing the emits that Jim told me he did to keep from breaking the magnet was he would use a longer set of screws to hold them in place. Does that make sense JP? I have yet to experiment with any.

Kencat
04-08-2006, 01:12 PM
Of course, the diaphragm alone measures as a dead short (the interaction within the magnetic field creates the impedance), JP

JP, please explain "dead short". :confused: I measure 5.6 Ohms DC on the diaphragms with the meter. In fact, are these tweets actually not a pure resistive load to the amp (or at least primarily one) vs a reactive load?


Something very important to remember when attempting Kencat's described repair on assembled EMITs is that the rare Earth element Samarium-Cobalt magnets are very strong and very fragile. Where this information becomes important is with the recognition that the glue holding the magnets to their respective halves of the housing has broken down in the intervening 30 years. So, a jig utilizing a board and non-flexible rods through the outer screw holes must be employed to prevent damage during disassembly and reassembly.

This is hard learned knowledge from today. When attempting to determine the cause of a severe mismatch in tweeter levels and roll-off between my two Quantum 2s, I discovered that the rear EMIT (4x4 slot arrangement vs. 2x8 of the front EMITs) was measuring nearly 50Ω. I had repaired one 2x8 EMIT a few weeks back using Kencat's idea when he first mentioned it without difficulty aside from a pinched finger tip. However, the rear EMIT's square shape prevents any torsional control compared the other's rectangular shape. The bad glue made this a destructive effect rather than just an inconvenience. The magnets repelled/attracted each other with a couple dozen lbs of force (in a very small area) causing 3 of the 5 magnet strips on the front plate sans glue to slide and roll when the plates snapped together with great force. The result is that two snapped into at least three pieces and the diaphragm was torn in a couple of places. Thanks to the nature of magnets what was once one magnet is now several making for realignment and regluing quite difficult, but hopefully the performance should still be relatively close to normal. I'll deal with this issue later, but I needed to share this warning.

- JP

This is a very good topic to mention JP. When I took mine apart I was dumb lucky in that I had a good grip on things and after the last screw came out I let the two halves come apart quickly and in-line with the magnets.

It is important for anyone attempting to disassemble these Emits to understand that the magnets in each half are opposite each other and the forces repel. As you are loosening the screws, the two halves try to open up. The magnets must be kept lined up to maintain the repulsion as they separate.

I also found out the hard way when assembling mine with the new diaphragm. As I brought the two pieces together, they twisted and shifted such that the repulsive force became attractive, and they snapped together like a 10 lb. clam on steroids. I wish I had a picture of what the look on my face was....I'm sure it was pretty funny. I think I sat there staring at this for 5 minutes wondering what the hell happened and pulling on it wondering how the hell I was going to get it apart. That attractive force is VERY powerful as JP alluded to.

They did finally come apart with some real hard tugging and the diaphragm survived (could easily have been destroyed though). To re-assemble the second time, I built everything up from the front face with the screws in place to act as alignment pegs, and brought the back half into place onto the screws.

http://audiokarma.org/forums/attachment.php?attachmentid=12882&stc=1

http://audiokarma.org/forums/attachment.php?attachmentid=12883&stc=1


As JP has said, planning this before-hand is wise. If I were to do it again I think I'ld make up a jig to keep the two halves lined up. An arrangement of dowels in a board would probably do, with the dowels fitted closely to the sides of each half.

EDIT - Didn't see your post Army, while I was putting mine together. The longer screw idea is good, but you have to get the originals apart 1st, which is probably less risky than trying to put them together.

At least understanding the problem will allow others to come up with creative solutions :thmbsp:

Kencat
04-08-2006, 01:42 PM
Here's a bunch more pictures of the Emit in pieces, that might be helpful for anyone going into a repair. This is the Quantum 2 Front Emit tweeter.

Charivari
04-08-2006, 05:31 PM
JP, please explain "dead short". :confused: I measure 5.6 Ohms DC on the diaphragms with the meter. In fact, are these tweets actually not a pure resistive load to the amp (or at least primarily one) vs a reactive load?
I was tired and frustrated when I wrote my warning, having just again unsuccessfully attempted repairing that particular EMIT. Like a dingus, I had inadvertently shorted the terminals where I had placed the diaphragm. Yes, on its own, the trace does measure 5.6Ω on the ol' Simpson (and something really weird on my trippy Triplett).

Army, thanks for the suggestion, it should make for nearly as easy repair as a jig would. Should've thought of it before attempting another repair, but such is the nature of experience. To clarify, there are six screws that hold the EMIT halves together. By pulling the four corner screws, leaving the middle two in place, and replace with longer screws, alignment should be maintained while adding a guide. The only issue I can see here is that the threads will likely catch on the front half and thus make it difficult to press the halves together smoothly and evenly. Also, the EMIT will not be attached to a firm base as it would with a jig and so make it a bit more difficult screwing in the center two screws one-handed.

- JP

OMI
04-08-2006, 07:22 PM
I have had the tweets on my QAs apart a few times now. One time they did slide over and WHAM together:( What seems to work for me now is that I place everything back in order and have the 4 screws placed in the front piece. I find that I can hold the back magnet in place over the front magnet and lower the back end, the end opposite the connectors, down on the 2 screws and then pick up the tweet and get the 2 screws started so that they "take hold" of the back magnet. Once that is done, they are "locked" in place and it is a snap to start the other 2 screws. Then tighten them up...

I take 'em apart in the opposite order... Loosen the screws so that they are ALMOST out and then take out the 2 screw at the top. The magnets push apart and HINGE at the back 2 screws. Hold the tweet tight and take the last 2 screws out and no WHAMMING...

Vitopanch
04-09-2006, 03:22 AM
Nice. Just getting back into town from a business trip I was hoping that there would be a great thread started for me to read during a coffee and HERE IT IS.
Many thanks,
Vito

OMI
04-10-2006, 08:37 AM
OK...

Hit the tweet first thing when I got to work... Was reading 29.......

NOW READING 3.2 :banana: :banana: :banana: :banana:

I did not get the iron so hot as to melt the solder with one touch... The iron was hot enough to take the dark oxidization from the solder contact and soften it up... That seemed to do the trick.... For me at least....

Your mileage may vary...

:banana: :banana: :banana: :banana: :banana: :banana:

Listening to Kaki King now...... :banana: :banana: :banana:

Kencat
04-10-2006, 08:41 PM
OK...

Hit the tweet first thing when I got to work... Was reading 29.......

NOW READING 3.2 :banana: :banana: :banana: :banana:

I did not get the iron so hot as to melt the solder with one touch... The iron was hot enough to take the dark oxidization from the solder contact and soften it up... That seemed to do the trick.... For me at least....

Your mileage may vary...

:banana: :banana: :banana: :banana: :banana: :banana:

Listening to Kaki King now...... :banana: :banana: :banana:

Omi,

Do you notice a difference in the sound?

OMI
04-10-2006, 08:55 PM
There seemed to be an improvement. I had a new soldering station, and one bud at work said I needed to tin the end to get it to do a better job of transferring heat and melting the old solder. As it was, it would burn wood (turn it brown where I touched a small piece of wood), but it did not get the 2 solder points flowing. I guess that was a good thing, as it appeared to get the solder soft, but it did not get the solder to “flow”. I did not want to push my luck and burn the Mylar base material...

I used a small piece of veneer (1/2 by 3/4 inch) as a base on the back side of the mylar (let the back side of the 2 solder points rest on the veneer), as I heated up the "front" side of the 2 points.

Will give it a week or so and will re-measure....

ktpma
04-15-2006, 12:18 PM
i do have problem in my Qe speaker emit tweeter ,
imposible to replace other type of tweeter like horm type? or other type ? i not known much in this,if can replace what is the watt ? i have see the repair guide ,thanks and useful but mine is beyond the repair . i need buy new diaphragm so expensive .but i like to keep this my old buddy too long with me , please help me to save .

thanks all of u.....

Kencat
04-15-2006, 01:59 PM
i do have problem in my Qe speaker emit tweeter ,
imposible to replace other type of tweeter like horm type? or other type ? i not known much in this,if can replace what is the watt ? i have see the repair guide ,thanks and useful but mine is beyond the repair . i need buy new diaphragm so expensive .but i like to keep this my old buddy too long with me , please help me to save .

thanks all of u.....

Hello ktpma......welcome to Ak. All the way from Singapore eh? Good stuff. The world is a small place now with the internet. I think you'll find this a worthwhile site to be a member of.

A few questions. (1) Why do you say the tweeters are beyond repair ? (2) Are you able to get replacement diaphragms in your area? They are approx 50 $US from the states. How much in your area? (3) what about Ebay or other used sources? Have you looked there?

I've measure the DC resistance on this diaphragm and it measures about 3.7 Ohms. Omi measured 3.2 Ohms on his, so a good guess would be that you would have to replace the tweeter with a 4 Ohm impedance driver. Unless someone else has done this exact replacement, I think it is very hard to advise you on what replacement driver will work. There are many factors that come into play, and the crossover point has to be matched (2,500 Hz according to the spec sheet at http://www.infinity-classics.de/infinity/manuals/Qe_technical_sheet.pdf ). You may into experimental territory here.

But, wait a while, and more members may reply with more information.

ktpma
04-17-2006, 09:41 AM
Hello Kencat ...
thank for ur care and internet too. Ans (1) ribbon are cut badly and lost some part.(2) price approx S$90 for 1pc (3) can't see in ebay .i take ur advise and wait some one guidance...
thank alot

banffskiing
05-20-2006, 08:37 AM
Ken
Just read your post on repairing the emit tweeters. That's pretty cool that you actually get inside them like that. Looks like you repair was near the edge of the ribbon. That would be a real nasty job if it were some type of voice coil with a million turns. Your repair looks like it was on the edge of the ribbon and not somewhere in the middle. I have also heard of using a rear window de-icer kit to repair the coil itself. Another option might be to use conductive pin (CW2200STP). It is mainly used for repairing circuit boards and has high silver content, which makes it very conductive. I think the less mass you add especially towards the middle, the better off you are.
Adding to much weight would affect the high freq. response of the tweeter. They also make solider that has a high silver content. It might be more expensive than the regular stuff but it flows much better. I use to use it for repairing medical electronics that had surface mount components. Anyway nice job and great pictures.

Vitopanch
06-05-2006, 02:15 PM
Hail,
Seeing that there are some EMIT's and EMIM's for sale ATM, I pose the following question; do the EMIT's or EMIM's themselves actually break, making back up's beneficial, or is it just the diaphragms?
Vito

Kencat
06-06-2006, 10:28 PM
Vito,

There is not much to go wrong with the framework and magnets that I can see. JP (Charivari) did report some magnet breakage I think (after some unplanned whackamoles with taking Emits apart IFRC) in a post of his.

The diaphragm is the most likely culprit for failure....the solder joint, or the "racetrack"/ "windings" being broken. Problem is, the diaphragms are hard to get. Not made anymore I don't think.

So.....the diaphragms are best obtained with the entire unit I quess.....unless there are still some sources of the diaphragms still out there.

brainsmasher
06-07-2006, 08:53 PM
Here goes another Thank you to kencat. I bought a pair of foster ribbon tweeters today which are essentially the same thing as an emit. First did not work at all, upon taking it apart this tweeter had a rough life it was smoked. Checked the solder joints and nothing, did a little more digging and found a busted lead, little bit of soldering and bang zoom it works now. Second was dead, hit the solder joints and houston we have lift off.
Never give up never surrender

banffskiing
06-12-2006, 10:58 PM
Measured the resistance on one of my emits today and got a reading of 30ohms.
Decided to try some of that liquid copper stuff that is used in rear window defogger repair kits. After prepping the area with a little sand paper, I coated the joint where the electrical connection meets the ribbon track. I let it dry for a few minutes and re-measured and got 6 ohms. Thought if this worked it would be an easier fix that using an iron. Anyway here are my words of wisdom, very inportant to use some type of jig or longer screws as mentioned eailer in this thread. THiswill keep the spacers from moving around as your putting it all back together, otherwise you get something like the picture below. Oh well, hard lesson learned. Anyway I will try the liquid copper again as I am sure I will find at least one more bad unit on the other qls-1.

Banff

Tronhead
01-28-2007, 08:32 PM
The broken magnets must be replaced. They make new north-souths that wont go back together again. Maybe you can get away with putting one that was only broken in half back, but from my experience, and I have seen them in 7 or more pieces and it don't work. I used to repair them under warranty in the 70's and 80's. Good luck.

Army
08-23-2007, 08:37 PM
I had a couple of emim's go out on my RS 4.5's the other night, swapped a pair out of my RS 2.5's so I still have tunes, thankfully.

So today reread the emit repair thread and decided tonight I'd screw up my courage and at least try to see what was the problem. One measured 68Ω's and the other 45Ω's so I had a feeling they weren't toast since I still had some resistance.

There are six screws that hold them together that use a cap type of nut with a shallow phillips head. I loosened them before I made a crude fixture out of a 2x10. I took the four screws on the sides completely out. Them grabbed some 16 penny nails and nailed the emim with contacts down to the board leaving about 1.5" roughly above the emim. Cut the nail heads off with a bolt cutter. Which gave me enough room to slide the emim up enough to get the last two screws out. I carefully lifed the top section off enough to see that there are two more brass screws that bolt into the board that holds the mylar in place and makes contact via a wire to the external leads see picture.

Lifting up enough to get the 1/4" brass nuts off the front came off with out problem. I cleaned up the bolts and nuts with brasso (took about an hour). Put the assembly back together which was a PITA to get the tiny nuts back on. I took a measurement a crossed the screws before I put it back together and got 3.4Ω's but once I put it back together it read 7.6Ω's Better but not good enough, should have removed the brass nuts that hold the external leads on and cleaned them I guess...

When I get another chance I'll tear it back down and go and find new nuts and bolts and try again. Corrosion is definitely the enemy...

Army
08-23-2007, 08:46 PM
Good news, replacing all the screws which were 4-40 thread by 1/4" long on the mylar board and 3/8" long for the terminals resulted in a working emim :thmbsp:

I also took Ken's advice (http://www.audiokarma.org/forums/showpost.php?p=1311008&postcount=7) and hit the solder joints on the lead wires and polished the terminals with brasso.

zenithradio
08-25-2007, 01:06 PM
the idea behind the nails?? is that to keep everything lined up. i did hear something about having to press both sides together because of the magnets. supposed you just took it apart??. would you be able to get it back together by your self or you would need help.

zenithradio
08-25-2007, 01:22 PM
what about these from orange county speaker, wouldent they work for anybody looking for a replacment??.

Charivari
08-25-2007, 01:39 PM
the idea behind the nails?? is that to keep everything lined up. i did hear something about having to press both sides together because of the magnets. supposed you just took it apart??. would you be able to get it back together by your self or you would need help.
These drivers use very powerful rare earth samarium cobalt magnets (the HE versions use neodymium) that react faster and more strongly than whoever is taking apart the drivers. Were they just pushing the halves apart, that wouldn't be such an issue. The trouble is that while the magnets repel when aligned, they strongly attract when slightly off to the side. So, when the screws are removed on one of these drivers without the nails (or longer screws to ease the halves apart as per my preference), one half will move in relation to the other and both will snap together with significant force. This results in not only very pinched fingers and a subsequent difficulty in prying the halves apart, but the movement also tends to shred the diaphragm. In some cases, the glue holding the magnets has sufficiently weakened that the shearing-snapping process can break some magnets loose and they subsequently can shatter during this unfortunate happening.

Simply put, don't attempt disassembling an EMIT and especially not an EMIM without some means to keep the halves aligned else you'll likely have an irreparably damaged driver and very sore finger tips.

- JP

Charivari
08-25-2007, 01:40 PM
what about these from orange county speaker, wouldent they work for anybody looking for a replacment??.
They should work fine, but they are costly. Why outlay the money when the existing diaphragm can be made good as new with a little effort that's equivalent to what would be needed to install the replacement anyways?

- JP

zenithradio
08-25-2007, 01:50 PM
i was just thinking for someone who had emim,s that needed a new diaphragm. i know they are costly,but if you needed one, its better then nothing. thanks for the info. my 1b's are working well now, but hey,you never know

MagicMarksy
08-30-2007, 12:42 PM
Why Arnie Nudell and Infinity never made any DIPOLE EMITs is beyond me. The design of the EMIT is just like the EMIM and you all know how well the EMIM works as a dipole speaker. Well the EMIT will work the same way as well.

http://launch.ph.groups.yahoo.com/group/InfinityClassics/photos/view/2a95?b=1&m=s&o=0

Follow this link I previously posted on the Yahoo Infinity Forum on how to take 2 normal monoplar EMITs and reassemble them as a single dipole EMIT.

I know this can get expensive as for every one dipole EMIT you want to make you need to start out with two monopole EMITs...but believe me the time, expense and effort is worth it.

To date I have never heard a better tweeter than a DIPOLE EMIT and I have been making them for over 25 years.

I have made hundreds and have them out in the field in many of my speakers and everyone swears by them.

I am sure you will too.

This thread is also helpful for anyone wanting to take apart and repair any EMIT driver as it is all explained in easy pictural format.

If anyone has problems accessing these pictures let me know and I will sent them to you directly via E-mail or repost them here on this forum.

Finally note:

The tall 7 inch EMITs (like in the Quantum Series) are called FULL LINE SOURCES and should measure about 5 Ohms

The short 3.5 inch EMIT's (like in the IRS and RS Series) are called 1/2 LINE SOURCES and should measure about 3 Ohms.

Any EMIT that measures significantly different than these DC resisitance values is an EMIT that is malfunctioning. Sometimes resoldering the connections, as pointed out above, will fix the problem, but please be careful.

Also not all broken magnets need to be replaced. Superglue and epoxy are very effective at putting them back together and once reattached they function just fine. (you need to coat them with standard mylar "Scotch" tape to prevent shorts against the diaphragms - most original units used YELLOW mylar tape - if it comes off or bubbles you need to replace it)

Also for those of you that need magnets or spare parts I have a house full of them. I can usually help with most EMIT repairs.

O.K.

MichaelAlanMarks@aol.com
pm me for my phone number.

MagicMarksy
08-30-2007, 04:48 PM
Here are some representative pictures of what my DIPOLE EMIT tweeters look like when they are done. Realize it take two normal tweeters to make one of these. So in these pictures where I show a pair....I actually had to start with 4 of them to make these two. Any questions just ask. These are just wonderful to listen to.....much better than the normal EMIT tweeter but your cabinet design must be capable of accomodating the DIPOLE design to make use of them.

For now.



AKA: MagicMarksy on eBay

mywifespissed
01-13-2008, 05:05 PM
I can't find a speacific thread about this so I'll just ask for HELP! here.

I have a buzzing EMIM in my RS4.5. It is infrequent,mild and only shows up during loud piano passages or during some random note. Is there a way to stretch the diaphram tighter? Thanks!!!

bastek
01-24-2008, 06:05 PM
I've heard that heating up the ribbon element with a hair dryer can tighten up the plastic mylar ribbon. You can also try to manually stretch the element, but that's a very delicate operation.

tlgibbs
01-29-2008, 08:19 PM
Great posts in this thread. Very informative indeed.

I had an emit on one of my QLS that was very low output. It worked, but was not very loud. So after reading this thread I decided to take it apart and check it out. What has me confused is that the membrane read zero ohms when I tested it. I pulled two other emits (but did not remove the membrane) and they both read zero as well. I went ahead and did the solder button melt as suggested by Kencat. I also tried the hair dryer trick, which smoothed things out a bit. I put everything back together and noticed some improvement.

I can't figure out why I'm getting zero ohm readings, however. I checked my meter and it is functioning correctly. I stick the probes on the solder buttons - zero. I stick the probes on the terminals for the wires - zero. What am I doing wrong? Any ideas?:scratch2:

Grainger49
01-29-2008, 09:28 PM
I thought I'd throw in here. IIRC, Eastman Air Devices who owned Infinity and KLH at the time, test marked EMITs in the X-Series KLH speakers.

Might be a source of spares? Maybe all you knew that too?

tlgibbs
01-29-2008, 09:42 PM
Here is a picture of the meter. The ohms are at the top in green. When I tested a 5.6 ohm resistor the needle went right where it should, between 5 and 6 on the meter. Shouldn't the diaphragm be the same reading?

banffskiing
01-30-2008, 10:33 AM
TLgibbs

You have one of the analog meters that you set the scale using the dial.
Usually you pick the scale you won't, short the leads together, and adjust it to zero. But if you are reading a 5 ohm resistor correct then you have it set correctly.
Try measuring it from the actual etched trace as shown in the picture but be carefull and don't use the sharp tips of the test leads or you may punch a hole in the mylar. Turn the leads at a slight angle and try it. If you still get zero then you have a short somewhere and you will have to find it.

banff

Grainger49
01-30-2008, 01:26 PM
TLgibbs

You have one of the analog meters that you set the scale using the dial.
Usually you pick the scale you won't, short the leads together, and adjust it to zero. But if you are reading a 5 ohm resistor correct then you have it set correctly.
Try measuring it from the actual etched trace as shown in the picture but be carefull and don't use the sharp tips of the test leads or you may punch a hole in the mylar. Turn the leads at a slight angle and try it. If you still get zero then you have a short somewhere and you will have to find it.

banff

That's quite right. But first zero the meter movement.

BUT FIRST, sometimes, like in winter, static electricity will affect the movement. To discharge any static on the meter lens moisten your fingers, shake off any water, place your fingers on the lens. Static discharged!


Now to zero the movement, turn the meter off. See if the meter goes to zero. If not, adjust the movement screw VERY SLOWLY, VERY CAREFULLY. This screw is to the left of the meter model number, in the center of the meter.

Classic traditional "high accuracy" meters had a mirror on the meter face. You would get the most accurate reading with one eye closed and reading such that the meter needle covered its reflection.

But that was another day. Yeah, I know :boring::boring::boring:

chef free
01-31-2008, 12:37 AM
I can't believe it! I actually fixed a blown EMIT tweeter (and saved my trusty Infinity Qb) with some clear nail polish and some "rear window defogger repair paint" (which seemed to be clear nail polish with powdered copper in it). I tested it in mono and couldn't hear any difference between the tweeters!

tlgibbs
01-31-2008, 09:40 PM
I finally got my ohm readings correct by using another meter. All my diaphragms read 5.6.:banana: However, what prompted me to pull my emits in the first place is that several of them were significantly lower output to the ear. 3 of the 8 were so low that they were barely perceptible. When I had the diaphragms out I used a hair dryer on the yellow mylar to even them out a bit. The hair dryer doesn't make them perfect, but it helps. Since the ohm reading was correct I did not remelt the solder tabs. I did, however, melt the solder where the wire attaches to the diaphragm when removing the tweeters and when I re-attached the tweeters. I added some fresh solder during reattachment. After getting everything hooked back up all the tweeters were virtually the same level. My conclusion? The melting of the solder where the wire attaches to the membrane is at least as important as the solder tabs where the racetrack attaches. I took ohm measurements at both the tabs and the wire connects before reattachment, and there was about 1.5 to 2 ohms difference. That is the tabs measured 5.6 (like they should) but the reading at the wire terminals was 7 to 7.5. I attribute this to corrosion in the solder where the wires attach.

I would suggest anyone who notices different tweeter levels in their speakers to try this "tune-up". It certainly made a difference in my speakers.

One last note: With eight emits in each speaker it was very difficult to determine relative levels with just my ear. Even putting my ear right up against the emit was problematic because it was hard to tell if I was hearing that emit or the one right above or below it. I solved this by using a piece of plastic tubing about 5/8 inch in diameter and about 12 inches long as a "hearing aid" of sorts. By putting my ear at one end of the tube and putting the other end of the tube right in front of the emit, each tweeter could be distinctly heard, and relative levels could be compared very easily. Attached is a picture of my "hearing aid". Levels were checked by using constant test tones of 5, 6.3 and 8 thousand kilohertz.

I now have happy tweeters!:thmbsp:

alvarez
04-03-2008, 06:04 AM
do you think the solder melt process would work on my delta 40,s? as they are the round style. i,ve had some luc in the past replacing square style foils in my old qb,s. isaved 2 emit r,s complete with housing after i got new ones from harmon kardon shipped for around 75 bucks. of course i will have to test first to see if they are still alive. thanks ,alvarez

robcraigw
05-19-2008, 11:27 PM
The nails keep everything lined up when removing the top cover. UNFORTUNATELY, one should NEVER have to continually disassemble speaker components in order to repair them. This drove me absolutely nuts on my QLS-1s and I'm very glad I replaced them with speakers that sound better and don't require this insane maintenance, especailly now that Infininty is owned by the conglomerate Harman.

Tedrick
05-20-2008, 10:07 AM
The nails keep everything lined up when removing the top cover. UNFORTUNATELY, one should NEVER have to continually disassemble speaker components in order to repair them. This drove me absolutely nuts on my QLS-1s and I'm very glad I replaced them with speakers that sound better and don't require this insane maintenance, especailly now that Infininty is owned by the conglomerate Harman.
1) Any speaker, hell any piece of electronic gear, that's pushing 40 years old is going to require some maintenance.
2) Some people (myself included) derive great pleasure in owning, restoring, and maintaining these vintage pieces, not only for the historic value but also because some of them sound incredible. I am comfortable knowing that there are few, if any, speakers available today costing less than $5K that will sound as good as my vintage Infinity's.
3) Not sure what the current ownership of Infinity has to do with anything. Believe it or not, Infinity is still turning out some good-sounding, high-value products.

If ownership of vintage equipment and the maintenance that goes along with them is not your cup of tea, that's cool, and I'm glad you found something that you like that sounds great to you. And that is what it's all about isn't it...what sounds good to you???

Iagent
08-05-2008, 08:04 PM
I think I will try this procedure. Two of my four are inoperative. The worst problem is that Polygraph mid. I also don't care for those funky looking polydomes. I think they are sort of messed up, as they don't really look like domes anymore, but rather an old shriveled up latex thing

Does anyone know od good replacements for the Kappa 8 mids?

Tedrick
08-06-2008, 01:25 AM
I think I will try this procedure. Two of my four are inoperative. The worst problem is that Polygraph mid. I also don't care for those funky looking polydomes. I think they are sort of messed up, as they don't really look like domes anymore, but rather an old shriveled up latex thing

Does anyone know od good replacements for the Kappa 8 mids?
The Polygraph and Polydome are not the same driver. The Polydome is a 3" midrange driver, whereas the Polygraph is a mid-bass/lower midrange driver. From what you describe, you are referring to the Polydomes. When new, the Polydomes used in the early-model Kappas were more or less translucent in color. http://www.infinity-classics.de/infinity/models/Kappa-series-1987/Kappa-8-8A/Kappa_8A_1.jpg
However, they had a tendency over time to turn yellowish-white and become especially if exposed to sunlight. Unfortunately, Infinity does not make them anymore. But, you are in luck. Orange County Speaker sells a drop-in replacement dome midrange driver (http://www.speakerrepair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=02-239&Category_Code=Infinity-Diaphragms) that by many accounts is an improvement over the original Polydome.

Iagent
08-06-2008, 02:41 PM
My polydomes are wrinkled, so I will be ordering the Orange county replacements. The polygraph that was vibrating turned out to be a cracked plastic housing that I epoxied last night at 2:oo AM lol. It works fine, but I will watch for one that is REASONABLY priced to have a spare in case other issues develop. As for the four Emit Ks, the two in front are working and one rear is inop. Two problems on the left rear: Something wrong in the crossover, and also a bad speaker was relocated to that dead position. Actually the problem was with the front Emit k, but I pulled the rear wiring through to the front, to make use of that location rather than the back. I really would like to get thet working though, because I can hear the reflecting porperties of the good one, and I do like it. The bad Emitt looks corroded at the center of the ribbon, and reads open on the meter, so it's going to have to be replaced.

partialrespo
08-07-2008, 12:51 PM
... Orange County Speaker sells a drop-in replacement dome midrange driver (http://www.speakerrepair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=02-239&Category_Code=Infinity-Diaphragms) that by many accounts is an improvement over the original Polydome.


That driver is made by VIFA. Partsexpress have it for $76 http://www.partsexpress.com/pe/showdetl.cfm?Partnumber=264-550

I have recently read that the diaphragm and magnet assembly from the VIFA can be removed and used inside the original polydome trim to maintain the original "Infinity" logo (factory look)

- Kofi

Chuck M
08-26-2008, 11:36 AM
Good info, Max, keep us updated. :thmbsp: Thanks.

vtomike
08-28-2008, 04:15 AM
So i am testing all of my EMIMs and one of them is 2.7 ohms but i get no sound out of it. The others test at around 3.5 to 2.9. What would be the case the 2.7 reading? I am new to this so i need to ask many ?s. I have re foamed the woofers on my 4.5's and have one playing. All i can say is WOW! I took the advice on the amp and am using a Acurus A250. I am following this thread and trying to fix them all myself. Thanks

cdfac
08-30-2008, 10:02 AM
is the silver pen NLA on parts express? i can't find it...

chris

dd123
01-25-2009, 03:01 PM
I have one Qa emit that isn't putting out as much as the other -- the real high frequencies are subdued. Any thoughts on why? I have recapped them and cleaned the pots. The subdued emit measures 2.6 ohms and the other measures 3.0.

With all these great posts I'm getting psyched up for a repair attempt, but I'm ify on three things:
1. What are the magnets glued to? In some of the photos it looks like they are glued to the front face.
2. Since a Qa emit only has four screws, not six, can I safely remove one at a time to get an alignment nail in?
3. Is it best to disassemble with the front face on the bottom or on the top?

Coilvoice
07-21-2010, 01:15 PM
After reading this very informative thread, I set out to repair four emits that were toast! The "race track" part of the diaphragm on all of them had split in more than one spot and were by far the worst ones I have seen to date. For this reason I chose to simply replace the diaphragms with used ones out of a similar Emit rather than to try the Loctite window defogger repair thing.

I took much precaution with the break down of these as I have read much about the dreaded "10 lb. clam on steroids" effect. When taking them apart, I opened them up like a hinge after removing the screws and applying pressure with hands as to not let them twist on the diaphragm. After opening them up I simply switched the diaphragms. Next, I layed the face of the tweeter face down preloaded with the screws (threads pointing up). I then put the diapragm and its back plate slowly down onto the screws acting as alignment pins, applied pressure while in hand started the screws. I placed it back on the bench at this point and tightened it all up. After a check for proper impedance, I then put a dab of glue on each thread end of the screw on the backside of the tweeter as it was from the factory.

I am writing about this in hopes of helping others and NOT to say this is the best way. I just thought it went relatively smooth and wanted to offer my experience with this. Thanks to all who wrote there ideas /experiences down, I was able to pull this off. Thanks again for all the preplanning tips! :thmbsp: Mission accomplished! :banana:

LowMan-Steve
08-11-2011, 03:15 PM
I have a set of Qa's and one emit plays sometimes and sometimes not. It starts crackling and going on ang off. When this happens an increase in the volume gets it going again. The other one doesnt play at all, and fuse is good and I messed with the pot by turning it back and forth seveal times and tapping it to no avail. I will check resistance on the non playing one. Any advice on the intermittent one?

mr.jones
08-11-2011, 03:20 PM
Great thread!

What does everyone think of a subforum called: "Repair and Parts"? If there's enough interest, Scott or I can ask the admins to clutter up the server just a little bit more...

Great idea for a subforum.



:bigok:
This thread is a keeper....excellent work on the tweet!

sglight
01-21-2012, 04:52 PM
There are six screws that hold them together that use a cap type of nut with a shallow phillips head. I loosened them before I made a crude fixture out of a 2x10

_Tim
01-25-2014, 08:28 AM
Hi

I've got a pair of qb for a year now, bought them in a second hand shop for 40 euros and I love them. A while later i noticed the tweeters aren't working anymore. Apperently the fuses died, so I looked for replacements, and didn't find any tube fuses of 1.25A so I used a box fuse with same specs.
Now, yesterday I noticed that my tweeters aren't working anymore. I've measured the resistence of my fuses and they were 0 Ohm, so they didn't burned through. I've noticed on the tweeters that some of these 'wires' (don't know how to call them) were loose. Is this repairable? I don't have much knowledge about this subject. Is it possible I clipped my amp, I use a Kenwood ka-4010?
I love my qb's especially with them tweeters.

Thanks

chef free
07-10-2014, 01:00 PM
Tim-
Do you mean that the little silver traces have broken off the mylar plastic? If so you can fix them with some "window defogger repair" products like Loctite 15067.

This is MUCH EASIER if you make a stencil first. Take an index card and a very sharp knife and cut a slot the same width as the trace. Use the stencil to make sure the repair material only touches the trace you are repairing.

Qb's were the first "real" speakers I ever owned, still have them too, they sound pretty darn good!

Qrell
07-12-2014, 05:31 PM
One of my Qa emits was dead, measured and got no reading the good reads 3.2, so after taking apart it looks like somebody was poking a sharp object through the square hole on the faceplate, so there is indents on the track in 4/5 spots, one part looks ripped..if I touch the track diff places I can get a reading 3.2. -Q

Qrell
07-12-2014, 06:02 PM
under magnification.. yea there's small hole/rip that goes through the mylar & 2 tracks.. is this particular emit toast ? -Q

elnaldo
07-14-2014, 05:17 PM
You could try the "window defogger repair" trick. It' about repairing a metal trace.

Read about how to disassemble the emit without damaging it. Those magnets are very strong and will tend to rotate when you loose the screws. The long screws tip is a good one.

AND, THOSE 1.25A FUSES ARE TOO LARGE. IN MY EXPERIENCE, MANY EMITS BURN BEFORE THAT 1.25 A FUSE (WHAT CAN BE CONFIRMED READING THIS THREAD), SO MY SPEAKERS NOW HAVE 0.5A OR 0.75A FUSES.

I PREFER TO REPLACE A FUSE THAN TO REPLACE ONE EMIT (WHAT ALREADY HAPPENED ONCE IN MY LIFE, AND WILL NEVER HAPPEN AGAIN)

chef free
07-15-2014, 04:04 PM
Elnaldo's right about the fuses! I hooked my Qbs up to a 200 watt McIntosh amp and within 10 minutes I had literally blown the metal traces right off the Mylar! No way to fix them! I use 1 amp fast blow fuses with a 100 watt amp now.