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AKG K240 Studio - no sound in left speaker. Replacement? Studio Headphones
Old 3rd July 2011
  #1
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AKG K240 Studio - no sound in left speaker. Replacement?

During a recording session yesterday, the sound in the left speaker on my K240 just died. Even when wobbling the cable around, there is no sound. Could it be that the speaker is blown? The headphones were pushed really loud when it happened, as the vocalist in my band needs som really loud stuff going on to get the feel right.

Is there a point in buying a new cable to check it out? The phones are 4 years old and the earcups are pretty torn, and never really fit my ears well (I have big ears). The only thing I liked about them were the sound.

So I'm thinking of going the Beyerdynamic 770-route for a replacement. Would that be a good idea?
Old 3rd July 2011
  #2
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Capashitor's Avatar
Try to replace the cable/connector first, and check the connection inside the headphones, also try them on other devices, maybe your heapdhones output died. I can hardly imagine 4 year old K240 die just like this, without warning or a testament. I have a 25 years old K141 here, and it seems its going to last forever. But they were built before a certain event that happened to the company in 1993 ...
Old 3rd July 2011
  #3
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we have had 10 pairs of the k240studio hp's going on year 8 and they have been dropping like flies this year, left side cut out usually, i bought 6 new ones...hoping they last at least another 8 years.....

i have a pile of them that i want to take apart and fix. any suggestions?
Old 3rd July 2011
  #4
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Try calling AKG and tell the switchboard person that you need to talk to someone about disassembly. Then that person can tell you how to troubleshoot the phones.

The problem may be a very simple one which you may be able to fix- even if the particular part is broken.

AKG phones (ones with the unique dual headband design) are built/put together in a way that you couldn't imagine without disassembling one. It's hard to describe-the internal electrical contacts are on plastic pieces that are mechanically integral to the tensioned head band design. Over time, they crack. You may be able to fix or otherwise continue with that cracked part-it all depends. Those parts are available from AKG.

The design is either elegant or convoluted-depending on whether you're having problems or not!

My experience with them predates the change the made a couple or more years ago when they revised how the cord enters the phones. Perhaps they re-engineered those plastic terminal blocks at that time-I don't know.

OTH, maybe your problems are more basic, such as a blown driver, an open external wire, or something other than those terminal blocks already mentioned.
Old 3rd July 2011
  #5
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cinealta's Avatar
 

The left headphone always drops out like clockwork. It's the connector/cable. Been happening since the 80s.
Old 3rd July 2011
  #6
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Quote:
Originally Posted by dabigfrog View Post
we have had 10 pairs of the k240studio hp's going on year 8 and they have been dropping like flies this year, left side cut out usually, i bought 6 new ones...hoping they last at least another 8 years.....

i have a pile of them that i want to take apart and fix. any suggestions?
Even if you decide not to fix them, perhaps you can discern exactly what went wrong and then post your findings here.
Old 3rd July 2011
  #7
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Quote:
Originally Posted by cinealta View Post
It's the connector/cable.
Could you be more specific? The connector/cable consists of several external and internal components.
Old 3rd July 2011
  #8
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cinealta's Avatar
 

Quote:
Originally Posted by JEGG View Post
Could you be more specific? The connector/cable consists of several external and internal components.
In the ones I owned, I would fiddle with the connector, or where the wire connects to the connector and the audio would cut in and out. Which made me think that the problem is not in the speaker itself but with the connector or the interface where the connector connects to the wire.

Time was always an issue for me so I never spliced on a new connector to confirm the fix but it's worth a try.
Old 3rd July 2011
  #9
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Rick Sutton's Avatar
 

I have at least a dozen 240 phones in my studio many well over 10 years old (probably closer to 20 years old!).
There are quite a few things that can go wrong but the vast majority of the problems are simple continuity issues. Often the problem can be located by listening to the phones while manipulating the cable very carefully from the connector all the way up to the earcup. If the cable is good then pull the earcup off your head by an inch or so and move it in all the directions it will allow. Often the sound will cut in and out when you move the appropriate part. As in all continuity trouble shooting a small VOM (meter) can be very helpful.
The most common place that the 240's go bad is in the left cup where the cable interfaces with the connections to the drivers. The wiring inside the cup is accessed by prying up the gold medallion to uncover the screw that takes the back cover off. The wiring destined for the left ear is a simple "floating" connection and this often breaks due to the flexing that the headphones take with constant use. The wiring for the right cup is attached to the two steel rods that go through the head strap and then interface in the back of the right cup.
If the wiring has broken at the driver it takes more disassembly to get to the connections.
I keep spare drivers but out of the dozens of times I have been inside the 240's probably only 2 or 3 times have I had to replace a blown unit.
If you do remove the gold medallion you probably need to straighten out the medallion before gluing it back in place. When you glue it remember that you may need to take that medallion off in the future for more repairs so don't use an epoxy or similar glue that will make it impossible to remove. The best glue I have found for this is Ambroid, basically a hobby glue that is like a thin rubber cement.
Old 3rd July 2011
  #10
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Hi Rick thanks for all the help...one thing can you describe the dissasembly 2nd part:

"If the wiring has broken at the driver it takes more disassembly to get to the connections."

how do you remove the gyro plastic clip from the rest to get to the driver?

is there a certain way to squeeze it to get the pegs to pop out or is there another way?
Old 3rd July 2011
  #11
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Quote:
Originally Posted by dabigfrog View Post
Hi Rick thanks for all the help...one thing can you describe the dissasembly 2nd part:

"If the wiring has broken at the driver it takes more disassembly to get to the connections."

how do you remove the gyro plastic clip from the rest to get to the driver?

is there a certain way to squeeze it to get the pegs to pop out or is there another way?
Basically I just muscle it out. Sorry I can't describe it but IIRC I insert the flat side of a screwdriver between the clip and the capsule enclosure, rotate the screwdriver and just pop it out on one side. I vaguely recall that I sometimes do more disassembly than necessary but I so rarely have to go that far inside the 240's that I forget what the essential moves are. I have definitely had to put new wiring to the capsule contacts a few times. One time, the solder tab on one pole of the capsule had sheared off and I had to use an Exacto knife to dig into the plastic to expose enough contact to solder to.
About the only thing (besides a blown capsule) in a 240 that really can get tough to repair without a factory replacement is the plastic assembly that holds the ends of the steel rods in the cup assembly (where the wires to the capsule connect with the external cable). These crack and shatter with use and once that happens the rods move around so much that they constantly break the audio connections. At this point I use epoxy to glue the broken assembly and rods permanently together and hope for the best.
Old 3rd July 2011
  #12
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I needed to go over to the studio so I took a couple of headphones apart to see if i could describe the disassembly better. Guess what? AKG changed the internal construction at least once, probably more, because mine had different internal parts in them from each other.
Anyway I took a couple of pictures of one type where you can access the contacts of the driver to check them and resolder if necessary. The picture on the left shows the two parts that seperate when the copper screw in the middle of the smaller/right assembly is removed. This allows access to the driver for re-soldering if needed.to release the gimbel to replace the driver you can either pry it apart with a small screwdriver or take off the ear cup pads and cloth coverings where you can find two rectangular openings that are the bottom of the posts that hold the gimble mount. Insert a small screwdriver in the hole and CAREFULLY bend the post away from the pin while using your other hand to pull the assembly apart. Doesn't take much effort. Put it back together with same procedure in reverse.
The other set I took apart wont allow for this and here I'd snake the screwdriver into the gimble area and pop it apart.
I'm hoping somebody will read this and tell us all what a dumb procedure this is (although it works) as I'd love to know is there is a "secret handshake" that I could use in the future!
I gotta admit that when I took the 2nd set apart i realized that I had glued it back together so many times over the years for various repairs that if I ever have to put a new driver in that one it will probably be a major pita, if possible at all. Oh well, better than buying new headphones every 18 months or so!
Attached Thumbnails
AKG K240 Studio - no sound in left speaker. Replacement?-240-.jpg   AKG K240 Studio - no sound in left speaker. Replacement?-240-b.jpg  
Old 4th July 2011
  #13
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Quote:
Originally Posted by Rick Sutton View Post
About the only thing (besides a blown capsule) in a 240 that really can get tough to repair without a factory replacement is the plastic assembly that holds the ends of the steel rods in the cup assembly (where the wires to the capsule connect with the external cable). These crack and shatter with use and once that happens the rods move around so much that they constantly break the audio connections. At this point I use epoxy to glue the broken assembly and rods permanently together and hope for the best.
That is what I was trying, ineptly, to mention.

Thanks for your very detailed commentary, and your discovery of later manufacturing modifications.

And thanks for the time in posting the excellent pic's.
Old 4th July 2011
  #14
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From a person who fixes these often.....a bro tip for y'all:

HOw to NOT destroy the "gold medallion" (or silver if they are old enough)

Use a heat gun on a medium setting, fire it right at the medallion for about a minute.

(NOT quite hot enough to melt the plastic) The glue loosens and it can be pried up without bending or damaging the medallion.

Then use whatever glue you want to put them back. It helps if the NEW glue is also melt-able, for example, a hot glue gun works great.

Additional bro tip:

Sometimes you can set the medallion back in place, heat it up, and the original glue will stick again. Press it down in place with a pencil eraser or something similar so you don't burn your fingers.
Old 24th July 2011
  #15
Gear Maniac
 

I have a weird thing going with my old k240's, the "high-ohm" versions (I have two pairs of those, and I really like them over the low-ohm easy driven ones)...

Often the right can dies, but only when I am not using them.. ie. when I plug them in, the right side is, as a rule, dead, but then I plug them in and out a few times, and all of a sudden after 10-15 times, I hear a "crack" in the right side, as there was an electrical circuit cutting in, and they start working again!!

I can fiddle around with the cable as much as I want, it never makes any difference, when finally up and running, there's never any problem and the right can plays normally no matter if I provoke the cable or the connector again...

Weird huh?



Ideas?



D.Don
Old 24th July 2011
  #16
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Rick Sutton's Avatar
 

Quote:
Originally Posted by D.Don View Post
I have a weird thing going with my old k240's, the "high-ohm" versions (I have two pairs of those, and I really like them over the low-ohm easy driven ones)...

Often the right can dies, but only when I am not using them.. ie. when I plug them in, the right side is, as a rule, dead, but then I plug them in and out a few times, and all of a sudden after 10-15 times, I hear a "crack" in the right side, as there was an electrical circuit cutting in, and they start working again!!

I can fiddle around with the cable as much as I want, it never makes any difference, when finally up and running, there's never any problem and the right can plays normally no matter if I provoke the cable or the connector again...

Weird huh?



Ideas?



D.Don
99% of the time the problem is inside the cans not in the cord/cable. If you're lucky it is just a flaky connection (these things flex a lot and connections break or go partial). You need to check in the left can first (where the cable terminates) and see if the connections are good then go to the right can if need be. In my experience most problems are found in the left can even when the right can is the one not working.
Old 24th July 2011
  #17
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Quote:
Originally Posted by Rick Sutton View Post
99% of the time the problem is inside the cans not in the cord/cable. If you're lucky it is just a flaky connection (these things flex a lot and connections break or go partial). You need to check in the left can first (where the cable terminates) and see if the connections are good then go to the right can if need be. In my experience most problems are found in the left can even when the right can is the one not working.
Thanks!

I'll give it a shot! Heatgun was the deal was it?


Old 24th July 2011
  #18
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Quote:
Originally Posted by D.Don View Post
Heatgun was the deal was it?

According to TRJanuary that's the ticket. Mine have been re-glued so many times that I pop out the medallion with a tiny screwdriver but I'm going to try the heatgun next time I find one I haven't re-glued before. (thanks TR!)
Let us know what you find.
Old 24th July 2011
  #19
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Quote:
Originally Posted by Rick Sutton View Post
According to TRJanuary that's the ticket. Mine have been re-glued so many times that I pop out the medallion with a tiny screwdriver but I'm going to try the heatgun next time I find one I haven't re-glued before. (thanks TR!)
Let us know what you find.
All cabling all the way into the actual "speaker" (medallion?) seems to be in perfect condition, no lose solderings or anything else, it all looks afaics, the way it should.

I played around with the idea here this morning that now after I had opened both sides up, maybe things will work fine now. And since the problem only arises occasionally, now I will wait until next time I have a problem with them (for now they work fine again, as they do in periods), and then I may try to open up the medallion...
Old 16th December 2011
  #20
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Does anyone know where I can find a replacement driver/capsule/speaker for the K 240s? I'm seeing nothing in retail vendor stores. Direct from AKG?

Has anyone had to actually replace one before? I would think they would just sell the whole ear basket assembly as the driver is glued and not practical to remove.

EDIT: I now see that the gray driver assembly can be removed from the earpiece. First remove the swivel mount by popping it loose from the end nipples. Carefully pry the driver out by using a screwdriver to push the two end tounge clamps back - be careful not to snap the plastic. Done.

I've owned and unfortunately repaired about 10 pairs of K141s and a couple K240s over the years. The much too (IMO) thin ga wire is prone to breaking either at the metal U bar connector or, worse inside the cable itself. If you own the newer models that use the molded 1/8 in w/ 1/4 adapter you can easily have, and probably eventually will have a faulty connection between the adapter. This was a bad move IMO to do this. The older models had permanent 1/4 in plugs - much easier to repair. Why they chose 1/8 in as the default connector on a set of pro studio phones is a mystery to me. I can understand that on cheaper phones where the target market is different. I often just clipped the 1/8 in plugs off and put 1/4 in on.

Another tip - shop down a higher quality screw for the round cover plate. This is the tiny screw beneath the badge that must be removed to access the wires. This very critical screw also holds the T shaped strain relief in place where the cable connects to the ear basket. On avg I've found this screw to last all of about 4 removal/rescrews before the phillips head grooves strip completely out. Yes, they are of that lousy of quality. Ironically the larger screw right beside it that holds the basket assembly together is big enough to use on 50lb shelving brackets.

This is the first time I've ever seen a blown driver. The previous owner had a habit of listening at extremely loud volumes for long periods of time - bass=10, treble=10, so I'm not really surprised.

Last edited by lassoharp; 16th December 2011 at 06:55 AM.. Reason: correction of facts
Old 13th April 2012
  #21
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Quote:
Originally Posted by lassoharp View Post
The older models had permanent 1/4 in plugs - much easier to repair. Why they chose 1/8 in as the default connector on a set of pro studio phones is a mystery to me. I can understand that on cheaper phones where the target market is different. I often just clipped the 1/8 in plugs off and put 1/4 in on.
Day 1: open the box, unscrew the adapter, place one drop of super glue on the THREADS, screw the adapter back on. No more issues with stolen adapters and we're all good for the studio. 7yrs later I have my first broken 1/4" - and some broken HP spkrs which is why I came to this post - forgot how to open these suckas
Old 18th August 2014
  #22
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Family kitten just chewed through my K240 Monitor cable. Really don't want to have to buy a new pair because this should be a simple fix. I'm ok with soldering.

So, a heatgun to help prose off the medallion and solder a new cable.

Suggestions on where to get a suitable cable? Maybe buy one of those prewired with mini-XLR and snip off the mini-XLR plug?

Or perhaps could I do the "join" where the cable is damaged and save opening up the headphone?
Attached Thumbnails
AKG K240 Studio - no sound in left speaker. Replacement?-win_20140818_143409.jpg  
Old 18th August 2014
  #23
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Maybe I'll just put a mini-XLR where the cable is damaged and buy a replacement cable with mini-xlr to trs jack . Might be easier than cracking open the headphones.
Old 18th August 2014
  #24
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the 10-12 sets of akg 240S over here in the dead pile all have a loose unattached yellow wire inside the ear cup that has broken from the solder making the left side drop out … it is a PITA to get them back together!… we gave up on akg and moved on to shure and sony headphones… no more problems.
Old 29th May 2015
  #25
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I'm having the same problem, left channel drops out but comes in again when cable is jiggled (at the point right where it enters the left phone.) These phones are quite old - at least 10 years - and I really like them - can anyone suggest a competent audio shop that could repair them? I am too clumsy to attempt to open them up and fix the wire. I'd even be willing to send them to AKG, although they will probably charge a fortune. Any help/suggestions appreciated.
Old 29th May 2015
  #26
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Given up on AKG headphones, most shoddily made piece of kit I ever owned.
Old 30th May 2015
  #27
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K240s

12-15 years of problem-free usage is not what I would call "shoddy." However, if you can advise on specifically WHAT phones you think are better, and WHY, do let us all draw upon your esteemed wisdom.

Quote:
Originally Posted by vincentvangogo View Post
Given up on AKG headphones, most shoddily made piece of kit I ever owned.
Old 31st May 2015
  #28
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Quote:
Originally Posted by jduesenb View Post
12-15 years of problem-free usage is not what I would call "shoddy." However, if you can advise on specifically WHAT phones you think are better, and WHY, do let us all draw upon your esteemed wisdom.
Presumably yours were made before they farmed production out to China. The lead on mine is one up from paper. It started falling apart within a few weeks. The plastic casing broke (on both sides) after around three months. Then after about six months the sound went on one side. That's when I decided to invest in a pair of ATH M50x. Maybe not the best pair in the world, but at least they pass audio and I haven't had to hold them together with half a roll of Gaffa tape.
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