How to fix a speaker with your own hands. Repairing the speaker

Speaker breakdowns and methods for eliminating them

Symptoms of malfunction	Treatment methods
1. Doesn't play at all (no sound)	The coil is burnt out or the wire is broken. Probably due to high power overload. Disassembling and rewinding the voice coil
2. The mobile system does not play and is destroyed mechanical damage	In such cases, serious repairs are required.
3. The speaker (I apologize for the precision of the wording) “farts”	There may be several options here: A) The supply wires are broken and therefore they spark, hence the sound... Repair – It is normal to repair flexible leads. b) But the centering of the coil may be disturbed and, with a large amplitude, the coil touches the core (or flange). This is where there is no clear solution... If, indeed, the alignment is disturbed, then you can paste over the centering washer and glue it again, after first removing the cap and inserting the gasket into the gap. c) the defect may be caused not due to a misalignment, but due to deformation of the coil; due to the speaker being overloaded with high power, the coil may lose round shape and become oval. Then no amount of alignment will help. You need to disassemble the speaker and rewind the coil
4. If the speaker doesn’t “fart”, but “grinds”	In principle, this is the same as step 3, but the effect is less pronounced
5. Extraneous sounds, but not constant, but only occasionally	Probably dirt got into the gap (sawdust, for example) Disassemble the speaker and clean the gap...
6. Rattling sound, constant and throughout the entire frequency range	Delamination of voice coil turns. Disassembling and rewinding the reel
7. The same rattling sound, but only at one frequency (usually from 100 Hz to 1 kHz), something like resonance	Something came loose in the moving system. It is necessary to check the adhesive joints on the cap, on the suspension, on the centering washer. And glue it, of course
8. “Sniffling” or whistling sounds at high amplitude	This is “noise” from air passing through the narrow gap gaps and into the holes on the diffuser, sealed with a cloth in the Riga speaker 75GDN-1. This cannot be cured, it is a design defect. By the way, this is not the case in 75GDN-3, because... there is a hole in the core to equalize pressure (and there are no holes in the diffuser sealed with a rag)
9. Yes, still... If he farts, but not constantly	The coil came unglued from the diffuser... Glue the coil to the diffuser

Repair for a slipped coil turn.

Unsolder first flexible liner, then saturate the gasket and suspension (corrugation and lower centering washer made of fabric) of the diffuser along the diameter in the place where it is glued to the diffuser holder (siluminum or steel basket) with solvent 646-648 (the solvent sometimes does not soften the glue, you can try xylene, toluene, benzene),
and wait for the glue to soften (from 10 to 20 minutes), when you can easily move the glued surface with your finger on the corrugation and the centering washer from the silumin diffuser holder. Carefully (DO NOT TEAR IT OFF! EVERYTHING SHOULD PULL AWAY BY ITSELF, otherwise you just poured too little solvent or waited too long) remove the diffuser from the diffuser holder. Place the coils coil by coil in place and secure thin layer BF-2 glue (it is possible, but worse, to use nitro glue) in particularly powerful heads, the coil is impregnated with a thin layer of epoxy glue. Reassemble in reverse order, generously moistening all surfaces with solvent, thereby soaking old glue again, put the diffuser in place, after centering the coil in the gap, begin gluing - pressing the fabric of the centering washer and the rubber (foam rubber - depending on the design of the head) corrugation to the silumin (steel) surface of the diffuser holder in its proper place. Center using rolled up film (for powerful heads, you can use rectangular pieces of thick cardboard, evenly distributed along the diameter of the gap, long enough for them to be easily removed from the gap after assembling the head), inserted into the gap of the core and voice coil (the cap for this is taken from the diffuser first carefully peel off, pouring solvent over the adhesive seam - make sure that the solvent does not get under the cap, otherwise the voice coil frame may peel off from the throat of the diffuser (This is exactly what happened to me: approx. Serzhi). When assembling, do not forget about the presence of a flexible connection to the coil, and do not glue past the coincidence of the coil terminals with the terminals on the diffuser holder. Using the same method, glue the gasket around the perimeter of the diffuser into place on top of the corrugation.

If there is a shortage of glue applied at the factory during assembly, glue STRICTLY with nitro glue such as Moment or Phoenix (those in large tubes) during assembly. This guarantees the ability to disassemble the head again for repairs, or in case of incorrect assembly (my old glue did not want to stick - I carefully dissolved and removed it and applied a thin layer of new one).
You need to pour a lot of solvent so that it stands and flows in the adhesive joints. You can slowly pour directly from the neck of the bottle (preferably, of course, from an oil can, which is made of chemical-resistant plastic). The solvent is toxic, don't poison yourself! He strongly rushes to the toilet after inhaling it - apparently his kidneys immediately remove the poison. Work in a ventilated place!
Protect the adhesive joints of the magnetic system itself and the center of the diffuser under the cap (glued voice coil frame) from solvent penetration, otherwise the head will fall apart. constituent elements. Apply only to the perimeter of the diffuser; carefully moisten the centering washer with a generously soaked cotton swab.

The main thing is CAREFULNESS! You can ruin everything, the paper is still there, crumple the coil frame and tear and crumple the diffuser, crumple and tear the cap.

In general, VERY GENTLE AND CAREFUL!

It is never necessary to unstick the magnetic system itself and it is unacceptable - the sensitivity (recoil) of the head may drop after gluing it again. For this reason, they are not always achieved good results in the repair of heads with a unglued magnetic system. You can glue a magnet to a core, but the magnetic force in the gap may decrease.

Rewinding a burnt out voice coil.

Carefully wind the burnt coil from the frame (if it doesn’t wind well, drop a drop of solvent), to facilitate winding and prevent the frame from collapsing, make a mandrel, which is discussed below. When winding, sketch where the beginning of the old coil was and how the terminals were sealed. Count the turns of the old coil. (Or look at the information on the speakers on this site. If it is not there yet, it will be soon :)) Select the wire exactly according to the diameter (you can measure it with a micrometer, and if you don’t have one, then wind 10 turns of wire on a suitable rod, measure the width of 10 turns with a caliper, and divide by 10) and carefully, turn to turn, wind it on a mandrel tightly inserted into the coil frame. The mandrel is made from a slightly larger piece of metal pipe (it’s better not too thick - it won’t compress) with a longitudinal cut, so that when the mandrel is inserted into the frame, the pipe can be compressed, and then it will straighten out and press the frame tightly from the inside. You can make a cut in the pipe with a hacksaw. Take the pipe of such length that it is convenient to squeeze the free end when putting the frame on it. Wind the first turn according to the beginning of winding the old coil (as a rule, the first turn is located at the neck of the diffuser and is soldered directly to the contact rivet). Secure the first turn with thread, which is removed after winding. When winding, sometimes rotate the diffuser with the coil on the mandrel to prevent the frame from sticking on the mandrel. The tension during winding is not strong - otherwise you can compress the frame together with the mandrel (for this reason, it is sometimes useful to wedge a split mandrel from the inside by inserting a suitable wire into the cut or a hard object inside the pipe). When winding, you impregnate the first layer with liquid glue - an extremely thin layer. Handle the wire gently, otherwise you may tear off the varnish insulation. After winding the coil, saturate it (in a thin layer) with liquid glue BF-2 - diluted with alcohol (epoxy - diluted with nitro solvent 646-648), tin the leads with rosin and solder them to the contact rivets. When soldering, the use of acid and acid-containing fluxes is unacceptable, only rosin!

How to try to straighten a jammed cap.

Try to peel it off carefully - generously watering the gluing perimeter with nitro solvent 646-648 (or another - see above). After peeling off, lightly moisten it with water and firmly clamp it in a vice, selecting a punch and a matrix of a suitable convex shape for it. (my finger just straightened out - it was dented a little) After several days of exposure in a vice, process inner side very liquid epoxy glue diluted with nitro solvent - a very thin layer!
Wait until it sets completely (liquefied epoxy can take more than 3 days to dry), then carefully glue it in place with “MOMENT” type nitro glue - the one that comes in large tubes.
Although in theory, such a head should of course be replaced with a new one.
When pressing the cap on the tweeter or midrange, you can try to stick tape on it and quickly pull it towards you. Must straighten up.

How to remove metal filings from a magnetic gap.

Very often, when disassembling heads, a large amount of metal filings and pieces of magnet are found in their magnetic gaps. They are removed by holding a piece of adhesive tape (insulating tape) in the gap, folded in half, with the sticky layer facing out. Some experts recommend pouring rubber glue into the gap, and after it dries, pull it out of the gap along with the sawdust. I haven’t tried it myself, and I can say that this method is most likely not suitable for many gaps in which there are free cavities between the ring magnet and the core washer and the diffuser holder flange (almost all low-frequency and high-power broadband heads with a ferrite-barium ring magnet). For those heads in which there are no such cavities, and the gap is an even longitudinal slot in depth, this method is probably possible.

A little trick.

If the coil touches, sometimes this is due to the diffuser sagging downwards due to the old age of the head. Then you can try to change its position in the column - turn the bottom of the speaker up 180 degrees in the column panel. Then if the coil has not flown off, but is simply touching it due to the diffuser sagging over time, then the sagging may be compensated.
Sometimes a hitting coil can be cured by creating an opposite distortion of the diffuser using an insert into the diffuser holder (rag, foam rubber). Leave the head in this position for several weeks, and perhaps the misalignment after removing the insert will be compensated.
Unfortunately, these tricks rarely help, and you have to disassemble the head.

The principle of the electrodynamic GG device is shown in Fig. 1.

Fig 1. The device of the electrodynamic head of the loudspeaker / - diffuser holder, 2 - movable system 1, 3-magnetic circuit

The loudspeaker head consists of three main parts - a magnetic circuit 3, a moving system 2 and a diffuser holder 1.
The magnetic circuit of the GG can be made in two versions: shielded or unshielded, depending on the requirements for the equipment in which the GG is used. Various options shielded core, ring with cast magnets and ring with additional shield and unshielded circuits are shown in Fig. 2.

Fig 2. Design of the magnetic circuit of the loudspeaker head a - shielded circuit with a core magnet, b - unshielded circuit with a ring magnet, c - circuit with a ring magnet and an external screen, 1 - core, 2 - upper flange, 3 - permanent magnet, 4 - lower flange ( or glass), 5 - screen, 6 - tip

The magnetic circuit of the GG consists of elements of the magnetic circuit of the upper flange 2, cup 4, core 1 and permanent magnet 3 with tip 6 (Fig. 2.a) or the upper and lower flanges 2 and 4, core 1 and permanent magnet 3 (Fig. 2 , b). Sometimes it is placed in a shielding glass (Fig. 2,c). The constant magnetic flux created by the magnet using magnetic flanges and the core is directed into the air working gap, which has the form of an annular cylindrical slot between the core and the upper flange
Ring ferrite-barium magnets (25BA170, 28RA180) are usually used as permanent magnets in unshielded circuits; in shielded ones, cast cobalt-containing (YN13DK24) or rare-earth magnets are used. For the manufacture of magnetic circuit parts, mild electrical or structural steel is usually used (Art. 10)
The efficiency of the GG as an electromechanical transducer is characterized by the product of the magnetic field induction in the gap and the length of the conductor (i.e., the length of the voice coil wire). The magnitude of the induction and the structure of the magnetic field distribution are affected by the width and height of the working gap, the configuration of the flanges and core, as well as the volume and width of permanent magnet.

Fig 3. Design of the moving head system
loudspeaker a - with a conical diffuser, b - with a dome diaphragm,
1- voice coil 2-centering washer, 3 - flexible leads, 4 -
suspension, 5 - diffuser (diaphragm), 6 - dust cap

Figure 3 shows the mobile GG system. It includes suspension 4, cone diffuser or dome diaphragm 5, centering washer 2, dust cap 6, voice coil 1, flexible leads 3.
Suspension 4 has the form of a corrugated annular shell, which has great flexibility in the axial direction, which allows the diffuser to perform axial vibrations with a large displacement amplitude. The suspension is cast together with the diaphragm from paper pulp or made from special soft materials(rubber, polyurethane foam, etc.)
The diaphragm (diffuser) 5 is an elastic shell of rotation (conical, dome or flat), which oscillates under the action of an axial mechanical force from the coil, exciting vibrations in the air environment and emitting sound. Currently, most GGs use diffusers made of natural cellulose materials with a successful combination physical and mechanical parameters. IN last years used as materials for diaphragms (diffusers) are polymer, honeycomb, metal and composite materials.
Centering washer 2 is a corrugated membrane that ensures centering of the voice coil in the gap, prevents the occurrence of circular vibrations, allowing the diaphragm to make large displacements in the axial direction. Centering washers are usually made of cotton fabric, cambric or chiffon, impregnated with bakelite varnish.
Dust cap 6 is a dome or flat membrane that protects the gap from dust, acting as an additional stiffener on the diaphragm. It is usually made from paper pulp, fabric or metal foil.
Voice coil 1 is a cylindrical frame with an insulated conductor wound in several layers. As a rule, the number of layers of the voice coil is even, so that its leads come out in one direction. When an alternating current magnetic circuit flows through a voice coil placed in a radial cylindrical gap, it will be affected by mechanical force, under the influence of which vibrations of the voice coil and the associated diaphragm occur. The coil frame is usually made of cable paper or metal foil; copper or aluminum wire in enamel insulation is used as a conductor.
Flexible leads 3 connect the voice coil conductor to the output connecting terminals GG.
The diffuser holder serves to connect the magnetic circuit, the moving GG system and provides fastening in the housing of the equipment where it is used. The diffuser holder is usually made by stamping from steel or by casting from silumin.
All elements of the moving system and magnetic circuit have a significant impact on the electroacoustic characteristics and sound quality of the GG.

Disassembling and assembling the speaker

First, the patient's flexible lead wires were unsoldered (from the side of the contact pads)

	Then, with a solvent (646 or any other capable of dissolving glue, such as “Moment”), using a syringe with a needle, the place where the dust cap and diffuser were glued together (around the perimeter) was moistened...
	Place where the centering washer is glued to the diffuser (along the perimeter)...
	And the place where the diffuser itself is glued to the diffuser holder basket (again around the perimeter) The speaker was left in this state for about 15 minutes with periodic repetition of the previous three steps (as the solvent was absorbed/evaporated)
Attention! When working with solvent, you should observe safety precautions - avoid contact with skin (work with rubber gloves!) and mucous membranes! Don't eat or smoke! Work in a well-ventilated area! When wet - use a small amount solvent, avoiding getting it into the place where the coil and centering washer are glued!
	Depending on the type of solvent and air temperature, after 10-15 minutes of the above operations, using a sharp object, you can carefully pry up the dust cap and remove it. The cap should either come off very easily or offer very little resistance. If you need to apply significant force, repeat the operation by wetting its edges with solvent and waiting!
	After peeling off the cap, carefully pour out the remaining solvent from the recess near the coil mandrel (by turning the patient over).
	By this time the centering washer has time to come off. Carefully, without any effort, separate it from the diffuser holder basket. if necessary, re-wet the gluing area with solvent.
	We wet the place where the diffuser is glued to the diffuser holder. We wait... We wet it again and wait again... After 10 minutes you can try to peel off the diffuser. Ideally, it should effortlessly separate from the diffuser holder (along with the coil and centering washer). But sometimes he needs a little help (the main thing is to be careful! Do not damage the rubber suspension!!!)
	We clean the gluing areas from old glue and dry the disassembled speaker.
	We examine the disassembled patient to determine if there is a malfunction. Let's look at the reel. If there are no abrasions or loose threads on it, we leave it alone. When a thread comes off, glue it back with a thin layer of BF-2 glue.
	We carefully inspect the place where the supply wires are attached to the diffuser. So it is - the patient has the most common malfunction found in old speakers with a large diffuser stroke. The supply wire at the attachment point is frayed/broken. What kind of contact can we talk about when everything hangs on a thread running through the center! Carefully bend the copper “tendrils”... And unsolder the supply wire. We repeat the operation for the second transaction (even if he is still alive - the disease is easier to prevent!) We cut off the supply wires at the break point...
	And we tin the resulting ends (of course, we first use rosin). Care is required here! Use a small amount of low-melting solder - the solder is absorbed into the wiring like a sponge! Carefully solder the wiring into place, bend the copper “tendrils” and glue it with glue (Moment, BF-2) where the wiring connects to the diffuser. Let us remember - you cannot solder wires to the fastening “antennae”! Otherwise, how can the wiring be changed again in ten years? ;),
	Assembling the speaker. We place the diffuser with all the “equipment” in the diffuser holder, orienting the wiring to the places where they are attached. Then we check the correct polarity - when connecting a 1.5V AA battery to the terminals, when connecting the “+” battery to the “+” speaker, the diffuser will “jump” out of the basket. We place the diffuser so that its “+” supply wire is at the “+” mark on the speaker basket.
	We solder the lead wires to the contact pads. Please note that the length of the wires has decreased by almost half a centimeter. Therefore, we solder them not as it was at the factory - to the hole in the plate, but with a minimum margin, to preserve the length.
	We center the diffuser in its basket using photographic film (or thick paper), which we place in the gap between the core and the coil. The main rule is to place the centering evenly around the perimeter to maintain the same gap. The amount (or thickness) of centering should be such that when the diffuser is slightly protruded outward, it will freely rest on it and not fall inward. For the 25GDN-1-4 speaker, 4 pieces of photographic film, placed in pairs in front of each other, are enough for this. The length of the photographic film should be such that it does not interfere if you place the speaker on the diffuser. For what - read below.
Glue the diffuser. We use the indication for the glue used (I recommend “Moment”, main criterion choice so that the glue can later be dissolved with a solvent). I usually stick the diffuser 1-1.5 cm up so that the centering washer does not touch the diffuser holder basket, then I apply a thin layer of glue to it and the basket with a brush, wait and firmly push the diffuser inside, additionally pressing the washer to the basket around the perimeter using my fingers . Then I glue the diffuser (in the retracted state, avoiding distortion). We leave the speaker upside down for several hours under a load (this is why our photographic film should not protrude beyond the plane of the diffuser!)...
Then we check the speaker for correct assembly. We take out the centering and carefully check the movement of the diffuser with our fingers. It should walk easily, without making overtones (there should be no touching of the coil and the core!). We connect the speaker to the amplifier and feed it low-frequency tones at a low volume. There should be no extraneous sounds. If the gluing is incorrect (misalignment, etc.), the speaker must be unstuck (see above) and reassembled, being careful! With high-quality assembly, 99% of the time we will get a fully working speaker.
	We coat the edge of the dust cap with glue, wait and carefully glue it to the diffuser. Care and precision are required here - a crookedly glued cap does not affect the sound quality, but it greatly spoils appearance dynamics. When gluing, do not press on the center of the cap!!! This may cause it to bend and you will have to peel it off, straighten it, coat the inside with a thin layer of epoxy for strength and glue it back.
	We wait until all the parts are completely glued together (about a day) and put the finished speaker in its place. We enjoy the sound, which is no worse than that of a new factory similar speaker.

That's it, now you see that fixing the speaker is an easy task. The main thing is slowness and accuracy! So, in an hour, you can leisurely repair almost any woofer or midrange speaker, domestic or imported (for gluing up imported speakers, a more powerful solvent is often required, such as acetone or toluene, be careful - they are poisonous!!!) that has a similar defect.

Yes, after the operation, the former patient got his second wind and the cheerful yellow subs continue to do their hard bass work.

Previously, we have already addressed the topic of repairing car dynamic heads or, simply put, repairing a speaker with your own hands. Then we considered a method of restoring the head suspension using ordinary silicone. But we also encounter problems of a more serious nature. That is why today we decided to focus on such a common problem as misalignment.

Naturally, today everyone knows what a dynamic head consists of. Yes, it contains a signal electric type is converted into membrane movement and spreads through the air.

At the time when the same signal is focused on the coil, a magnetic field is formed that interacts with the magnet. And due to the fact that this signal is temporary, the coil begins to vibrate, as if running away from the field. However, the coil has nowhere to run and begins to transmit this signal to the diffuser, which in turn transmits it into the air, producing sound. Naturally, this process is transferred in simple words, and he's on technical terms will sound completely different. But the essence itself is important.

An iron core is used here to direct the field. In turn, this core is attached to a permanent magnet. It is a round disc-type iron platform with a sleeve in the center, which consists of a voice coil. In order for this coil to move easily, there is a special gap in the middle of the magnet and the core. And due to some unfavorable factors, the glue that connects the disk to the magnet weakens and the core crushes the coil, which leads to immobility of the diffuser. The speakers may work, but you won't be able to hear any bass.

How to get out of this difficult situation? And is it possible to make the speakers return to their normal state? This is exactly what will be discussed later in the article. So, in the situation that I encountered, the speaker mount was broken, and because of this, I immediately started with the centering washer. It happens that in speakers the same centering washer is attached with very weak glue.

Therefore, in order to separate the washer, you just need to moisten the junction of the chassis with it with simple acetone and wait a couple of seconds. And in some cases, acetone alone is not enough. Most often this concerns high-quality speakers, where strong and high-quality glue is used to attach the washer and chassis. Here you need to resort to real vandalism. Namely, it is necessary stationery knife cut off the washer and wires coming from the voice coil towards the speakers. Next you need to disconnect the diffuser.

At the end of these manipulations, it becomes clear that the core sticks to the magnet and needs to be put in its place, namely in the center. However, it is worth noting that this is not at all easy to do, because here you need to work with iron and a permanent magnet.

They interact extremely reliably with each other, and it will be difficult for you to place the core in the center. It is important to understand that the voice coil is completely attached to the diffuser and is crushed. Therefore, you need to tighten the diffuser itself. After freeing the coil, you need to carefully inspect it.

If the varnish that covers its wire is damaged or the coil itself is dented, additional reconstruction of the coil is also required.

To repair the coil, the first thing you need to do is look for metal sheets, the thickness of which is half a centimeter.

These sheets need to be attached between the core and the magnet. In general, we need to fill all the space that the coil occupies.
In this case, each plate must be inserted evenly so that the distance is equal on each side.

After all this, you need to glue the magnet to the washer holding the core itself. Best to use for this good glue by type of moment.

You can also take epoxy for these purposes, but here you need to mix it with sawdust or pieces of fabric for greater reliability.

Then, after the glue has hardened, you can remove all the plates and put the entire speaker back together.

The suspension and centering washer sit on the same glue. In this case, it is also possible to additionally repair the suspension.

In this way, you can repair heads of various types.

And I also want to note one point: if you decide to sell your car and don’t know where to start, just call the Center-Auto company, which will buy your car. Even if it is after an accident, contact and receive money on the same day.

I like the old big, heavy speakers that were popular in the 90s. Despite their advanced age, they still sound pretty good and produce good bass. Recently I came across a pair of these speakers in a deplorable condition, but I decided to restore them and bring them back to life.

Professional repair of such speakers is very expensive, so it’s quite work equipment often they simply throw it away and buy modern subwoofers that are compact in size.

Will need

For proper repair Rubber or any other elastic gaskets of suitable diameter will be required. To accurately calculate right size spacers, you need to measure the outer diameter of the cardboard cone and the inner diameter of the steel frame, and based on this, look for spacers of the required diameter.

Restoration work

I recorded the entire speaker repair process with a camera. Below is a detailed photo report of all steps.
The first step after removing the front panel is to remove the old seal and glue from the speaker circumference. To do this, I used a flat, sharp blade, but this must be done carefully so as not to damage the cardboard cone.

To center the cone while gluing it, you need access to the steel core. In large speakers, it is covered with a cardboard plug (it is glued), which must be carefully removed without damaging the cone. With cardboard plugs I managed to pry them off sharp knife, after which they came off along the adhesive connection, since they were not glued very tightly.

In small speakers, the dust caps turned out to be tightly glued, so they had to be carefully cut in a circle.

The next step is to accurately center the cone relative to the steel core. The free space between the cone and the core turned out to be different in each of the speakers. As an insulator and a kind of winding, I used strips of ordinary paper, which I pushed into the gap around the core until I achieved the most dense filling.

One of the small speakers required only one and a half turns of paper around the core, resulting in a slight displacement of the cone. Fortunately, in my case this circumstance did not affect the performance of the speaker, but I think that it would have been necessary to take thinner paper to complete two full turns.
For gluing rubber or foam seals, any household glue is suitable, for example, PVA or any similar one, which becomes transparent after drying. Glue is applied to the cone and speaker body along the edge of the hole, after which the gasket is carefully applied. You need to smooth it to the surface for a tighter fit and remove excess glue so as not to disturb the centering.

Once the glue has completely dried, you can remove the paper cup wrapped around the core. To check that the cone is properly balanced, lightly press it with your hand: it should vibrate freely without touching the steel core. If friction is present, all centering work should be redone and a new seal should be glued.

Now you need to install new damper pads around the speakers so that the front panel does not press or contact them. By the way, you can use old gaskets, completely free of glue, if they are in normal (not deformed) condition. The damper pad is glued to any glue. If the inner diameter of the new gasket is slightly smaller and covers rubber compressor(this may create interference), then it needs to be trimmed a little along the inner circumference so that the cone vibrates freely.

To glue the dust caps in place, I did the following:

I glued a narrow and folded strip of tape to each cap. The result is a convenient loop so that you can move the semicircular part.
I smeared the edges of the cap with glue.
Carefully placed the cap in its place and applied a little pressure until the glue set.

The current state of the market with loudspeaker prices makes speaker repair virtually unnecessary, but if difficulties arise in purchasing a new speaker to replace a broken or damaged one, then it makes sense to try to restore the damaged loudspeaker with your own hands. I got a few speaker systems coaxial type from various cars. Unfortunately, 2/3 of the speakers produce a distorted signal during playback, and the rest simply do not work. Below we will present material only on the restoration of “junk” car speakers of the coaxial type for future use in the construction or installation in multi-way stationary speaker systems. Before starting work we will carry out diagnostics speaker state.

Diagnostics of the speaker condition

1. Check for debris. Coaxial-type speakers are not completely protected from foreign objects getting into the magnetic gap, this is especially dangerous for old cars with rust or cars that have been used body repair. Checking is simple - carefully with your fingers let's move diffuser into the magnetic system, if you can clearly hear extraneous sounds: rustling, crackling, grinding noises, this means that metal debris may have gotten into the magnetic gap.

2. Take a tester and check the coil resistance in ohmmeter mode. If there is resistance, then this is our case. If there is no resistance, then it makes sense to check the thick flexible copper conductors from the speaker terminals to the diffuser for breaks. If there is no break, then most likely there is a break in the speaker coil and this is the case self-repair not discussed in this article. Instructions for self-repair are given below.

We disassemble and clean the dynamic head with our own hands

1. Unsolder the flexible coil leads from the contact petals for connecting the speaker and the contact petals of the coaxial speaker.

2. Remove coaxial speakers. The manufacturer does not provide for repair of the speaker system and coaxial speakers are installed tightly. The column with reinforced high-frequency speakers was removed by drilling aluminum rivets. We work carefully, the main thing is not to tear or damage anything.

3. On speaker repair forums, methods for dismantling the diffuser and centering washer are given. I also followed this path. We carry out work on outdoors in the absence of open flame sources! After using 100 ml of acetone, it was impossible to peel off the diffuser and washer. The solvent quickly evaporated without softening the adhesive joint. In order to save time and solvent, a strand of cotton fabric was placed at the gluing site and moistened with acetone; if necessary, wetting continued as it evaporated until the glue softened. After softening, use a thin screwdriver to pry up the edge of the centering washer and lift it above the gluing area. The thin rubber diffuser corrugation must be handled more carefully and delicately so as not to damage the rubber.

4. Remove the diffuser. Damage to the insulation of the speaker coil is noticeable from debris that has gotten inside the magnetic system. It is useful to look at the degree of damage under a magnifying glass for the presence of short-circuited turns (scratches to a depth of more than 40% of the diameter of the coil wire); if there is a suspicion of short-circuited turns, then it is better to reject the speaker. Using a damp cloth, I cleaned the diffuser, centering washer and coil inside and out from dirt. Cleaning must be done carefully so as not to damage the coil.

Coil damage

5. The gap in the magnetic system is a sad sight. A strong magnet firmly holds small metal debris and dust. Tried to clean mechanically, but the small size of the gap and its curvature did not allow the debris to be successfully removed. I decided to use a strong stream of air from air compressor – Failed to clear the gap! I had to use another remedy - use a stream of water high pressure from car wash. The result is that I’m all wet, but the gap is 100% cleared, and at the same time the entire frame is shining like new. I tried to do this carefully, since the pressure of the water jet is very high and I admit that if you are particularly zealous, you can destroy the adhesive of the magnet of the speaker system. To prevent rust, you must immediately dry the frame and magnet. After drying, it is useful to check the cleanliness of the gap under a magnifying glass. And as experience has shown, it’s a good idea to seal the gap with tape to protect it from accidental metal debris.

Assembling the speaker

1. After cleaning and drying components dynamics we assemble the structure. It's important not to rush. The goal is to position the coil in the magnetic system exactly in the center and ensure there is clearance and does not touch the coil. From a strip of A4 office paper, 10cm wide and about 18cm long, we roll up a cylinder and insert it inside the diffuser coil. The cylinder should fit snugly against the spool and have no protrusions or bulges inside.
2. Let's try to insert such a structure into a magnetic system. Do not hurry! It's better to practice several times. The cylinder should descend to the entire depth of the magnetic gap and at the same time the coil should hardly move along the inserted cylinder. If the coil moves along the cylinder with great effort, then it is necessary to shorten the length of the paper strip, and if the coil moves freely, then it is necessary to increase the length of the paper strip.

The coil moves tightly in the cylinder
How to repair a speaker yourself? FAQ Part 1

This is the first part of the loudspeaker repair manual.

Here you will find information about the terminology used, speaker problems and the simple repair when only replacement of flexible leads is required. Other issues will be discussed in future articles.

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How does the dynamic head work?

The schematic drawing shows a cross-section of the speaker. This is roughly how low-frequency and mid-frequency loudspeaker heads are designed.

Suspension (corrugated).
Flexible output (pigtail).
Bracket (secures the braid to the diffuser).
Damper (protects the pigtail from breaking near the terminal).
Hole in the housing for flexible output.
Insulating strip (holds the terminal).
Terminal.
Solders connecting the flexible lead to the terminal and the coil lead.
Coil output.
Coil.
Speaker housing (basket, frame).
Diffuser (membrane, diaphragm).
Dust cap (plug).
Centering washer.
Sleeve.
Pole piece.
Kern.
Top flange.
Magnet.
Bottom flange.

The letters N and S indicate Northern and South poles magnet. This is the usual arrangement of the poles, although the opposite occurs occasionally.

In the next picture conventional drawing HF dynamics sectional view.

Coil output.
Insulating gasket.
Suspension (elastic extension of the dome).
Diffuser of dome design (membrane, diaphragm).

The main difference between tweeters and midrange and bass drivers is the absence of a centering washer.

In addition, many HF heads use a dome-shaped diffuser, often called a membrane. The dome and surround of such speakers are a single unit, and the sleeve is attached to the dome.

Since the stroke of the tweeter cone is small, the coil leads often play the role of flexible leads.

What are the types of speaker malfunctions?

Speaker malfunctions occur due to improper use, improper assembly, or normal wear and tear.

Incorrect operation.

Most often, damage occurs due to excess power supplied to the speaker. One of the reasons for such errors may be confusion with the method for determining the power of the speaker and amplifier. This is due to the fact that the same numerical values Effective, root mean square (RMS), or as it is also called, sinusoidal power and amplitude or musical power create a current in the speaker coil that differs by a factor of two.

Another reason that causes speaker overload is the careless redistribution of power between the heads of multi-way speakers. Most often, tweeters - tweeters - suffer from this. The fact is that the power of tweeters in multi-band systems can be less than 10% of the total speaker power. And if the user, using an equalizer, supplies most of the amplifier's power to the tweeter, then the death of the latter can be instantaneous.

There are also mechanical damages to the dust cap, suspension and diffuser. Sometimes these damages lead to misalignment, which in turn leads to the destruction of the coil and sleeve.

Destruction of the sleeve and coil can also be caused by displacement of the core. In such cases, the sleeve along with the coil gets jammed in the magnetic gap. This usually occurs as a result of a loudspeaker or speaker being dropped.

Unskilled assembly.

Due to unskilled assembly, the sleeve, coil, suspension or centering washer may come off. Poor quality gluing can also cause extraneous sounds.

Incorrect fastening flexible leads can significantly reduce their service life.

Normal wear and tear.

If the loudspeaker head is assembled well, the suspension and flexible leads suffer the most as a result of normal wear and tear. The diffuser can also collapse if its safety factor does not match the power of the speaker.

How to identify a faulty speaker element without disassembling?

All speaker malfunctions can be divided into “mechanical” and “electrical”. However, some electrical defects are very difficult to distinguish from mechanical defects by ear.

If no external changes, such as destruction of the corrugation or diffuser, are detected, but extraneous sounds appear in the form of crackling or periodic loss of sound occurs, then you should first check the flexible leads.

To do this, connect a dial ohmmeter to the speaker terminals and move the pigtails while the diffuser is stationary. If the ohmmeter needle moves, it means the flexible lead is damaged.

Other electrical defects include coil breakage and short-circuiting of part of the coil turns or the entire coil. These defects can also be detected using an ohmmeter.


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To do this, a master oscillator signal is supplied to the amplifier input.

A partially peeled off coil or part of the turns can be identified by smoothly changing the frequency of the generator or turning on the generator in the GKCh (Swinging Frequency Generator) mode.

When testing this speaker, the frequency range 20Hz...2kHz with a period of 3 seconds was used. In this speaker, apparently, a significant part of the coil has come unstuck, as overtones are heard over a wide frequency range. If a small fragment of the coil peels off from the sleeve, overtones can appear only at a certain frequency, and only when the damaged structural element enters resonance.

In some cases, to identify a malfunction, it is useful to use an infra-low frequency generator. This can help identify, for example, defects in the gluing of the rubber corrugation to the diffuser. The arrow shows the place where the oversound is formed.


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Rubbing the sleeve against the core or the coil against inner surface The upper flange can also be bent at a frequency of several hertz if you lightly press the corrugation waves with your fingers.

More serious damage to the speakers is even easier to detect.

So, for example, if something is heard when turning the speaker over, it means that part of the turns or the entire coil has fallen off the sleeve.

If the diffuser moves very poorly, then most likely the coil has fallen off and jammed the sleeve in the magnetic gap.

If the diffuser does not move at all, then the core may have moved and jammed the coil along with the sleeve.

Never attempt to disassemble such a speaker without first removing the sleeve, as this may also damage the cone.

How to replace speaker flex leads?

Use extreme caution when replacing flexible leads on an unassembled speaker, as a steel tool attracted by the magnetic system may damage the cone and dust cap.

If access to the flexible terminals (pigtails) of the speaker is free, then you can try to replace them without disassembling the speaker. But, in some cases, the speaker will still have to be disassembled. The picture shows a broken flexible lead.

Old flexible leads should be removed with the utmost care so as not to damage the diffuser or break the coil leads.

First, unbend the brass bracket that holds the flexible terminal, if there is one, of course.

Then the soldering area is heated with a soldering iron to separate both the flexible lead and the coil lead from the diffuser. Usually, after warming up, the glue softens and the leads can be removed.

How can I replace damaged flexible leads?

Of course, the simplest solution is to borrow flexible leads from another speaker of similar power or order from suppliers that sell spare parts for speakers. But, if this is not possible, or you want to save on spare parts, then you can make surrogate braids yourself.

The first and simpler option is to replace the failed pigtail with a piece of MGTF wire of a suitable cross-section. I don’t know who first came up with this, but it was with these flexible terminals that the once popular 4A32 speakers went on sale.

Another option is to make braids from a Soviet-made flexible telephone cable. It can still be found among all the junk at flea markets.

I am familiar with two types of such cable. In one, each wire consists of seven cores, and in the other of fourteen. Each core is made by winding copper tape onto a Mylar thread. In cross-section, the tape has the shape of a rectangle with dimensions of 0.03 x 0.3 mm.

0,03 * 0,3 * 14 = 0,126 (mm²)

As you can see, the cross-section is small, so for powerful speakers you can twist two or more stranded wires.

First, a section or sections of telephone cable are prepared using a soldering iron.

The insulation is removed in small sections to avoid damage to the cores.

Then the cores of each stranded wire are untwisted and twisted again into one wire.

And finally, the flexible lead is carefully glued twice with rubber or 88 glue with an interval of 20 minutes.

Before the first gluing, the twist must be free so that the glue penetrates between the cores. Immediately after the first gluing, the strands are twisted to the end. The second gluing finally fixes the cores relative to each other.

Thus, it is possible to make a flexible lead for a speaker of any power.

If there is no telephone or MGTF wire, then as a temporary measure you can use MGShV wire or even a braid from a shielded wire, but such pigtails do not last long, and they put a greater load on the diffuser due to less flexibility.

When installing a flexible output, you need to take into account that the weakest points of this unit are the places where the pigtail is attached to the diffuser and terminal.

If the fastening brackets are damaged or lost, the braid is secured with two crossed stitches of thread. Then the attachment point is glued with glue with a large dry residue. Weathered BF-2/BF-4 will do.

To prevent premature fracture of the pigtail, the attachment points are covered with several layers of rubber or 88 glue with a transition to a flexible terminal.