Do-it-yourself doorphone repair with metak

In detail: do-it-yourself doorphone repair with metak from a real master for the site my.housecope.com.

Usually, the device of the tubes and their principle of operation on different models are very similar. They usually differ only in design, layout, and functionality.

Please note that the tube has polarity. Therefore, when dismantling it for repair, be sure to sign the incoming wires so as not to confuse the polarity later.

With this problem, until you pull out the tongue, the call will follow constantly, and therefore, it is not possible to open the door.

To eliminate the malfunction, it is necessary to disassemble the tube body. To do this, unscrew the screw, and where the cord is inserted, we open the case. On the front panel, where the door open button and the toggle switch on and off the tube are located, and there is a tongue.

It is held by a bracket, which, during long-term use, is partially straightened, so the tongue can be moved not only forward - backward, but also to the right - to the left. At the same time, it comes out of the engagement of the staple and does not always fall into place when we fix the tube in the holder.

It is quite simple to eliminate this with an ordinary soldering iron, and burrs can be removed with an ordinary office knife.

But first you need to pull out the tongue. To do this, slowly lift it until it rests against the bracket. Now with very little force, gently pull the tongue out. Pull towards yourself first, say the right or left side.

With the tip of the soldering iron tip, touch the surface of the bracket at a distance of about 1 mm and hold it there for about 7 - 10 seconds. Then quickly remove, and with the back of the screwdriver we press on the bracket, bending it. We hold the screwdriver until the plastic hardens.

Video (click to play).

Then you check the pull of the tongue. It should only move freely back and forth.

the cause of this common malfunction is the microswitch located under the open button. (SA1).

The first symptom of emerging problems in the microswitch is crackling and clicking in the speaker when the door open button is pressed.

For dismantling the MP: between the case and the board, we fix the tip of a thin screwdriver, and with a soldering iron we warm up both terminals at the same time. As soon as the solder has melted, we pry the screwdriver and carefully raise the MP, we repeat this procedure with the other two conclusions.

On a new switch, straighten the leads with tweezers before replacing them and be sure to irradiate them. After that, insert the micric into place and solder it. If you are not friends with the basic tool of a radio amateur, I advise you to read the article on how to properly solder.

it is necessary to check the ends "plus" and "minus" following from the intercom panel. If they are intact, then we turn them off.

We disassemble the tube. To do this, unscrew the screw securing the top cover and snap off the plastic latches at the bottom.

Verify that both wires are soldered to the speaker device terminals. Sometimes, due to poor-quality soldering, the wires come off the terminals, this is a very common reason for resetting the call ring. Along the way, we check the integrity of the speaker coil using a multimeter in the dial mode.

We assemble the pipe and test its operation. If the problem persists, go to the next step. This is a switch responsible for turning the intercom handset on and off. Usually, it is located next to the door unlock button.

On the sides of the switch there are latches that fix it to the panel. Use a thin screwdriver to slightly press on the latch, while simultaneously pulling this side. We repeat the same operation on the other side of the switch, and now you can pull it out.

We put a thin screwdriver between the key and the body by 3 - 4 mm. With the end of a screwdriver, gently squeeze out the side of the key until the latch appears. Then, from the opposite side, we do the same, and we already take out the entire key.

We turn the case over and take out the movable contact, and then rinse it with alcohol.

but it’s just strange that the company itself metakom for so long kept silent about the presence of such egregious bugs. For example, I myself actually bought the equipment for the entrance, and the neighbors, thank God, at least paid for the installation and thanks for that. and then I find out that all the homeless people go to my entrance in formation and get ready in places convenient for them, and the intercom has already become like a creative decoration.
so I don't see any more moral excuses for the metakom company - they actually sell master keys to their own panels, buy whoever wants and go wherever you want. I found some interesting information, I think that it may be useful to someone.

the scheme, of course, not from the metacom, but from the visit, but they are exactly the same, since I also parsed the metacom pipe and drew the scheme. I'll look if I'll post it later.
and so from the diagram it is clear that all operations there and back dance on the change in the resistance of the subscriber tube.

when put - the line is actually loaded by a speaker with a strict impedance of 50 ohm
the pipe rises and the conversation part is turned on, since the shunting r3 c1 is removed. the resistance increases a lot, but when the conversation starts, it naturally starts to jump .. in general, just like in a regular telephone line.
now you decided to open the door - they pressed it, kicked the transistor and it closed completely - the intercom realized that the door needed to be opened.
you lay down the pipe and return the 440 ohm impedance shunted by the 50 ohm speaker to the line.
if you are tired of calls, switch the line to one 51 ohm resistor and that's it. there will be no calls and the intercom will know that everything is in order with the handset.

so .. there is a desire to share with everyone some information on the intercom metakom. the question is - will this not be some kind of violation? .. of course I didn’t sketched the diagram of the panel itself, maybe it’s not a grateful and mutronous thing, but in general terms I can tell you how it works, and there’s nothing new about it .. so there are standard chips for which datasheets are in the internet with piping diagrams. however, the code seems to have succeeded in sorting out the information in the PPZ, where all passwords and keys are stored. at the same time, the version about the keys of the "all-terrain vehicles" was confirmed - it was only worth replacing the void in the middle filled with FF codes with any others and voila - not a single all-terrain vehicle works anymore. The only disappointment is that the firmware begins to think that the free space has run out and new keys cannot be hammered in, you need to change the beginning of the empty space to FF again, 4 bytes per key planned for recording.
=====

however, there is still some kind of jumper, in the area of the ATtiny12L-4SI processor (8-bit AVR Microcontroller with 1K Byte Flash), which most likely (99%) performs the function of exchanging with Tochmemori tablets (why is there a processor? )

in general, for today there are several ways (for those who know, let your knowledge remain with you, you don’t want to share, don’t need to.) of course I understand that this topic, as it would not be worth starting at all, maybe silly kids .. read it. be puzzled by the options for illegal actions. etc. however, today it makes no sense to keep silent about it because the intercoms have been compromised .. you know, there is such an expression among signalmen. the keys we had on ribbons like ... punch tapes. we burned them later.

in short, method 1 - replace with a meta or a visit with something more modern, but preferably not on RFID cards - since they start to glitch in the cold, and the RFID card receiver module turned out to be very delicate and cannot stand picking with knives (as it turned out), so there is still a point to love the most reliable option.
there is an option 2 - to insert between the contact and the input of the tochmemori controller -FILTER keys-blanks. this is not a good option for many reasons.
but the third option is to replace the flashed processor with a more recent version (today there is version 1.3, but it was 1.0), which completely closes all the holes.
and of course there is an option - filling the empty space with the FF code with any other code. or not a full fill, but only 4 bytes at the beginning of an empty space and, if necessary, enter the key number manually using a compact programmer right on the spot near the entrance door - this is the cheapest option. for comparison, a microcontroller chip flashed with a new firmware costs 250 rubles. "Filter" costs about 400 rubles.
[/ q]

anyone else interested - a small photo addition to the general overview of the doorphone call panel metakom.
In addition, I would like to advise the developers of this miracle (if they read the forum) to eliminate weak points in the design, although progress is already visible - on the new panels there is a more vandal-resistant speaker grill (the old one was just the top of the mudstroi), however, as before, it is not sealed and with the usual act of vandalism like “the intercom is drinking beer too”, the panel will bend.

Image - Do-it-yourself doorphone repair with metak

Thank you very much for yourself now.
found one cant change the master code (in 24c64 in the editor) to any other (three times) 1F88-1F98 and the master code becomes 1234 regardless of the one set in 24c64

but you need to either change a bunch of intercoms or somehow try to serve the master codes and the master tablet WARNING!

WARNING! the current password is visible there but does not change (it is written and compared somewhere else) for any changes again 1234. but I have not yet checked how the piece of hardware works on a real object after that (and I have master keys there - apparently WARNING! either reset all keys or default)

You cannot change data (passwords) directly in memory, the piece of iron goes crazy (although it seems to work on the table), you can only look at the passwords and then through its keyboard. quarrel, I'll go to bed.

something did not drive. why change the password directly in the editor? Well, you found it out, use it.
Besides, hasn't everyone forgot that the firmware is checked by the processor and if the checksum does not match, then it seems that it is overwritten to the state of a freshly made panel.

but! I confirm once again that after replacing the FF codes in the entire space of the “empty” memory area (the space reserved for new keys) with any other code (directly from the “pony prog” program editor), the intercom starts normally, including in the entrance already connected to the entrance system condition. that is, the method WORKS.
I will say even more - if after changing the FF code, add the key or key codes (4 bytes per key) - the intercom also starts normally and works properly. in this way, several intercoms in my city have already been fixed. nobody complains.
and if there is a need to get one more key, then everything is easily solved by copying any key to the same “all-terrain-blank” key made in metakom. so that all the wolves are safe and the sheep are fed. Amen.

ps. the method can be recommended as a panacea for the ubiquitous all-terrain vehicles.
for implementation, you need two people with a laptop with a COM port + programmer. and of course you need a "key-secret" to remove the panel.
attention - before removing the flash drive, do not forget to turn off the power by unscrewing the AC18v clamp. just pull out one of the wires.
ps. however, do not be greedy and buy a processor with a new firmware (version 1.03) - it will be a much more stable and flexible option.

... or a variant using memory tablets (Dallas 1996) with a volume of exactly 64kbits (8192bytes), that is, as much as a flash drive in the 24c64 panel
The point is that - directly at the company, in the warmth and comfort, we open the dump file of the flash drive from such a house, such an entrance.
change the white space code to any other value. we are saved.
then we fill in the dump into the key "Dallas1996" and repeat all the entrances in turn.
further on the object - we enter the reading mode "1996" and voila. "All-terrain vehicles" no longer pass.
if the company does not have the equipment for working with keys "1996", then you can use one of the old panels that are lying around in many companies.
everything is simple, we only need an electronics board from the panel -
We take out the 24c64 flash drive from the electronics board from the socket, insert it into the programmer and use the "pony prog" program to change the void code. stitching back. we take it out of the programmer and insert it into the intercom panel. then we take “1996” and with the help of several clicks on the intercom buttons we fill in the dump into the memory of “1996”. then we go to the required entrance and fill in the dump from “1996” into it. all. repeat this number of times.

Dear forum users and moderators! I propose to open a branch for the repair of these particular panels! There are questions and suggestions! Well, are we opening it or are we writing here?

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In modern porches, special talking devices are most often installed as a gateway. They allow you to preserve your safety and the safety of your property.Connecting the intercom Vizit (Visit), Falcon Eye, Commax (Kommax) and Metakom is most often performed by special service companies, but this can be done with your own hands.An intercom is a device that allows someone to enter a room, or vice versa, to deny entry, without direct contact with him. The device has gained particular popularity literally in the last decade; previously, combination locks were most often used to protect front doors. Image - Do-it-yourself doorphone repair with metak

Photo - system design

An intercom in an apartment or a private house consists of a handset, a door station, video equipment (if additional connection for monitoring a door or a gate is required), a lock and a switch. Consider functions of every detail:

As an additional protection to the call, the ability to connect a video intercom (Kenwei KW-4HPTN, Kocom KCV-A374SD) can also be added. In this case, all data is transmitted using the camera on a special TV or computer. In contrast to the audio intercom, the video system is more reliable in use, because in addition to the call, visual control of visitors is also carried out.

Photo - wiring diagram of the video intercom

There are several types of intercoms that are used to protect against uninvited guests of an apartment or private building. Depending on the type, their connection differs:

Digital (Eplutus EP-2297C, Gardi GRD, Hyundai HA-201);
Coordinate matrix (AVC-305, Commax CDV-DPV-43 MTN, Laskomex).

Digital They work according to the following principle: when they call, they transmit a signal over a two-wire line, in which the number of the connected apartment is recognized. In this case, so-called jumpers are used for pairing, which transmit signals to a specific tube over a twisted mesh. Each tube, in turn, is equipped with microcircuits. It is very convenient that all apartments can be connected to such a controller not only in the entrance, but also on a specific floor.

Intercom connection diagram coordinate-matrix type more simple reliable, therefore it is more popular. A switch is connected to the coordinating communication device, which, when called, switches the signal to a specific tube. The connection is made using wires of tens and units, that is, each apartment is designated by two cables, the numbers of which are not repeated. To establish communication, a signal is sent over the DAT1 line to the switch. After that, the modulator transforms and processes the information received and connects to one specific "Unit" and one "Ten". Then, thanks to an electromagnetic relay, a connection is made to a specific apartment via the LIN telephone line.

Photo - wiring diagram of the digital model

Most often, such a connection is parallel, which greatly facilitates self-installation. The only thing to remember is about the polarity of the door station of the intercom, electric lock and tube of the apartment. If the electrical connection is made incorrectly, then the work of not only a specific subscriber, but also the entire security system is disrupted.

Photo - intercom control unit

Installation rules for intercoms VIZIT

Step-by-step instructions on how to independently connect an Eltis, Cyfral (Digital) video intercom with a z 5r controller:

This controller can be connected to a key reader (touch memory) or a buzzer, a button that will be used to open an electromechanical lock, a backlight, the lock itself and a power supply;

The buzzer and door sensor are optional parts, while the entire system depends on the door release button and power supply. If necessary, the screen is also installed; optical control can be carried out through the monitor;

To connect the board, a terminal block is most often used, to the contacts of which the necessary network wires are connected;

After that, simply connect all the necessary wires to the apartment tube and check the correct polarity.

Also, domestic models of intercoms are very popular, in particular, this is KS-2006. To connect them, circuits with two switches, one connection module, for several subscribers, etc. can be used.What to do if the Factorial, Eltis intercom is disconnected from the power supply:

A twisted pair of wires is most often installed in an apartment panel. To find it, you need to open the flap where the Urmet, Tsifral, Factorial, etc. intercom cable was connected to the driveway or door lock;

Photo - marking of wires when connected

After that, determine which wires are responsible for tens, and which for units. This can be done by looking at similar cables on adjacent connections;

Be sure to watch the polarity;

When connecting the intercom of the cottage, it will be enough just to polarly connect the cables of the switch and the unlocking lock.

Prices for the repair or installation of intercom systems may vary depending on the city and the specific company. On average, the price of connecting an intercom varies between 200-500 rubles (the cost is indicated only for work, without a price list for spent wires). For example, connecting the MVK-325 UKP outdoor panel in Moscow and St. Petersburg will cost 500 rubles.

The intercom often has various kinds of problems. Intercom malfunctions are usually associated with the operation of the subscriber's handset. Troubleshooting sometimes requires the involvement of experts in order not to damage the system. Individual breakdowns may be eliminated independently.

The cause of the breakdown is improper operation, non-observance of recommendations, timely maintenance of equipment. Minor repairs of intercoms are often carried out, since a small malfunction leads to dysfunction of the device over time.

Intercom brings convenience to life until malfunctions

poor contact and power supply to the device;
malfunction of the controller;
worn keys;
faulty power supply.

It is possible to determine why the intercom does not work empirically. Use a multimeter to check. To fix the detected breakdowns, you may need a soldering iron and practical skills in repairing electrical equipment.

The first way to identify a malfunction is by visual inspection. It is not difficult to determine by eye the detail that may have caused the system malfunction: broken or bare wires, broken / missing buttons on the calling panel. The cost and complexity of adjustment depends on the severity of the damage. It may require a partial change of parts, installation of a suitable device for operation.

A multimeter will help identify problems in the wires

Does the intercom stop responding to pressing the keys, applying the key to the reader on the door? It is recommended to check the power supply to the device. If you have experienced short interruptions in operation in the past, it is most likely that the power supply has been interrupted. Ignoring the problem led to a complete lack of electricity.

A common malfunction is an inoperative element in the tube. To correct the situation, it is required to inspect and repair the intercom tube.

One of the likely open-circuit locations is the switch wire. The breakdown is easy to repair yourself. If there are no visible signal breaks, but the switch is suspected of a malfunction, the masters should do the check.

Attention! If the intercom does not work, where to call? It is recommended that you contact the company that installed the device. The company's foremen are repairing intercom tubes.

A malfunction is possible due to incorrect commutation, complete lack of communication between the external panel on the door and the subscriber. The reason for the subscriber's handset is a frequent breakdown. If the scheme is coordinate, on the switchboard, they check the buses under the symbols "E" and "D", which are responsible for units and tens, check each pair for subscriber handsets.The standard resistance of devices is in the segment between 600 and 800 Ohms in one direction, and in the other there is no final value. If any tube does not meet the specified resistance values, it is the cause of the system breakdown. The repair consists in correcting the polarity, eliminating the short circuit.

There are the following prerequisites for checking the power supply:

the call panel gives a quiet signal sound;
the tone stopped working;
poor performance of the electromagnetic lock.

The signal is interrupted at times and the speakers produce a quiet sound

Typically, systems use two channels of power supply, rated at 12 and 18 volts, from a power supply that is installed to the electronic devices and to the electromagnetic lock. First of all, it is recommended to pay attention to the fuses. Defective ones will need to be replaced. Replacing the unit in case of a breakdown is trusted by the master, it is difficult to do the work on your own without damaging the system.

If no external damage is found on the device, a broken cable may be the culprit. The cables are checked with the same tester.

Sometimes video intercoms also stop working. This indicates a malfunction of the camcorder or a loss of signal. To check the operability, the camera is connected directly to the internal panel. If everything is in order, the cause of the breakdown is the wire.

Intercom broken? What breakdowns are found in the tube of the device, how to fix them? Here are the common types of breakdowns.

It happens that when you press the button for the remote admission of the visitor, communication with him from the apartment is lost. The conversation is interrupted, but the button does not open the door. The cause of the malfunction is a damaged wire. How to fix an intercom? We'll have to remove the case, check the soldering around the tube speaker. If a broken wire is found, it will need to be soldered back into place, not forgetting about the polarity. A more rare case is a breakage and damage to the speaker wires. Visually, such a breakdown cannot be determined; you will have to use a tester. Some models allow you to turn off the speaker volume if the apartment owners do not want to be disturbed. This function sometimes causes breakage due to poor / dirty contact.

Important! Replacing the elements of the doorphone must be carried out taking into account the polarity. Image - Do-it-yourself doorphone repair with metak

The condition of the cable is checked with a tester.

The normal call rejection mode is carried out when the intercom receiver is hung up without pressing the door lock opening button. A special switch is responsible for the function. This is usually a tongue holder. To solve the problem, it is recommended to replace the part.

The number is dialed from the door station of the doorphone, but the call is not made. The problem arises if the installation does not take into account the polarity of the connection. To remedy the situation, you will need to find a wire in the intercom switch, which is responsible for connecting the external panel and the tube, swap the minus and plus wires.

In the event of such a malfunction, it is recommended to pay attention to the speaker and microphone of the handset. Perhaps they were the cause of everything. Sometimes the sound is quiet due to insufficient contact. It is necessary to check how the connector sits on the intercom handset. If it dangles, it is recommended to try to twitch it while talking. Have a glimpse of normal sounding? So it's worth making a connection.

Repairing an intercom is not such a difficult task if you know the procedure

There are many reasons for intercom breakdowns in an apartment. Do-it-yourself intercom repair is sometimes difficult. You should not indulge your vanity by refusing the help of specialists. Call the company that carried out the installation, give your home address, apartment number. Perhaps they will remotely detect the malfunction. Otherwise, the masters will come and fix everything as soon as possible. If the owner pays for the intercom, then he pays for maintenance and repairs. So why should he repair the intercom himself?

"Metacom" is a well-known domestic brand of intercoms, standing on the same level with "Visit", but by 2015 it began to lose its relevance in the market, having existed on it since 1996.

There are probably many reasons for this: from the deliberate complication of software circuits to obsolete functionality. Nevertheless, this brand still exists on the market and has its users, and therefore the codes from this system have not disappeared from the minds of people (and the Internet - even more so). Mostly these intercom systems work with contact keys.

As you know, situations can occur when the key to the intercom is broken, and it is necessary to go inside the house. To open the device without a key, codes and the intercom service menu come to the rescue. Specifically, the Metakom brand has the following algorithm of actions:

The combination is introduced 65535, call;
Is typed number 1234 and another call is made, after number 9 is entered (for some brands, you do not need to enter a nine);

Press the bell key on the calling panel;
Enter the serial number of the first apartment;
Call, and after the appearance of the inscription "Cod" enter the code 5702 (sometimes - 1234, 4568, etc.).
To remove keys from memory, use a combination of commands 65535, Call, 1234, Call, 990111.
Order may work to open the door. "Call - 27 - Call - 5702".

However, instead of selecting codes and adapting to a specific calling system, it is better to use a universal master key. It can be passed off as a duplicate created on the emulator, or an outdated way of assigning an empty cell code to a key.

Why? Because no preventive and corrective work was carried out in this area. Apparently, the level of competence and responsibility for their products is not as high as stated on the official website of the developer.

We open the "Metakom" intercom with a display

Perhaps, "Metacom" intercoms are not as widely known as "Visit", but advanced users, obviously, will not be able to get lost in the complicated engineering menu of this company. And if not thanks to my knowledge and experience, then at least thanks to this article.Control and monitoring systems for the admission of people to residential buildings have been popular among the population for a relatively long time. During this time, many apartment owners at least once, but faced problems with the failure of this equipment when opening the door.In the article on the operation of the intercom system, we analyzed the principles of the design of the intercom. Now you can move on to a more interesting and important practical part of this issue: self-repair of the intercom tube with your own hands.Often it can be solved by calling the master at home, when the problem is caused by a malfunction of the equipment of the intercom system of the entrance:

there is no call from the intercom in the apartment;

the equipment does not respond to the ringing device signals;

the wrong subscriber is being called;

and other similar defects.

But there is another type of breakdowns, on which we will dwell in more detail - malfunctions in the intercom tube itself.Each manufacturer of intercom handsets operating on coordinate matrix communication lines (Cyfral, Eltis, Vizit or any other) distinguishes their products with design and functionality.In the simplest case, a subscriber receiver can only have a button for remote opening of an electronic lock on a door with an intercom. Depending on the model, it is upgraded by adding:

LED indication;

adjusting the tone and (or) volume of the call signal;

mute button;

the ability to connect a second tube.

By design and principle of operation, all models of subscriber intercom handsets are very similar. Therefore, we will describe the malfunctions using the example of a subscriber tube Tsifral KL-2.If you disassemble the intercom tube, you can see that its "filling" is quite simple: a small electronic board, a button, some wires, a reed switch, a microphone, a speaker ... and a lot of free space. Image - Do-it-yourself doorphone repair with metak

The schematic diagram of the digital KL-2 intercom tube is shown in the picture.

In it, the places of frequent damage are already highlighted with a color spot - contacts:

Consider possible breakdowns inside the tube.

Usually all defects are reduced to:

mechanical damage to the base body or tube;
failure of electrical circuit elements.

The intercom handset has a plastic case, designed for long-term operation. But, in almost all models there is one weak point - its holder. True, in some devices it performs only the function of a "hook" to hold its weight on the base, while in others an additional tongue is installed, which includes a communication chain.

In all cases, a soldering iron will help us out. With its help, it is necessary to warm up the broken off piece of plastic and "solder" it to the place of damage to the case.

When turning on the intercom tube is tied to the mechanics of the tongue, and not to the reed microswitch, you will have to solder the plastic more carefully so as not to create additional damage - to break this very mechanics. Otherwise, the circuit may turn out to be either permanently turned off, or vice versa, turned on and will not be able to work normally.

To perform this operation, certain specific knowledge is not required, it is enough just to be able to work with a soldering iron.

Likewise, you can solder the plastic parts inside the tube holding the internal parts, if necessary.

But this is unlikely - during operation, only the tongue holder and the doorphone door open button are exposed to mechanical stress.

When we get a call to the intercom, the call goes, and we pick up the phone, specify who came to us, press the door open button, but ... the door does not open (or does not always work the first time).

Here, most likely, the SB1 microswitch located under the button will be to blame.

To eliminate the malfunction, first of all we remove the doorphone cover and carefully examine the place where the button is attached - "mikrika":

if it is installed separately from the board, then it is worth checking the reliability of the soldering of the wires to its contacts - all of a sudden, a wire breakage at its leg has simply occurred;
when it is securely soldered to the PCB, there is a high likelihood of breakage of the switch itself.

To make sure that it is the microswitch that is to blame, you can temporarily solder the wires in its place with any known working switch that is at hand or without it at all. The main thing is that for the duration of the check they could simulate the operation of the button - close and open the door opening circuit.

The repair is reduced to soldering the disconnected wire or replacing the clock button, which you can buy at any radio parts store.

While providing access to the visitor by pressing the corresponding button on the handset, instead of opening, the call from the subscriber is dropped, and the door remains closed. In case of such a malfunction, you should check the integrity of the wires and the quality of their soldering near the speaker.

If you visually notice a soldered wire, you should solder it in place. The polarity of the connection of the wires in this case is important.

In rare situations, an open or broken wire in the speaker coil may cause a problem. But this malfunction cannot be visually determined - you will have to ring the circuit with a tester or multimeter.

Some models, including our Tsifral KL-2, are equipped with a speaker switch, which allows you to turn off the sound signal when you call. This can be useful if you do not want to be disturbed by a late guest with a wrong number, or if you wake up a small child who has fallen asleep during the day.

So, worn out or dirty contacts of the button of this switch can also affect the reset of the connection instead of opening the door, be the cause of this breakdown.

In normal mode, the call is dropped when we put the receiver on the base without pressing the door lock open button. Accordingly, a switch is responsible for resetting (disconnecting the circuit): either a reed switch or one located under the tongue holder. It all depends on the tube model.

The most reliable way to solve this breakdown is to replace the failed switch.

The indicated reason may appear immediately after the installation of the intercom tube in the apartment, if the polarity is reversed when connecting the wires.

Often, ordinary telephone "noodles" in which both ends do not differ from each other act as a trunk wire leading into an apartment.

At the point where the base is connected to the mains, there are usually plus and minus markings, but it is better to mark the wire yourself.

If you do not observe the polarity, then immediately after dialing the number, instead of the ringing sound of the subscriber, a reset will be made. Accordingly, none of the guests, due to a breakdown of the intercom, will not be able to give an audible call signal to your handset.

Here it is worth paying attention to the speaker and microphone located in the intercom receiver. Perhaps they are the reason for poor audibility.

Inside the tube, on the printed circuit board, there may be a trimming resistor (it is absent in the Tsifral KL-2 model), which is directly related to adjusting the balance of the microphone and speaker. Just don't use it right away for customization. Better to remember the initial position of the slider, and then scroll it to one side and the other a couple of times. After this operation, return it to its original state.

This will restore good contact on the resistor and possibly eliminate any poor audibility on the tube.

Radio amateurs can also replace the capacitors located on the board next to the trimmer.

So we have sorted out all the main malfunctions of the intercom tube for opening the door, which you can fix yourself.

If you have a handset from an old and unnecessary phone with an ordinary battery, then in five minutes you can assemble an intercom or intercom with your own hands.

The owner of the video Evseenko Technology demonstrates this process in his video.

Video (click to play).

If you still have questions about DIY handset repair, you can ask them in the comments. And now it is convenient for you to share the article with your friends on social networks.