Do-it-yourself doorphone repair with metak

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 opener 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 the ringing reset. 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 stick 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]

who else is 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.

Thank you very much now I understand
Founded 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 iron works on a real object after that (and I have master keys there - apparently WARNING! either reset all keys or default)

You can't 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 even say 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, the same 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 here, 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. 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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