In detail: do-it-yourself video surveillance recorder repair from a real master for the site my.housecope.com.
For many car enthusiasts, the DVR is the device that helps in resolving disputes on the road.
Unfortunately, the mass production of DVRs affects their quality and reliability.
The most common malfunctions of DVRs are mechanical breakdowns of connectors and connectors. Failure of electronic components can also occur due to excessive heat from hot sunlight, for example, in summer.
It is also worth noting that each dash cam contains a small lithium battery. And, as you know, excessive heating of a lithium battery can lead to its explosion or "swelling".
To begin with, let's take a look “under the hood” of an ordinary DVR, get acquainted with its electronic stuffing.
Take a video recorder as an example for study. xDevice Black Box-29.
To open the case of the xDevice Black Box-29 DVR, you need a thin Phillips screwdriver. As it turned out, it is rather difficult to find a suitable one. You can use a universal screwdriver to open cell phone cases.
This DVR is equipped with two video cameras. The one that serves for recording the car interior is rigidly fixed to the printed circuit board. There are 2 infrared LEDs on the sides. They are necessary for the background illumination of an object in the absence of lighting.
The camera, which is used to record what is happening on the road, is mounted on a small printed circuit board and installed in a rotatable plastic case.
A flexible ribbon cable connects it to the main PCB. It is perforated - slots are made between the conductors. Thanks to this, the camera module can be rotated 270 0.
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On the printed circuit board, you can find a light sensor - a photoresistor.
A lithium battery is used as a backup power source. Its capacity is small, judging by its size, about 300 - 400 mA / h. It is not the main one - the DVR is powered from a 12v / 24v - 5.5v (2A) converter, which is connected to the cigarette lighter.
The lithium battery serves as a kind of buffer that powers the device during a short power outage of the DVR.
A color LCD board is connected to the main board via a flexible cable.
The core of the device is 3 microcircuits. Unfortunately, for some reason their markings are overwritten. The marking is clearly distinguishable only on the case of the SDRAM memory chip (elixir N2SV12816FS-6K) with a volume of 64Mb.
Also on the printed circuit board you can find peripheral microcircuits: voltage converters, low-power AF amplifier, EEPROM memory.
In addition, there is a microcircuit that is very similar to a 3-axis accelerometer microcircuit.
Apparently, it is she who performs the function G-sensor... Thanks to the G-sensor, modern video recorders can record accelerations, impacts, sudden braking, rotation. Such data can be useful when analyzing an accident.
A microphone and a miniature speaker are also connected to the printed circuit board.
Now let's talk about repairing the xDevice Black Box-29 DVR. As already mentioned, mechanical breakdown of connectors is a common case for such devices. Due to the “cold” soldering of this DVR, the mini USB connector simply fell off. Moreover, it just crumbled.
It would seem that for a person who is familiar with electronics, such a breakdown is a trifling matter. In fact, replacing such a connector is a very troublesome task. All due to the fact that a 10-pin (10 pin) connector.This connector is universal due to the increased number of contacts. For example, some DVRs are equipped with a special cord. miniUSB - RCAwhich allows you to connect the DVR directly to your TV.
Typically a standard USB connector has 4 pins. Two of them supply power (+ and -) 5 volts, and the remaining 2 transmit data. Connector mini USB 5 pin has 1 more contact, which is connected to the common wire (GND).
In connector mini USB 10 pin 10 contacts are already being mounted. The distance between the contacts of such a connector is very small, and it is rather difficult to solder it onto the PCB when replacing it. Not only that, finding a 10 pin connector is more difficult than the widespread 5 pin mini USB connector.
Therefore, in some cases, it makes sense to solder mini USB 5 pin instead of a faulty mini USB 10 pin. The main task of such a repair is to connect the power contacts "+" and "-" in order to ensure the possibility of charging the built-in battery and power supply of the DVR. You can also solder the data pins of the USB connector. This should be done if the set with the DVR comes with a mini USB - USB cable for connecting to a computer.
The rest of the contacts that go to the 10 pin mini USB connector on the printed circuit board can be shortened with a knife so that they do not interfere. Naturally, when making such a replacement, it should be borne in mind that after replacing the USB connector, some functions of the DVR may not be available.
A few words about the power converter.
The power converter of the xDevice Black Box-29 DVR is connected to the standard cigarette lighter (12V) of the car, and to the DVR - a cord with a miniUSB plug.
The converter is implemented on a microcircuit LSP5502... The circuit itself is designed for an input voltage of 12v / 24v and is capable of delivering 5.5v (2A) at the output.
5v converter output circuit protected by suppressor P6KE6.8A... In the event of an abnormal situation and failure of the converter, the P6KE6.8A suppressor will limit the voltage surge that is dangerous for the DVR circuit.
An ordinary fuse is also installed in the charger.
Here is a typical circuit for turning on the LSP5502 in buck DC / DC converter mode. The circuit is taken from the datasheet on the LSP5502.
If there is a need to power the DVR in a workshop (from a 220V network), then it makes sense to temporarily unsolder the connecting power cord from the converter and solder it to a standard charger with a 5-volt output. So, for example, I did.
Repair of video surveillance systems: external manifestations of malfunctions, causes and remedies
Despite the seeming complexity of a video surveillance system, malfunctions only occur in three main elements: cameras, DVRs and the cable network.
The most common causes of equipment breakdowns: violation of the temperature regime, excess of the permissible humidity level, installation errors.
Also, quite often systems do not work due to non-compliance with key operational requirements, improper cabling.
Doesn't give an image, even a background image, doesn't respond to requests. Burned control boards, physical breakage or damage to power cables may be the cause. The problem is solved by replacing the damaged parts.
The camera is loaded with the internal menu displayed on the monitor, but there is no image. Burnout of the CCD matrix. If this part is a candy bar with a sensor board, then replacement is not difficult.
Loads, listens to control, but there is no image, and the menu does not appear. In most cases, this is a breakdown along the transmitting circuits of the video output. The reason could be interference and large voltage surges from the operation of powerful equipment (electric welding, etc.). Board replacement required.
When choosing a video intercom model for an apartment building, first of all, you need to decide what kind of picture you want to get - color or black and white.
There is a criterion by which the comparison and selection of video cameras is made - the "viewing angle", but for rotary devices, the focal length is more important. Read more about PTZ cameras here.
The image is received, the menu is loaded and tested, the PTZ device is not controlled.Burnout of the control board on port 485, as a rule, due to interference in the ungrounded twisted pair. Control board replacement required.
Unstable operation, expressed in periodic shutdown and reboot, in the presence of a PTZ drive, control does not obey. A hardware malfunction is possible - overheating of the microcircuits. Software malfunction - a failure in the firmware or version mismatch with the control program.
It is recommended to reinstall the camera to another location (perhaps it is mounted above a heating device or air conditioner), flashing with the transition to the current version. ATTENTION take the firmware only from the manufacturer's website.
After starting the test, it hangs, then gives an error. When starting the camera, many models perform an autotest of the device; the composition of the testing program depends on a specific model and manufacturer. As a rule, in the passport for the device there is a plate of error codes and the proposed actions to eliminate them. But errors can also be caused by external causes.
- wear of the gear wheel of the rotary device;
- contamination of the rotation control sensor;
- failure in the logic block program.
The mechanical parts should be replaced, the camera firmware should be updated.
DVR does not load... First of all, you need to check the correctness of the connection to the mains, there may be a malfunction of the power button or HDD disk, the control panel of the device. Software reasons - incorrect device firmware update.
The video recorder turns off by itself... Unstable power supply, lost contact of the hard disk cable, sticking of the power button, dust pollution and, as a result, overheating of the processor.
The system does not see the HDD... The disk itself is faulty, the ribbon cable is damaged or lost contact, the SATA port on the board does not work. In some cases, it helps to simply plug the loop.
No camera image on output... Firmware incompatibility between cameras and DVR, too weak signal, incorrect screen settings, incorrect privacy zone setting.
There is a distortion of the color format when viewed in real time. Incorrect monitor settings, too far distance to the camera, incorrect NTSC and PAL settings for BNC output.
Video distortion when viewing archived records. Low write standard selected, file read error, write error due to loop damage.
Most of the malfunctions associated with the DVR are corrected by a banal system reboot. In this case, do not forget to clean and check the contacts inside the device at least 2 times a year.
Cable networks are the main cause of video surveillance malfunctions.
Influence of radio interference
Of the entire spectrum of radio emission, high-frequency waves can have the greatest impact. Electromagnetic disturbances in signal transmission lines can be caused by nearby powerful radio and television transmitters, radars, microwave emitting equipment and other emitting equipment.
Such interference appears in the form of image distortion, stripes and lines on the screen.
Lightning effect
Lead to massive burnout of ungrounded equipment. Standard protection systems for buildings and structures - lightning rods are not designed to protect data transmission lines and electronic devices.
Compulsory grounding of shielded cables and devices is required. In accordance with the technical requirements, the grounding of all network elements must be at one point.
Stray currents in grounding
When performing installation work, especially in multi-channel systems, grounding rules are often ignored. This is sometimes technically impossible to accomplish, especially when using cheap cameras where the BNC connector is not isolated from the case.
The body of such a device itself is grounded to the corresponding contact of the flying plug, which has a grounding terminal. In fact, grid zero is used instead of a ground bus.Accordingly, several such points are formed in the video surveillance system.
Dips and overvoltage in power networks
They are caused not only by the low quality of power grids, but also by periodic daily fluctuations. Peaks of fluctuations occur in the morning and evening, the highest level of overvoltage at night.
Phase imbalance and neutral overload are a less common cause of overvoltage in networks associated with errors in wiring.
Periodic and single impulse noise:
- switching on and off lighting and climatic equipment that consumes a large amount of electricity;
- turning on and off devices and devices with a high level of inductance: starters, transformers, operation of electric welding equipment, etc. etc.
- accidents and short circuits in low-voltage circuits with subsequent operation of the RCD;
- the influence of inductive interference from the operation of urban electric transport.
With the correct installation of the network and the selection of devices, the repair and maintenance of video surveillance systems will require much less financial and labor costs.
Power supplies supply energy to 4-5 devices, no more. The reserve of the rated power supply must be at least 1.4 times greater than the actual consumption. A separate power line must be connected to each chamber.
It should be borne in mind that for some models of external cameras, the secondary internal source is not always galvanically isolated from the camera body. Count the power consumption of all possible devices at a remote video surveillance point: thermocouples, lighting, rotary devices.
Avoid using twists when connecting wires in outdoor power lines, or whole boxes, or adapters in junction boxes. As a last resort, be sure to use heat shrink tubing.
When attaching the camcorder to a conductive surface, be sure to install an insulating pad. Do not ground the camera body to a random metal structure, only use dedicated ground straps.
Video intercom for giving CDV-72BE Commax, which has a 7-inch TFT color screen. Has built-in memory for 128 frames with high resolution.
Before purchasing a touchscreen videophone, you need to decide on the diagonal of its screen. its size is the main dimension of the device. Read more about choosing a touchscreen video intercom in this article.
Before connecting the camera to the DVR, it is necessary to check the potential difference on the device cases. When using BNC connectors, a difference of 35-40V may burn out the output circuits of the camcorder.
The use of normalizing amplifiers is possible not only in long lines, but also to improve the clarity and brightness of the image in ordinary ones.
As a rule, the maintenance agreement does not include a condition for expanding the video surveillance system, but the use of DVRs with a large number of ports will greatly facilitate the scaling of the video surveillance system and reduce its costs.
Every year more and more cars are equipped with video recorders. These devices continuously record on the road and can fix the culprit of an accident or identify a violator of traffic rules. Like any other technique, they periodically fail. In the event of a breakdown, you can try to repair the device yourself, and in some cases, do-it-yourself repairs are not at all difficult.
Despite the fact that products from different manufacturers are on sale, most DVRs have a similar design. In the event of a breakdown, the repair methods are practically the same. Of the most common malfunctions, the following are worth noting.
Fault: The device starts beeping and tries to turn on the recording mode. After a few seconds, a reset occurs and the situation repeats. It appears on the models DVR-227, DVR-F500.
Solution: The cause of the problem lies in the micro SD card adapter.Even if you format the USB stick, the problem will reappear after a couple of days. A new adapter must be installed on the instrument.
Fault: When the recorder is connected to the cigarette lighter, recording does not start, the device is constantly in standby mode. This problem is rare.
Solution: As in the previous case, the cause of the breakdown is a damaged adapter. After replacing it, there will be no problems with video recording.
Fault: When connected to a cigarette lighter, the screen lights up and after a couple of seconds it immediately goes out. Sometimes a menu may be displayed, but the control buttons do not work.
Solution: Here, device malfunctions occur due to a non-original connection cable. Despite the fact that the wire fits into the microUSB connector, the pinout of the plug is different. The DVR will work correctly only with the cable that comes with the kit. Car charger cords offered by cell phone retailers are not suitable.
Fault: FullHD recorders with a resolution of 1920x1080 may freeze completely after 1-2 hours of operation. You have to pull out the battery or press the Reset button.
Solution: Devices with high expansion have poor compatibility with many cheap memory cards. They need to buy high-speed cards, the class of which is indicated in the technical documentation (they cost an order of magnitude higher).
Fault: Chinese devices periodically turn off, recording stops spontaneously, the navigator changes the route without instructions. Rebooting only helps for a short time.
Solution: The reason lies in a poor-quality charger with a micro-USB connector, namely its thick part, which is inserted into the cigarette lighter. Malfunctions occur due to power surges and short circuits. The problem is solved by buying a new charger.
Fault: After discharging, the recorder does not want to turn on and does not respond to control buttons, including Reset. Found on different models.
Solution: The problem is related to the battery charging mechanism. If the charge is completely lost, the battery cannot accept current, so you need to pull out the battery and apply power directly.
So that you can fix minor problems with the DVR yourself, it is worth taking a closer look at the wiring of the microUSB plug and the process of charging the battery directly.
As already mentioned, non-standard wiring of the plug leads to a malfunction of the device. If it is not possible to get the original wire, just change the wiring on the new collapsible plug with your own hands. The standard layout looks like this:
- VBUS - plus;
- GND - minus;
- ID or NC - total weight;
- D + and D are contacts for signal transmission.
On most Chinese cables, some pins are not used at all, GND is a minus, and NC (or ID) is a plus. Those connectors that are sold in cellular stores do not charge Chinese DVRs, since the NC contact is closed with VBUS. Therefore, you need to purchase a collapsible miniUSB plug, it must have a fourth contact (NC or ID). We change the circuit using a soldering iron, and the DVR will work without failures.
Today, there are universal chargers on sale that can be connected directly to the battery terminals. In the case of DVRs, we only need to give a small starting charge to the battery. We put the contacts of the charger on the terminals and wait a few minutes. After that, you can continue charging in the standard way through a cable with a miniUSB connector.
