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Remote control failure solution

2022-08-29 17:14

Fault 1: All buttons on the remote control do not work

Analysis and maintenance: Most of the reasons why all the buttons on the remote control do not work are caused by the damage of the crystal oscillator. If it has been dropped or there is no "beep" sound at all with the radio check, you can directly replace the crystal oscillator with a new one. After replacing the new crystal oscillator, if the fault cannot be eliminated, you should first measure the voltage across the crystal oscillator. When any key is pressed, there will be obvious voltage changes at both ends of the crystal oscillator, which indicates that the oscillator can generate pulse signals. The second is to check whether there is a relatively weak voltage change at the output end of the remote control signal of the integrated block. If there is a change, check whether the driving triode and the infrared emission tube are damaged, otherwise most of the integrated blocks are defective.

Fault 2: Individual buttons do not work

Analysis and maintenance: This phenomenon shows that the remote control is normal as a whole, and the reason why individual buttons do not work is that the circuit contacts of the buttons cannot be effectively turned on. Most of the contacts on the circuit board in the remote control have dirt, which increases the contact resistance or cannot be connected. You can use cotton dipped in anhydrous alcohol to wipe the carbon film contacts, but do not use too much force to prevent the carbon film layer from being worn or peeled off. . Aging or worn out conductive rubber can also cause individual keys to not function. At this time, just stick the tin foil (preferably aluminum foil sticker) from the cigarette box on the conductive rubber contact point. If the above methods cannot restore the remote control to normal operation, check whether the circuit from the input and output terminals of the keying signal corresponding to the integrated block to the contacts has cracks or poor contact, especially the connection between the carbon film contacts and the circuit lines. You can try to replace the integrated block.

Fault 3: The remote control distance is short

Analysis and maintenance: First of all, it should be judged whether the remote control receiving circuit is working normally, and it can be compared with the remote control test machine of the same brand and specification. If the remote control receiver is normal, you should focus on checking two aspects of the remote control: one is whether the 3V voltage of the power supply input terminal of the integrated block is normal, usually the battery voltage is insufficient, which is the most common reason for the reduction of the transmission capability of the remote control; Whether the push triode and infrared emission tube are in good condition can be replaced by test.

Fault 4: Pressing any key only performs a certain function

Analysis and maintenance: It is usually caused by leakage or short circuit between the interdigitated contacts or the leads at the buttons that perform a certain function on the circuit board. Try cleaning the circuit board and conductive adhesive contacts. If the fault cannot be eliminated, check whether the key control input and output terminals of the integrated block perform a certain function for short circuit or leakage.

Before repairing the remote control, you should ask the user what is the fault phenomenon, whether some buttons are not working well or all of them are malfunctioning, whether it is damaged due to mishandling or no reason. It is relatively simple to deal with the failure of individual keys, mostly due to poor contact. You can open the remote control shell, and clean the conductive rubber contacts of the failed keys and the corresponding printed board parts with alcohol cotton balls. If it doesn't work, you can replace the conductive rubber or stick cigarette aluminum foil to the conductive contacts instead. If the problem is that the conductive film of the contact part of the printed board is worn, you can use a bare copper wire of about ∮ 0.4mm to run along the lead, and solder one end of it to the solder joint connected to the conductive film to replace it, and then use 502 fast depending on the situation. The dry glue sticks the thin copper wire on the original conductive film. In the case of accidental breakage, the internal chip of the crystal oscillator is generally shattered, and it is only necessary to replace the crystal oscillator with the same frequency.

In the case of unreasonable damage and all the buttons are out of order, you can first check whether the battery has power, then place a normal radio in the mid-band, place the remote control as close to the radio magnet antenna as possible, and press any button at the same time. Listen to the radio to see if there is a beeping sound (you can also use a multimeter to check whether it has a working current at 5-500mA to determine whether there is a beeping sound). . The infrared emitting tube can be welded and used R×1K block to judge whether its forward and reverse resistance is normal like an ordinary diode. If there is no sound, you must first check whether the power supply circuit of the circuit board is open or the crystal pin is broken, and then replace the crystal oscillator with the same frequency to see if it is normal.

In addition, the remote control will also cause short-circuit failure of the buttons due to water ingress and moisture. At this time, it should be disassembled, and the circuit board and conductive rubber should be cleaned with alcohol.