4000 in 1 Universal A/C Remote KT9018E

Before maintenance of remote control, ask the user what fault phenomenon, whether the individual buttons are not too smart or all failure, whether they are damaged due to failure of hand or damage due to no reason. The handling of some keys is simple and the contact is poor. The remote control shell can be opened, and the conductive rubber contacts of the ineffective keys and the corresponding printing board parts can be cleaned with alcohol cotton balls. If they are still ineffective after drying, the conductive rubber can be replaced or the conductive contact can be replaced by cigarette aluminum foil paper. If the problem is that the conductive film at the contact part of the printing board is worn, it can be replaced by the wire of about 0.4mm bare copper wire along the lead wire, and one end of the wire can be welded to the welding point connected with the conductive film to replace it. Then, the fine copper wire can be pasted on the original conductive film with 502 quick drying adhesive as the case may be. For the case of hand failure, the internal wafers of the crystal are generally broken, only the same frequency crystal vibration can be replaced.

For the condition of no damage and failure of all keys, check whether the battery is powered, then put a normal radio in the medium band, and keep the remote control as close to the antenna of the magnetic rod as possible. Press any key at the same time to hear whether the radio beeps (it can also be determined by measuring whether there is any working current in multimeter 5-500ma), If beep sound indicates that the remote control oscillation is normal, the fault is likely to be in the infrared transmitter or the infrared emitter tube pushing tube. Infrared emission tube can be welded down with R × 1K gear is like a common diode to determine whether its positive and negative resistance is normal. If silent, check whether the circuit board has open circuit and crystal oscillator pin break, then replace the same frequency crystal vibration test to see if it is normal. If it is still abnormal, it may be damaged by remote control IC, and the same type of IC shall be replaced.