General reasons and solutions of digital TV remote controller lights flashing all the time;
1. The remote control circuit board is short-circuited and the indicator light flashes. Generally, you can take out the battery, disassemble the remote control, wipe the circuit board with alcohol, and then put it back into normal use.
2. Due to the leakage of components or lines on the remote controller, the indicator light flashes. Generally, you can remove the battery, turn on the remote control, replace components and related circuits, and return to normal.
3. If the indicator light flashes, but the function of the remote controller is normal, it is recommended to ignore it and continue to use it. If the function is abnormal and the buttons are invalid, it is recommended to replace the remote controller directly. You can contact the set-top box to replace the original remote control after sale, or you can buy an external remote control. If you want to solve this problem conveniently, it is a good choice to buy a new one.
Determine the fault location of the remote receiver:
Once it is determined that the far-end receiving circuit is not working properly, the following methods can be used to distinguish which part of the circuit the fault comes from, whether it is the high amplifier circuit, the super-upgrade circuit or the amplification and shaping circuit.
(1) When checking the amplification and shaping circuit, the input/output point of the signal is the key to find the fault. The specific method is to transmit the signal with a remote controller and observe whether it is amplified with an oscilloscope. The shaping circuit has signal input (such as LM385F⑤ pin), such as signal waveform, which shows that the high amplifier circuit and the super-booster circuit are basically normal. When the amplifier fails, the shaping circuit;
If the signal cannot be measured, the fault occurs before the super-lifting circuit: by detecting the amplification and shaping circuit, the voltage at the LM358 pin can be measured and compared with the normal value. If there is an abnormality, it is mainly to damage the integrated circuit itself.
(2) When repairing the surge circuit, first check the DC voltage of the transistor. If it is abnormal, check the DC bias circuit or the transistor itself. After the DC bias voltage is normal, check the AC feedback circuit, and it is best to check the patch capacitance by replacing it.
(3) For the maintenance of the high-frequency amplifier circuit, the method of checking the DC working point of the high-amplifier tube first and then checking the coupling element is also adopted. Generally speaking, it is not difficult to find the faulty parts.
Because of the low voltage and low current, the remote control receiver generally does not burn out the circuit board, and the damage rate of transistors and integrated circuits is not great. The highest failure rate is the deviation of receiving frequency, which is mainly due to the damping of water or circuit board to prevent the oscillation of hypercycle circuit. Do more cleaning and flooding, measure more voltage (waveform), and remove components as little as possible.
The receivers used in automobile anti-theft system, whether they are sensors or capacitors, whether they are discrete in-line or patch devices, or hybrid (patch devices are resistors and capacitors, and in-line devices are transistors, integrated circuits and electrolytic capacitors), are almost completely interchangeable. Just find the corresponding relationship between grounding (grounding) +V (positive power) and (signal output) and adjust the receiving frequency of the receiver. Only the reception frequency.