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External LED Lamp Problem: Blinks, Flashes - Diode, Capacitors, Transistors Inspected

sebaele22 35103 16
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  • #1 16856784
    sebaele22
    Level 30  
    Hello, the problem with the lamp. When connected to the network, the flashing lamp flashes. Looking through the electronics I did not come across anything, capacitors un-boiled, diode transistors working.
    Could it be the fault of the diode itself? I'm sending pictures.

    External LED Lamp Problem: Blinks, Flashes - Diode, Capacitors, Transistors Inspected

    External LED Lamp Problem: Blinks, Flashes - Diode, Capacitors, Transistors Inspected

    External LED Lamp Problem: Blinks, Flashes - Diode, Capacitors, Transistors Inspected

    greetings
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  • #2 16857031
    madamsz1
    Level 41  
    You can always check how you have something to hook it to, but usually this behavior can be from the converter that gives you the output, and after a while limits. Did you measure the led voltage?
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  • #3 16857041
    zdzichra
    Level 32  
    This is probably the fault of the inverter. The Chinese will sell and act for a short time. The electrolytic capacitors are not bulged, they do not have capacitance, the same applies to other capacitors. The transistors and diodes on the meter may seem functional but only a substitute for another will give you real response. I have many LED lamps that fell in a similar way. I have cut down the converters, adapted to 12 or 24V voltage and serve as basement lighting or car work.
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  • #4 16857118
    sebaele22
    Level 30  
    Well, I do not have anything to connect the same LEDs :-( .
    As for the voltage, I measured them after disconnecting the diode and the voltage was within 60V step.
  • #5 16857171
    zdzichra
    Level 32  
    It was necessary to measure with the diode also to jump only in smaller amplitude. The driver is dead. If you buy a new inverter or you can convert it to eg 12V and you will have to work on the car or to use eg on the plot.
  • #6 16857502
    sebaele22
    Level 30  
    With the diode also the voltage jumps, but by a larger amount of V.
    I would like to fix it without changing anything, only where to start?
  • #7 16857542
    zdzichra
    Level 32  
    From the purchase of a new inverter. If you want to play with yourself, first measure the voltage behind the bridge or over 300V, check the capacity of the capacitors, check the resistors, replace diode transistors. It is uncertain that the transformer has no inter-turn short-circuit and here is winter cruel unless that you will scroll.
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  • #8 16857716
    sebaele22
    Level 30  
    Hmmm I do not know what to do anymore :-(
  • #9 16857741
    zdzichra
    Level 32  
    Check the voltage and capacity at least the more easily available because the surface element require a lot of patience and accuracy. Check what you can check reliably and 100% later only the thought of surrendering :D
  • #10 16871149
    lemu
    Level 19  
    With what frequency the diode is flashing - 25 Hz, or slower?
  • #11 16871577
    sebaele22
    Level 30  
    Every 2 seconds something like that :-)
  • #12 18320418
    paul0
    Level 15  
    Such flashing can also be caused by damage to the diode itself or the connections.
    The diode and the parts of the housing heat up, stresses cause a break in the circuit in the damaged place, e.g. crack, defective solder, it cools down, the circuit closes again and the cycle repeats itself.

    I have encountered this type of damage many times, even in brand LED luminaires.
    Often the cause is a design flaw - the cooling capacity is too low. Sometimes you can see damage - if it is a luminaire with many diodes connected in series (the power supply is a current source, with a certain voltage range on the load, which is known by the fact that the power supply has the current and voltage range on the load), you can see that one diode is damaged - it has a different color or there is a different color at some point. If the power supply has a large voltage range on the load, you can reduce the power of the luminaire by removing and bridging some of the diodes, which will reduce the amount of light but also the thermal power, which will lower the temperature and extend the life of the luminaire.

    There are a series of luminaires with different powers, which have the same power supply, Philips 50W and 70W led luminaires (I do not remember the type, they are from the same series) have the same power supply, and they differ in the number of diodes in series, modules with diodes in the whole series are the same, there are more modules connected in series in the luminaires of higher power. In these luminaires there was a problem with the bridges between the modules - they were of some very difficult solder alloy, so that even in the factory they had a problem soldering it, when I replaced all the bridges for copper.
  • #13 18320455
    750kV
    Level 33  
    After all, the author of the topic wrote:
    sebaele22 wrote:

    As for tension, I measured them after disconnecting the diode and the voltage was in the 60V range.

    So what do these effects have to damage the diode structure, stress, or connections in the LED module itself ..?

    Try to change the electrolytic capacitors at the inverter output (photo 2 right side). When the voltage increases, one of them can overload the system (short circuit, leakage), which the current limiter "sees" as the rated diode current.
  • #14 18320508
    teskot
    Level 37  
    90% is the fault of the electrolytic capacitor with the R6 resistor visible in the first picture.
  • #15 18320697
    sebaele22
    Level 30  
    I will exchange it out of curiosity if I find one :-)
  • #16 18320912
    teskot
    Level 37  
    It may be different, with a capacity equal to or greater, and the same voltage of 25V or more.
  • #17 18321783
    paul0
    Level 15  
    If it is a power supply, measurements should be made with the power supply loaded, so that the voltage on the load is within the range specified on the power supply plate. The power supply without load, as well as with a short circuit at the output will behave unusually, different power supplies react differently to such a state.
    These power supplies that I dealt with in the event of a short circuit would turn off, and when the voltage on the load was too high, some of them would turn off, and some would have the effect of pulsing - the power supply was supplying current, detecting too high voltage on the load, ceasing to supply current after a certain time ( this time was different for different types of power supplies, range 1 ... 5s) the cycle was repeated.

    To check if the PSU is to blame or the diode, it was necessary to load the power supply with a resistor, so that the voltage across the resistor was within the voltage range on the load given on the plate of the given power supply. If the voltage on the load connected in this way was stable - the reason was the diode circuit. If not - the reason was the power supply, which was then replaced with a new one (in these fittings the power supply was unreparable - electronics flooded with chemically hardened resin)

Topic summary

The discussion revolves around a malfunctioning external LED lamp that exhibits flashing behavior when connected to a power source. The user has inspected various components, including capacitors, diodes, and transistors, without finding visible damage. Responses suggest that the issue may stem from the inverter or the electrolytic capacitors, which could be failing despite appearing intact. Recommendations include measuring voltages across components, replacing suspected faulty capacitors, and considering the inverter's output characteristics. The importance of testing under load conditions is emphasized to accurately diagnose the problem. Additionally, potential design flaws in the LED module are noted as contributing factors to the malfunction.
Summary generated by the language model.
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