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Recent content by Cirkit

  1. Cirkit

    3.5 digit LCD IC - faulty multimeter (NJU9203)

    Attached is a photo showing the components around the IC. It's a Blue-Point EEDM503.
  2. Cirkit

    3.5 digit LCD IC - faulty multimeter (NJU9203)

    Hello all, I am trying to repair a faulty multimeter which is based around an NJU9203 3.5 digit LCD IC. When the multimeter is powered on, there are no segments displayed on the LCD. How would I check if the IC is faulty or other external components? I have established that the battery is...
  3. Cirkit

    Cable voltage drop - capacitor reservoir

    If you have a scenario where there is a cable (which cannot be shortened) between a battery and a circuit, is it better to have electrolytic capacitors or a super capacitor on the circuit input to help with transient demands from the circuit?
  4. Cirkit

    Weird coil latching problem

    Oops yes, you are right!
  5. Cirkit

    Weird coil latching problem

    Yes quite likely that CR6 and CR7 are the same. Looks to be 1N414x series.
  6. Cirkit

    DAC vs digital potentiometer

    I want the ability to set the same value at power on or be able to adjust it in software. I did think about using a standard analogue potentiometer however, this may drift and requires careful manual adjustment.
  7. Cirkit

    DAC vs digital potentiometer

    What is the advantage of using a DAC over a digital potentiometer? If the digital potentiometer is supplied from a stable regulated supply, is it not serving the same purpose as a DAC? I understand that a DAC may be faster however, for applications where a fixed voltage is set at power on...
  8. Cirkit

    Microwave Inverter PCB (F6645BA01GP) - Shorted Bridge Rectifier

    I removed the bridge rectifier and IGBT from the PCB and tested again. The IGBT is also shorted out! What is likely to have caused this?
  9. Cirkit

    Microwave Inverter PCB (F6645BA01GP) - Shorted Bridge Rectifier

    Hello all, I am attempting to repair a F6645BA01GP microwave inverter PCB (photos attached). The shorted bridge rectifier tripped the circuit breaker. Before anyone mentions it, I did check that all the high voltage capacitors were discharged before testing the components on the PCB. The IGBT...
  10. Cirkit

    GFG TVS Diode

    Is anyone able to identify this TVS diode marked GFG? I don't recognise the manufacturer's logo? It's from a switching regulator circuit.
  11. Cirkit

    Wireless doorbell chime - no sound

    I am trying to troubleshoot a wireless doorbell chime. It started to fail with a short chime and then no chime, just a flashing LED. The two ICs I cannot identify are: F0R1958 FLC-3A-58 Both are SOIC-8 packages.
  12. Cirkit

    Faulty LED driver (BREL-2D-36T)

    What would cause the diode to fail in this way? Does an ultrafast diode have to be used? Do you think I should also replace the capacitor?
  13. Cirkit

    Faulty LED driver (BREL-2D-36T)

    Yes both measured out of circuit.
  14. Cirkit

    Faulty LED driver (BREL-2D-36T)

    I am trying to repair this constant current LED driver. The output diode (MUR460) is reading a forward voltage of 0.071V and a reverse voltage of 0.087V. The forward resistance is 197Ω and the reverse is 218Ω. So clearly faulty. I have also measured the 330μF output smoothing capacitor and it...
  15. Cirkit

    PIR LED 12V light circuit recommendations wanted.

    The specifications for the HC-SR501 seem to suggest it will operate from 12V. So you can connect the TTL output via a 1k resistor to the base of your transistor and drive a fair few of your LEDs in parallel.
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