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Recent content by pplus

  1. pplus

    ATX Power supply repair

    Look at this.
  2. pplus

    [Moved] Ultrasonic Cleaner Circuit Problem

    I corrected your schematic. I wonder lack of diodes D1 and D5. Any break in the feedback circuit will result in burnout of the diode D2 and the transistors Q3 and Q4. Check feedback and D3, D4, R4, R5, C4, C5. Connect serial your device and 20-40W light bulb. Check oscillation by oscilloscope.
  3. pplus

    SMD part identification

    As a result, this component must be BFR505T. Unsoldered component next to it is the XTAL, not integrated generator, right?
  4. pplus

    SMD part identification

    Look at this. **broken link removed** **broken link removed**
  5. pplus

    SMD part identification

    What is the component unsoldered near?
  6. pplus

    SMD part identification

    I hope you unsolder this transistor before test. Set multimeter in diode/buzzer mode and repeat test.
  7. pplus

    [SOLVED] Problem with an old 10KV/3mA DC high voltage module

    I agree with Brian. BDY55 – BDY56 Turn-on time --0.5μs Turn-off time --2μs Fmax ~ 1/(2*2.5μs)=200KHz
  8. pplus

    [SOLVED] Problem with an old 10KV/3mA DC high voltage module

    Swap new non oscillating BDY56 with oscillating BDY56 to the working unit and check start oscillating. Try find a match pair.
  9. pplus

    [SOLVED] Problem with an old 10KV/3mA DC high voltage module

    Check as pair (2 4) or (2 3). Here's a schematic file LTspice IV to simulate your oscillator.
  10. pplus

    [SOLVED] Problem with an old 10KV/3mA DC high voltage module

    U16.1 = UBEQ12.1+UCR30.1||UBEQ13.1+UCR31.1=(0.6+0.6)||(0.6+0.6) ~ 1.2V. It is right. The absence of oscillations is the result of a low Q oscillation circuit. Check the C26 C27 C28 and and measure inductance of the transformer windings. It seems that the transformer windings are shorted. - - -...
  11. pplus

    [SOLVED] Problem with an old 10KV/3mA DC high voltage module

    We have two facts. Post #12 https://www.edaboard.com/threads/335654/#post1433961 1. Case - no load. Output voltage is 10KV. Supply voltage is 42V. Voltage at emitter of Q7 and emitter of Q6 both are 40V without load. Voltage of point "G" is 42V without load. Measurement is wrong. The voltage...
  12. pplus

    SMD part identification

    I think that is BFR505T NPN. https://www.sos.sk/pdf/SMD_Catalog.pdf 1.0 nH - 470 nH ? **broken link removed**
  13. pplus

    [SOLVED] Problem with an old 10KV/3mA DC high voltage module

    Q9 is closed Open IR33=0.1mA Leak in C13?
  14. pplus

    [SOLVED] Problem with an old 10KV/3mA DC high voltage module

    Check the voltage +95V with load and without it. The matter can be quite simple - a source of DC lost capacity of filter capacitors.
  15. pplus

    [SOLVED] Problem with an old 10KV/3mA DC high voltage module

    Hi agoo! Check the circuit protection. The voltage at the point "U" with the actual load and no load. Base and collector voltage Q13.7 with connected load and no load. With normal load Q13.7 should be closed.
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