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  1. dorke

    Relay operations

    You can make it with all electronic parts, generally a lot cheaper than with a dual coil relay... What are the voltage and current of the fan.
  2. dorke

    Replacing A5sHB transistor (netbook)

    Start with posing a clear photo of the board. and the voltages you measure ,mark where on the board you take the measurements.
  3. dorke

    Gaming headset soundcard repair question

    Looks like the red wire is broken.
  4. dorke

    B & O Penta amplifier repair and Tr equivalents

    With all semis out (as they are now) perform the test from post #18: Tets resistance between output (L1) to GND and ±68V rails. And ±68V rails to GND. note:make sure there is no voltage on the ±68V rails(big caps discharged). Re-check resistors R97-R106(in circuit is fine). With TR27 and TR32...
  5. dorke

    What component is this?

    Like steve suggested, It looks more like a Shielded High Current Inductor. In what part of the circuit is it ,the SMPS ? If so ,you can't replace it with anything but the same part. since you need to know it's current rating and SRF(Self Resonance Frequency)
  6. dorke

    -12Vdc Circuit design

    In general this is bad practice,very bad practice! should be avoided at all cost... there is a thermal runaway danger i.e diode destruction.:eek: Unless the diodes are matched to perfection and are at the same temperature . i.e the diodes are on the same die and same package.
  7. dorke

    CD4511 Decoder Schematic Help!

    Like Harald said, they are pull-down resistors. But you don't need them in all cases, actually mostly you don't;) If you need more help with your clock,do share the schematics... I can guaranty(!) it will be worthwhile:)
  8. dorke

    How to supply 5v at higher current?

    Well you see, You do need to totally specify the requirements of the P.S , otherwise the solution you will get to will be far from optimal in terms of cost/space/efficiency/reliability/performance etc. So Lets start from the beginning,shall we? . 1. What is it "driving"? (as you now say...
  9. dorke

    -12Vdc Circuit design

  10. dorke

    Electronics Project: Dice

    Welcome to EP, Before you get to the PCB. Your project is faulty by design! Connecting LEDs in parallel is wrong. Each LED should have it's own different series resistor or (depending on the LEDs you use and "Power Supply voltage") connect them in series.
  11. dorke

    What component is this?

    Start by measuring it's dimensions. Is it 2020 size? Before you do anything you should totally identify it i.e Power,Accuracy, etc. Have no idea how cooperative Apple tech support is ,you can find out here
  12. dorke

    How to supply 5v at higher current?

    I think it is a bad solution... VOLTAGE TOLERANCE ±8% , i.e. nearly useless in my book:(
  13. dorke

    Amplifier blows power fuse

    Looks like your meter is fine. 4 dead diodes in a bridge suggest there is another short or overload in the circuit. Take them out, and continue checking for more faulty devices down the line.
  14. dorke

    Amplifier blows power fuse

    If the meter is correct then you do have 4 goners... which is very(very!) strange.
  15. dorke

    Chosing the Right Tweeter

    @Hop, 1.The op said the tweeter itself has a writing of 700W (post #10),not the entire box. Since the box may have been build from a collection of speakers of diffrenet brands and put in the box by a "manufacture", it would be hard to get to a conclusions from the cross over values...
  16. dorke

    How to supply 5v at higher current?

    You will probably need a Switch-mode Power supply. There are more details needed. 1.What is the noise level allowed on the 5V. 2.P.S regulation parameters (i.e. how stable is the 5v). 3.How is the heat from the P.S be dissipated Will one of these do? Edit: They are about 30cm height,though...
  17. dorke

    How to supply 5v at higher current?

    What is the input to the P.S ?
  18. dorke

    KO92X. Which electronics SMD part is this?

    A good photo of the device may help. As well as the surrounding devices.
  19. dorke

    DSP/Amp Problem (Reversed Polarity)

    That is great news.:) It is a great feeling to help someone and get something valuable working again. This is what EP is all about, isn't it?;) Rick,congratulations on a work well done!
  20. dorke

    Amplifier blows power fuse

    O.K so we have 5 channels and 10 LM1875 devices. That means each channel is most probably made of 2 bridged LM1875. I would check in ohm test(not diode test!) Pins 3(-VEE),4(output),5(+VCC) to GND for high resistance. and between pin 4 and 3 , and pin 4 and 5 for high resistance. Then check all...
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