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  1. KrisBlueNZ

    stereo capacitors

    OK, that sounds like the fuse is OK. You can try measuring again on the 2k range. You should get a low number - something greater than 0.00. If that's OK we need to check the voltages coming out of the transformer. Find C92 and C96 - they are the big electrolytic capacitors near where the cable...
  2. KrisBlueNZ

    Hello, I am khofo

    Cool! Well, ask us anything. We have people here with all kinds of experience.
  3. KrisBlueNZ

    Nixie Clock

    Is it IC4 you're replacing? That one shouldn't even get warm. You could use an IC socket for it. BTW when you're removing the old one, cut off the leads one by one with a side cutter, flush with the sides of the IC. It's a lot easier to remove the leads individually than to try to remove the...
  4. KrisBlueNZ

    12V - 350V 200mA converter for motorcycle CDI

    So you have an automotive input voltage (around 12V)? Are you sure 200 mA is enough? What's the capacitance you're charging, and what's the maximum spark per second rate? You would need a boost/flyback controller IC driving an external MOSFET. The converter might need to be optimised to handle...
  5. KrisBlueNZ

    Resistors in Parallel

    You tried it without "^2"? Just addition, subtraction, multiplication and division symbols?
  6. KrisBlueNZ

    Resistors in Parallel

    Yeah, I imagine it doesn't like the square brackets. Just use parentheses for all nesting levels.
  7. KrisBlueNZ

    Stereo output 3 or 4 wires

    Headphone amplifiers are designed to drive headphones. Headphones have three-contact connectors. The impedance of your headphones, around 30Ω, is typical for headphones. Therefore a headphone amplifier will be suitable. The board you bought is NOT a headphone amplifier, nor was it advertised as...
  8. KrisBlueNZ

    LED bulb effectiveness

    How did you determine that your circuit draws 9W?
  9. KrisBlueNZ

    Voltage Regulator IC

    The LP4951 is no longer manufactured in through-hole - at least, not by Texas Instruments, which absorbed National Semiconductor, the original manufacturer. You can get adapters to convert the new IC to fit the old PCB position. These are called SOIC to DIP adapters and there are lots of...
  10. KrisBlueNZ

    Capacitor Value

    Hi Andy and welcome to Electronics Point :) 4.7 μF, 400V, ±10% (the 'K' means 10%). http://www.digikey.com/product-detail/en/ECW-FD2W475J/P16728-ND/4271850 Edit: The ones you have there look like "MKT" types made by Philips (now BC Components, part of Vishay). The data sheet for the same or...
  11. KrisBlueNZ

    Hello, I am khofo

    Hi Khofo and welcome to Electronics Point :-) What kinds of things have you hacked?
  12. KrisBlueNZ

    Boost converter 12V to 36V (25 mA load) using 555

    As I said in post #81, that circuit is not a good starting point for a high-energy, high-voltage converter. Yes, you should start a new thread. In the thread title, mention boost converter for CDI.
  13. KrisBlueNZ

    Timing Circuit? Counter?

    Yeah :-)
  14. KrisBlueNZ

    Timing Circuit? Counter?

    Yes, engineering is like that. Lots of things to check to make sure it will work reliably. Thanks but no payment is necessary. VIN is the voltage to be monitored. The top wire is positive and the bottom wire is negative. I assumed that the negative side of the voltage you're monitoring is...
  15. KrisBlueNZ

    Harman/Kardon HK6500. Loudness not working when button is pressed

    I don't know what sort of reputation NTE has generally, but they have a bad reputation with me. Reputable companies like ON Semiconductor, Texas Instruments, Fairchild, NXP, etc provide complete and detailed information on their products, including minimum/typical/maximum values wherever...
  16. KrisBlueNZ

    Harman/Kardon HK6500. Loudness not working when button is pressed

    Yes you are better to leave the originals in. Perhaps you have a friend who has a credit card?
  17. KrisBlueNZ

    Stereo output 3 or 4 wires

    That amplifier is rated for 3+3 watts into two 4Ω speakers. It uses the Diodes Inc PAM8403 (http://www.diodes.com/datasheets/PAM8403.pdf). The speakers must be wired separately because each amplifier has a bridge-tied load ("BTL") output configuration. See...
  18. KrisBlueNZ

    Harman/Kardon HK6500. Loudness not working when button is pressed

    If they'll fit, yes, but you would be better to buy the right thing from Digi-Key when you order the replacements for Q421~428. Don't tell me you're going to use NTE "equivalents" for them as well. I've looked at the parts that NTE claim are equivalents for the transistors in your amplifier, and...
  19. KrisBlueNZ

    automatic switch

    Hi Ryan and welcome to Electronics Point. The following may be suitable replacements. Download the data sheets and check the relevant parameters to make sure. BF469,471 (NPN): http://www.digikey.com/product-detail/en/KSC3503DSTU/KSC3503DSTUFS-ND/1049721 BF470,472 (PNP)...
  20. KrisBlueNZ

    Nixie Clock

    Knock yourself out :-)
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