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  1. KrisBlueNZ

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

    Thanks... I sure hope the design lives up to my expectations! But an oscilloscope is only second to a multimeter in its usefulness and versatility, and I hope you will quickly justify your investment!
  2. KrisBlueNZ

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

    That's great! I'm looking forward to seeing some scope traces - the waveform across RS, and the drain-source waveform for Q1 would be good places to start. I can't suggest anything to try until you have the scope.
  3. KrisBlueNZ

    How Transistors Work

    That's an interesting site and I would be interested to hear opinions from Adam and Steve, both of whom have mentioned that it's more accurate to consider a transistor a voltage-controlled device than a current-controlled device. But to be able to make practical use of transistors, the...
  4. KrisBlueNZ

    Dancing Baby Groot

    The thing in the video looks like it's driven by a motor with a gearbox to slow it down, mounted vertically, driving a piece of stiff wire that has been bent into a staggered shape like the picture below, with the figure built around it. I guess it would need some kind of low-friction sheath...
  5. KrisBlueNZ

    Yamaha PSR530 Keyboard, No Display

    OK, photos are probably not that important. But you're pretty limited with just a multimeter. Here's a good place to start: the power supply. Voltage comes in on CN701 at the right and is "regurated" by four devices. I have marked their output pins A, B, C and D in the diagram above. Here...
  6. KrisBlueNZ

    Yamaha PSR530 Keyboard, No Display

    That unit has a completely separate power supply. Problems with capacitors in the synth are very unlikely. Did you give the main board a very careful thorough inspection? What service equipment do you have? Multimeter? Oscilloscope? Logic probe?
  7. KrisBlueNZ

    Yamaha PSR530 Keyboard, No Display

    Why do you suspect capacitors? Synths are pretty low-power devices and usually have a small mains transformer, not a switching power supply. Switching supplies are used when higher power is needed and noise is not a problem. No one is going to be able to say "it's this component here", unless...
  8. KrisBlueNZ

    Yamaha PSR530 Keyboard, No Display

    If the keyboard has a separate circuit board, and there's no way for liquid to get to the main circuit board, it's not very likely. I'm not familiar with that model. Synths that I've seen do have a separate circuit board for the keyboard but it doesn't completely protect the main board below it...
  9. KrisBlueNZ

    Yamaha PSR530 Keyboard, No Display

    Yes, but the circuit board under the keyboard assembly doesn't just do the keyboard functions. Usually there's just one main board that does a lot more than just the keyboard interfacing.
  10. KrisBlueNZ

    Op Amp

    It's one of those "100-in-1 experiments"-type kits for learning electronics by tinkering.
  11. KrisBlueNZ

    Yamaha PSR530 Keyboard, No Display

    Hi there and welcome to Electronics Point :-) Synth problems that progressively worsen may be due to liquid getting between the keys and dripping on the circuit board below. The liquid may be sweat from your furrowed brow as you rock out, or drool if you let the drummer use it, or some other...
  12. KrisBlueNZ

    Op Amp

    That circuit is just an experiment to demonstrate how a single-supply non-inverting amplifier with a gain of 10 (Edit: ... gain of 11...) and a reference voltage of 0V will behave as the non-inverting input voltage is adjusted from 0V to VCC. There is no need to worry about biasing. It is not...
  13. KrisBlueNZ

    Chicken Coop Door Opener

    What kind of errors? It compiled OK for me. Yes, OK. I'll go through the code and explain how it works. symbol button_state = C.3 ; Input pin with manual pushbutton (low while pressed) symbol light_dark_led = C.0 ; Output pin with light/dark indicator LED (high illuminates) symbol...
  14. KrisBlueNZ

    Measuring Sine Wave Using ADC

    Oh, come on! Do you have a calculator? What is the period of one cycle of a 2 kHz sine wave? (Hint: the period, in seconds, is 1 / freqency, in Hz.) How many 5.5 µs periods will fit into the cycle period? (Another hint: use the division button on your calculator.) See if you can work it out for...
  15. KrisBlueNZ

    Mini hi-fi Sony FH-B411 cd player won't play music, but tray works perfectly

    http://www.google.com/search?q=clean+laser+lens+cd+player
  16. KrisBlueNZ

    Need help with relay calculation

    If it's a 5A relay, that rating is for each pole. So a three-pole 5A relay can switch up to 15A. But I don't think you can connect two or three poles in parallel and switch more than 5A with them, because the poles won't close and open at exactly the same time. You could switch three separate...
  17. KrisBlueNZ

    Measuring Sine Wave Using ADC

    Yes. See post #11.
  18. KrisBlueNZ

    Measuring Sine Wave Using ADC

    It's needed to centre the input voltage half way between the minimum and maximum voltages that the ADC can convert. This is required for every ADC that I've ever used. Perhaps there are some that convert both positive and negative voltages, and use 0V as the centre value, but the MAX1204 isn't...
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