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  1. KrisBlueNZ

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

    OK, I've marked the positive and negative rails in red and blue respectively. To find the positive rail on the board, look for any of the componetns that are connected to it on the schematic - R929, R937, R941, R930, R938 and R942 - and look under the board for a track that connects them...
  2. KrisBlueNZ

    ATX PSU 24v mod

    Do you want to change the output voltage to 24V? If it's a switching power supply, that's probably pretty easy to do. Upload photos of both sides, and close-ups of both sides of the output section. Make sure we can see the components and tracks clearly. See...
  3. KrisBlueNZ

    machine language to assembly language

    I know what an assembler does. I did a Google search for 8051 opcode map and found the following pages that might help you: http://www.keil.com/support/man/docs/is51/is51_opcodes.htm http://turbo51.com/documentation/8051-opcodes http://www.carousel-design.com/OpCode_Chart.html The last one...
  4. KrisBlueNZ

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

    I guess the problem will be in the loudness circuit. Here's the schematic of it: The left and right audio signals enter on the left and are switched by SW6. In the position shown, the signals go straight through; in the other position, the loudness circuit is switched in. The first thing to...
  5. KrisBlueNZ

    Problem with Vintage Pioneer receiver SX-1000TW Output

    The first diagram shows the current into the collector of Q1 as 20 mA. Almost all of the DC current in Q1 flows straight down, through the two output transistors. It will cause a voltage drop across the emitter resistors according to Ohm's Law: V = I × R where I is the current, 0.02 amps, and R...
  6. KrisBlueNZ

    12V - 36V 30mA Converter using LT1173

    Bzzzzzt! LOL wrong. Even if "80%" was a meaningful way to quantify how well the circuit works, it would be wrong. Good. You don't need a PCB; prototyping board is enough.
  7. KrisBlueNZ

    Problem with Vintage Pioneer receiver SX-1000TW Output

    No voltage at all across R29? Nor across R30? That means there's no DC current flowing in the output stages. You may be able to get some current flowing by adjusting VR5 and VR6. Adjust VR5 for 0.014V across R29 and adjust VR6 for 0.014V across R30.
  8. KrisBlueNZ

    ATX PSU 24v mod

    Yes it is possible. I described this in post #2 on this thread.
  9. KrisBlueNZ

    Problem with Vintage Pioneer receiver SX-1000TW Output

    Re Q801/802, yes there is a significant difference between left and right channels. But I think you have the collector and emitter voltage markings exchanged on the left channel. The 13.6V measurement will be the collector voltage. The voltages you've marked on the right channel might be right...
  10. KrisBlueNZ

    Problem with Vintage Pioneer receiver SX-1000TW Output

    Hi there and welcome to Electronics Point :-) I would be suspecting C8 for loss of capacitance causing loss of bass, but possibly also C802, C804, C810, C814, C818. If you replace them, you might as well replace the ones in the left channel as well - when one component fails, other similar...
  11. KrisBlueNZ

    machine language to assembly language

    Normally you use a program called a disassembler. This may be a program that runs on a computer that processes a binary or hex file, or it may be a program that runs on the target system and disassembles memory directly. You can do it manually as well, if you have an opcode map. The data sheet...
  12. KrisBlueNZ

    ATX PSU 24v mod

    I haven't done it but I can tell you what you need to do. You need to re-wind the 12V secondary of the transformer with twice the number of turns. You can remove the 5V and 3.3V secondaries, so you'll have plenty of room on the bobbin. You may need to change the rectifier diode(s) on that rail...
  13. KrisBlueNZ

    12V - 36V 30mA Converter using LT1173

    OK, the reason for the low switching frequency is that this converter is a gated oscillator type. It doesn't switch while the output voltage is above the target voltage. You need to put a significant load on it before you will see the actual oscillator frequency at the SW1 pin. If you've built...
  14. KrisBlueNZ

    List of EDA packages

    Thanks Olivier for those additions. There were two I didn't add: http://www.cadcam-group.eu/electronics/software/p-cad/ (PCAD) seems to have been taken over by Altium; that site mentions "P-CAD 2006". http://www.rimu.pl/hs/rimuuk.html (RIMU) seems to be very old. The list of supported...
  15. KrisBlueNZ

    List of EDA packages

    These packages include schematic "capture" and PCB layout. Some include autorouters. The commercial packages also include autorouters, simulation, and other features. Web-based (run in browser): 123D Circuitshttp://www.123dapp.com/circuits - Upverterhttp://www.upverter.com Free for publically...
  16. KrisBlueNZ

    List of EDA packages

    KrisBlueNZ submitted a new resource: List of EDA packages - Lists of EDA (schematic and PCB) packages: free/open-source, free limited versions, and commercial Read more about this resource...
  17. KrisBlueNZ

    can interfacing with arm

    I guess that means they don't have them built in.
  18. KrisBlueNZ

    12V - 36V 30mA Converter using LT1173

    Ah, OK. But re Steve's comment in post #4, what is the switching frequency? The data sheet says it's fixed at about 23 kHz. But there's ripple at a much lower frequency on the output. Show us a photo of your construction. Did you build it up on a breadboard? (Hint: the right answer is NO...
  19. KrisBlueNZ

    Power source help

    LOL Adam :-) That all matches reality except for the part about me using up that energy. Usually I would just eat ten burgers then go to sleep :-) Your analogy does explain how energy is lost pushing current through a resistance, but I'm still not clear on how the potential difference...
  20. KrisBlueNZ

    Chicken Coop Door Opener

    Yes, that code looks right. But it's just as important to update the comments! Suggestions: Change comment on line 22, "symbol limit_switch ..." to say that the input is low when the door is at its open limit. (Edit: that should say "... at its closed limit".) Add a note to the comment block...
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