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  1. KrisBlueNZ

    LED blinking assembly code

    Hi vead. Please post the listing file for your LED blinking program. This listing will include line numbers, addresses, and the opcode bytes that the assembler has generated for each line. We only need the main section that contains the actual code. It should look something like this. 01 0000...
  2. KrisBlueNZ

    Kenwood Receiver KR-A4070 Issue

    OK. Get back to me when you've tested those inputs.
  3. KrisBlueNZ

    Kenwood Receiver KR-A4070 Issue

    No problem. No, you can forget the idea that using universal remotes with the unit has somehow stopped the front panel buttons from working.
  4. KrisBlueNZ

    Problem with Interrupts - PIC18F1220

    I'm also not too familiar with PICs, but I can answer Harald's suggestions. The PIC has only one interrupt vector (actually, the "high-end" 8-bit devices like this one have two: low-priority and high-priority, if this feature is enabled). The interrupt handler has to go through and test the...
  5. KrisBlueNZ

    Resistor identification

    That's just silly. Every man and his dog has internet access and can learn the resistor colour code. Being able to repair electronic equipment takes a LOT more knowledge than that! Right. Probably also for cost reasons.
  6. KrisBlueNZ

    Kenwood Receiver KR-A4070 Issue

    Right, I very much doubt that using the other remote controls would have any effect. The pushbuttons are scanned one column at a time, multiplexed. This will be a bit difficult to follow without a dual trace scope, but you could try cutting tracks to eliminate the buttons. Actually I suggest...
  7. KrisBlueNZ

    Kenwood Receiver KR-A4070 Issue

    Hi David and welcome to Electronics Point :) So you're saying the front panel pushbuttons don't work but remote control does work? According to the schematic, IC901, the micro on the front panel board, scans the buttons, drives the VF display, and receives the remote control data stream. So it...
  8. KrisBlueNZ

    Wish me luck

    Oh yeah, a Fluke 87 and a handheld scope! I certainly do wish you the best of luck Bob!
  9. KrisBlueNZ

    Python programming course help

    01 curString = s[0] # Set curString to first character of input string s 02 longest = s[0] # Initially, the longest string is the same 03 for i in range(1, len(s)): # Step through s one character at a time, starting from second character 04 if s[i] >=...
  10. KrisBlueNZ

    LED Setup

    If you measure 0V on the PWM inputs to the driver circuit, and on the bases of the 2N3904s, that means the Arduino isn't generating any PWM signals. Disconnect the circuit's inputs from the Arduino's PWM outputs and connect them to +5V, one at a time. Each one will cause the corresponding...
  11. KrisBlueNZ

    Stage Line 500W amp repair project

    Sorry, I'll be clear. Can you measure all of the marked points too.
  12. KrisBlueNZ

    Stage Line 500W amp repair project

    Sorry again. Yes, I agree with Bob, unless there's an intermittent problem and those most recent two sets of readings are with the circuit in different states. The best way to check is to remove Q46 and measure the voltage across R108, positive probe to top end. If there's no voltage (or less...
  13. KrisBlueNZ

    Can someone check this layout to see if its correct plz???

    The 7805, like all normal regulators, NEEDS a DC input. A regulator cannot create voltage where there is none. If you put a rectified but unsmoothed voltage into a regulator, you will get gaps in the output. That doesn't mean the 7805 is crap; it means you're doing it wrong! Yes. A regulator...
  14. KrisBlueNZ

    110VAC On/Off to 5VDC signal

    The simplest option is a relay with an AC coil like this one: http://www.digikey.com/product-detail/en/RT314615/PB961-ND/1095285 You can also make a circuit using an optocoupler. Google isolated mains voltage detector circuit.
  15. KrisBlueNZ

    Audio signal to speakers

    The basic reason is the complex nature of a loudspeaker. I will try to explain, but I'm at the limit of my knowledge here, so some details may be wrong or incomplete. I hope you get the general picture though. Loudspeakers are inductive, because they are constructed from a coil of wire, but...
  16. KrisBlueNZ

    power supply design help

    Good. How many diode drops? Two? Are the diodes in series? Recalculate your peak voltage. Now, the regulator comes next. What regulator are you going to use for your 5V output? Linear or switching? Probably linear, since they're a lot simpler, right? The 78L05 is rated for 100 mA output but...
  17. KrisBlueNZ

    A single pulse on power-on?

    Hi there and welcome to Electronics Point :-) This "line" that has 13~18V on it when the positioner starts up... is this a power supply signal? Can this pulse generator circuit be powered from it?
  18. KrisBlueNZ

    Mosfet selection for switching a solenoid

    Yeah, what Bob said. A TO-220 package doesn't need heatsinking if it's dissipating less than about 0.5W. You can calculate the maximum allowable RDSon from the power and the current: R = P / I2 = 0.5 / 32 = 56 mΩ All of the devices I suggested in post #2 have RDSon < 56 mΩ at VGS = 10V.
  19. KrisBlueNZ

    Finding the Right Caps for a Westinghouse Monitor

    The VZ is the Nichicon series. Googling Nichicon VZ gave the data sheet as the first result. They are described as "wide temperature range". Their ripple current limits are specified, and they're only about a third of the specifications I listed in post #5. Their impedances are not even listed...
  20. KrisBlueNZ

    Can someone check this layout to see if its correct plz???

    If you're getting noise on the 5V from your power supply, either get a better power supply (a regulated, switching type, as used to charge phones) or use a supply with a higher voltage and regulate down to 5V using a 5V linear regulator such as a 7805 or a 78L05, or an LDO (low dropout voltage)...
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