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  1. KrisBlueNZ

    DIY Peak Volt circuit alternative

    Yes. A 47 µF capacitor charged to 300V is dangerous. If you connect yourself across it from one hand to another, so current flows through your heart, it can kill you. This is one reason why electricians work with their left hand in their back pocket (assuming their heart is on their left - some...
  2. KrisBlueNZ

    DIY Peak Volt circuit alternative

    Hi there and welcome to Electronics Point :-) I guess when you say "mF" you actually mean microfarads, µF? Because mF means millifarads and a 22 mF capacitor is 22,000 µF! You need to be careful about these things. A 47 µF capacitor will work instead of 22 µF. If you want to keep the same...
  3. KrisBlueNZ

    Yamaha A60 Electronic Organ: No Sound From Lower Keyboard

    OK, we need to wait till then. I'll PM you my email address.
  4. KrisBlueNZ

    Kenwood KR-8050. A+B Speaker selection not working.

    I guess it must be, unless there are some really bad dry joints on the switch pins or broken tracks on the PCB. I would try carefully removing it and opening it up. The problem may be obvious.
  5. KrisBlueNZ

    Help on 74LS165

    That's how it's supposed to work. That's why the serial output is called QH, matching the last parallel input, H. The SPI peripheral in the ARM should be able to handle this; it's one of the four standard SPI modes.
  6. KrisBlueNZ

    Christmas Gift for my 15 year old electronics enthusiast

    Oh, you will be upgrading it! Personally I use lots of resealable transparent plastic bags of various sizes for storing my stuff. They're versatile and cheap, and space-efficient. There's a good argument for keeping really common parts in individual compartments in drawers or kits like that one...
  7. KrisBlueNZ

    Brother MFC-7820N printer/fax/copier- no longer powers up, except LCD backlight

    I was waiting for those voltage measurements and I didn't notice you'd edited post #5. Well, it looks like the power supply is OK. So you need to follow the 5V rail on pin 2 of the connector and see why the rest of the unit isn't doing anything. I found two versions of the service manual...
  8. KrisBlueNZ

    Need assistance with 555 Timer Circuit

    OK. You should link pin 4 to pin 8, and you must add a decoupling capacitor (0.1 µF ceramic) directly between pins 8 and 1. You should also add a decoupling capacitor (same value) between pin 5 and pin 1. Both of these capacitors should connect to pin 1 as closely and directly as possible to the...
  9. KrisBlueNZ

    Yamaha A60 Electronic Organ: No Sound From Lower Keyboard

    Hi there and welcome to Electronics Point :-) There are plenty of people here who can try to help - me, for one :-) The manual and schematics, are they hardcopy or electronic? If they're electronic, I'll PM you my email address to send them to. If they're hardcopy, can you scan them?
  10. KrisBlueNZ

    Switching power supply voltage drops under load

    Right, I Googled Samxon GF series and the first result was the PDF data sheet! You have the 10 mm diameter, 12.5 mm height version. The specifications are 80 mΩ maximum impedance (at 100 kHz) and 865 mA maximum ripple current. It looks like the five large capacitors are not the same - three are...
  11. KrisBlueNZ

    Timer relay, to turn pump on, and then off

    No problem. I'll post something today or tomorrow.
  12. KrisBlueNZ

    Timer relay, to turn pump on, and then off

    It's possible to do it the way you want. When the switch initially activates (flow starts), the pump runs for two minutes then turns OFF. The pump will only be retriggered if flow stops, then starts again. Would that be your preference?
  13. KrisBlueNZ

    Timer relay, to turn pump on, and then off

    Hi there and welcome to Electronics Point :-) I'm afraid I don't quite understand your question. You have a valve in your hot water supply line. As I understand it, valves control the flow. They don't detect flow, and they don't control circuits. Do you mean it's a switch that detects flow? I...
  14. KrisBlueNZ

    Sony Receiver STR - DA555ES Displays "protection fan" when turned on.

    You'll know that devices are dead if the fuse still blows, or the regulator gets hot, or the unit doesn't work (or doesn't work properly). The regulator might have failed because of overvoltage at its input from a power surge, but most likely it just failed internally. Semiconductors do that...
  15. KrisBlueNZ

    Help on 74LS165

    I think you're right to be concerned about the length of the wiring. With a large project like that, with significant currents flowing, just keeping the 0V rails of all the component boards near the same voltage could be an issue! As for the signals, differential signalling is good for noise...
  16. KrisBlueNZ

    Sony Receiver STR - DA555ES Displays "protection fan" when turned on.

    Oh dear :-( Most likely, many of the ICs on the digital board are toast. You can try replacing the 3.3V regulator and reconnecting the wire, but don't hold your breath. http://www.digikey.com/product-detail/en/BA033T/BA033T-ND/658206
  17. KrisBlueNZ

    Need assistance with 555 Timer Circuit

    You won't get very good stability. The problem is leakage current in the electrolytic that's used for timing. When you need a slow oscillator (or any long delay) using a resistor and a capacitor, the resistor and the capacitor both need to be fairly high values. That means the capacitor pretty...
  18. KrisBlueNZ

    Buz103 replacement transistors

    The G D S markings above the pins are a bit of a giveaway!
  19. KrisBlueNZ

    Deal of a lifetime!

    What an amazing score! You lucky guy :-)
  20. KrisBlueNZ

    Buz103 replacement transistors

    No; all four devices are the same. They're all BUZ103 N-channel MOSFETs. The date/factory codes are different, that's all.
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