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  1. KrisBlueNZ

    "DC 3.7v to 9v 1A" Need Help..

    Do you see a problem here?
  2. KrisBlueNZ

    "DC 3.7v to 9v 1A" Need Help..

    What voltage are you getting out of the DC-DC converter? Have you tried adjusting the output voltage? Post a link to the DC-DC converter you're using. "DC-DC Adjustable Step-up Power Converter Module XL6009" is not enough detail. There are many DC-DC converters that use the XL6009. Post a...
  3. KrisBlueNZ

    No vertical in crt tv(Need Help)

    Yes; they look to be the same!
  4. KrisBlueNZ

    power supply design help

    Since this is just homework, if you don't have the actual specifications, you could make up some numbers to use in your calculations. This would prove that you understand the important factors and quantities that should be taken into account when designing a power supply, and how to use them in...
  5. KrisBlueNZ

    No vertical in crt tv(Need Help)

    I'm not saying it's normal; I'm saying that you can't tell for sure. If you're sure that the 28V rail at IC501 is not present, I think replacing those parts will probably fix the problem. D806 could also be faulty and would be worth replacing "on suspicion" as well. Good luck!
  6. KrisBlueNZ

    Stage Line 500W amp repair project

    It's hard to say how close we are. There might be just one problem to fix, then everything will go smoothly, or we might have to spend a while fault-finding. There is a second set of output transistors that are not fitted, that would improve the reliability and drive capability of the amp. You...
  7. KrisBlueNZ

    power supply faulty

    Can you take a clear photo of each side? See https://www.electronicspoint.com/resources/how-to-take-photos-of-circuit-boards.6/ and https://www.electronicspoint.com/resources/photos-with-phones.27/
  8. KrisBlueNZ

    Information on tft screens

    I'm sure you're smart and would be able to learn it all eventually, but there really would be a huge amount to learn. Start by looking at Dave Jones's basic description of FPGAs: ... and Dave is a very smart and experienced design engineer. You would need one of those and a 512 KB SRAM to...
  9. KrisBlueNZ

    Rascal alarm

    Are you talking about passive infra-red motion detectors? That control light bulbs? And the lights won't turn off? Try powering the thing off for five minutes then trying again. Otherwise, post some basic information - manufacturer and model of the PIR would be a start. And upload a photo of...
  10. KrisBlueNZ

    Information on tft screens

    I'm afraid driving a TFT display panel is not easy. The display needs to be constantly refreshed with pixel data at a fairly high rate. This can't be done by the CPU; extra hardware is needed to hold the image (480 × 272 × 3 = 382.5 kilobytes) and generate the continuous RGB data stream for the...
  11. KrisBlueNZ

    Projects involving vintage CPUs

    I'm not sure how to handle this. I don't want to delete your post, since others have posted in response to it. I'll ask Ian what to do.
  12. KrisBlueNZ

    MOSFET H-bridge, weird effect...

    Right. That's why we recommend them! And speaking of recommendations, check out the pricing and specifications on this one: http://www.digikey.com/product-detail/en/NTD4906N-35G/NTD4906N-35GOS-ND/2194521
  13. KrisBlueNZ

    Projects involving vintage CPUs

    chopnhack wouldn't say a nasty thing about his worst enemy. Well, maybe he would. But not about you, I'm sure.
  14. KrisBlueNZ

    Microphone circuit assistance?

    You mean the third kit? Yes. You'll need to add a resistor, and mount the socket somehow. That sounds like a good idea. Cool! No thanks! But feel free to ask all your technical questions here on Electronics Point. Perhaps you should introduce yourself in the general chat forum and tell us...
  15. KrisBlueNZ

    power supply faulty

    You would normally expect the measured capacitance to be close to the printed value, but with components from certain countries, you can't necessarily believe the numbers. If both of them measure 750 µF the power supply will still work. And mains filter capacitors don't fail very often. It's...
  16. KrisBlueNZ

    Microphone circuit assistance?

    Yes, they get their power from the board. Any amplifier board that has a built-in electret mic, or is designed to work with an external electret mic, should work with your headset. Ideally you should separate the supply circuit (just a resistor coming from the positive supply) from the signal...
  17. KrisBlueNZ

    power supply faulty

    Yeah, I think the 1600 µF marking is a lie. At that size, even 750 µF is a lot. Why do you think they're "fried"?
  18. KrisBlueNZ

    Help on 74LS165

    I don't understand why that would make it "not possible". Of course. You would need a separate board for the main controller no matter which method youse. It would communicate with the other boards using RS-485 (my suggestion) or multiple SPI channels. Yes sure, but making something that works...
  19. KrisBlueNZ

    power supply design help

    I estimated it, and I listed the factors that you need to know in order to calculate it accurately. Once you answer those questions for yourself, you can calculate a more accurate number to use in the following calculations. I asked you two questions, at the end of the last two paragraphs. They...
  20. KrisBlueNZ

    MOSFET H-bridge, weird effect...

    OK, so the transistor's base-collector junction will conduct and this will pull the base negative, causing zener breakdown in the base-emitter junction. So if the catch diodes were present, as we agree they should be, a BJT bridge driver and a MOSFET driver would both brake the motor. I see...
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