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  1. KrisBlueNZ

    12v LED Strobe Controller

    I think your best option would be http://www.gmelectronic.com/vcr20d220kar-p119-374
  2. KrisBlueNZ

    Bush DAB Radio

    I can't find any service information for that model number. I suspect it will be difficult to locate the problem and to get replacement parts. I think you would be better to throw it away and buy a good quality radio. If you want to keep going, try following the track on the underside from the...
  3. KrisBlueNZ

    Help with Gain

    I agree that using dB for a pure voltage ratio, with no associated impedance, takes the idea somewhat out of context, but it's normal. The dBV unit is widely used in audio and has no associated impedance; it's simply a convenient way to represent an absolute AC voltage level because...
  4. KrisBlueNZ

    Sony Model #KV-25XBR - an oldie but goodie

    That site charges for manuals. Did you buy one? If so, can you upload it somewhere so I can get it?
  5. KrisBlueNZ

    using two momentary switches with DPDT Relay for f/r dc motor control

    I've never tried it. The problem with DC loads is the inductive kick-back from the load (the motor) which causes arcing, especially if the contacts move slowly or don't separate very far. I think this would worsen by a factor of four for every doubling of the voltage. You should have a 1N540x...
  6. KrisBlueNZ

    Sony Model #KV-25XBR - an oldie but goodie

    Hi there and welcome to Electronics Point :-) I haven't been able to find technical information on that set. I tried my usual go-to site for service information, elektrotanya.com, and I tried a Google search. If you can find a service manual, or even just a schematic, post a link to it here...
  7. KrisBlueNZ

    transformers back to back - why won't work?

    So Adam was right in post #18 that losses and corresponding heat dissipation are the limiting factor? I think I was thrown by his comment that excessive primary current would cause the core to saturate. That's not true, is it? Yes, exactly. That's why I asked the question! Yes, two things are...
  8. KrisBlueNZ

    Bush DAB Radio

    Yes Dave, it could be either way round. It is named CTRL, either with or without an overbar. It is not mentioned in the text of the data sheet. So it's impossible to say which way round it is supposed to work. It was at 3.2V, which should be considered high, and grounding it had no effect, so I...
  9. KrisBlueNZ

    PIC emulator software

    No problem.
  10. KrisBlueNZ

    Translate stripboard layout to schematic diagram

    OK, that's a good idea. But you need to name the horizontal positions as well because there are many track cuts. The 0V rail is on track 3 from A~ P. It is also linked at G to track 7 from A~G, and at P to track 2 from N~U. There are two positive supply rails and I can't tell for sure how...
  11. KrisBlueNZ

    Help with Gain

    dBV is dB relative to a reference level of 1V RMS. It's used when you're specifying an absolute signal level. When you're specifying a gain or attenuation, i.e. the ratio between two voltages, you just use dB.
  12. KrisBlueNZ

    Interrupts: privileged vs. non-privileged modes

    I'm not familiar with that architecture. I suggest you do what I would do: get all the documentation together, and search through it for occurrences of "privileged". That will give you a quick overview of the behaviours that are affected by whether the core is running in privileged mode or not.
  13. KrisBlueNZ

    Audio Generator

    Sounds good! Fair comment. An audio signal transformer would eliminate most of the noise, and provide some protection from damage, but they can be expensive, especially if you need a very flat response. The machines you had this problem with, what brands were they? And did they have genuine...
  14. KrisBlueNZ

    Interrupts: privileged vs. non-privileged modes

    Which architecture?
  15. KrisBlueNZ

    Help with Gain

    The bel, and the decibel, are measures of ratios, not necessarily power ratios. dB can be used to express current ratios and voltage ratios; the formula is dB = 20 log10 (VOUT / VIN).
  16. KrisBlueNZ

    PIC emulator software

    We can change the thread title Chris. Just let me know what you want to call it.
  17. KrisBlueNZ

    Bush DAB Radio

    OK, the amplifiers are type NS4148, made by "Nsiway". I found a data sheet; it's in Chinese, but the important information is there. Start by checking the DC voltages. First, find a good connection point for the circuitry's 0V rail. Follow the track from pin 7 of either of the NS4148s. It...
  18. KrisBlueNZ

    transformers back to back - why won't work?

    Is that really the only factor that limits the output current?
  19. KrisBlueNZ

    transformers back to back - why won't work?

    The original question isn't whether it will work or not; it's why the output power is limited. Clearly it's because the transformers have a power limit. I'm interested to know what factor(s) in the transformer limit the output power. Obviously the core size is ultimately the limiting factor but...
  20. KrisBlueNZ

    Assistance with Transistor Theory

    I'm still not convinced that it's meaningful to describe a transistor as voltage-controlled. It's certainly true that voltage is needed in order for anything to happen - you need a base-emitter voltage source and a collector-emitter voltage source - but that is just due to the nature of voltage...
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