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  1. KrisBlueNZ

    Capacitor and fuse blown in audio amplifier (integrated in active speaker)

    OK. A good starting point would be a Google search for power amp module. You could add kitset to those search terms if you want to build it yourself. I found an image search was helpful as well, but I guess you need to know what you're looking for. You should be able to find a suitable product...
  2. KrisBlueNZ

    How to get a strong signal over a long distance

    You want to transmit on a band that's used for cellular communication? That would be illegal. Or do you want to transmit it through a cellsite? Because that's an option; you can get GSM data modems that accept a SIM card, like a cellphone, and can transmit and receive data on the internet, if...
  3. KrisBlueNZ

    Capacitor and fuse blown in audio amplifier (integrated in active speaker)

    I would replace them all, in both channels, but they're probably not the only semiconductors that are damaged. Normally when these amplifiers fail like this, ALL of the semiconductors in the output stage are damaged. And replacing them doesn't necessarily fix the problem - it could have been...
  4. KrisBlueNZ

    Capacitor and fuse blown in audio amplifier (integrated in active speaker)

    OK, TL072 is a common dual op-amp. 8707 is the date code - 1987, 7th week. So the amplifier is probably around 25 years old. Do you have a multimeter? While you have the transistors uncovered, you can see whether they're short-circuit. Most likely at least one of them will be. Measure...
  5. KrisBlueNZ

    Capacitor and fuse blown in audio amplifier (integrated in active speaker)

    Those four little boards screwed to the metal are the output transistors. Can you try to get pictures of them viewed from above? Or at least read the markings on them using a mirror? Also can you post either a picture, or the markings, on the 8-pin IC near the front of the main board, about 1/3...
  6. KrisBlueNZ

    How to get a strong signal over a long distance

    That makes sense to you, but it doesn't tell us very much at all. Where is the image stored? What format is it in? Are you using a microprocessor to access it? What do you want to do with it at the other end? Do you have a microprocessor there as well? And don't just answer those questions. Do...
  7. KrisBlueNZ

    Guitar amp foot switch question

    Hmm. Can you find out whether the socket on the amp is mono or stereo? You might be able to see into it with a bright light, otherwise you might have to open it up. A double footswitch with a mono plug would probably work by having different resistances in series with each switch. If your...
  8. KrisBlueNZ

    Capacitor and fuse blown in audio amplifier (integrated in active speaker)

    Hmm, you're right. I can't find much at all on it. How old is it? Can you upload some more photos? Start with a view of the complete unit, from above and below, then closeups of both sides of the board.
  9. KrisBlueNZ

    Help me understand my scope trace result on a IR photocoupler.

    Can you post a picture of the disc, and a few pictures of the photointerrupter from different angles? How many connection points does the photointerrupter have? What have you connected to each point? Can you post a diagram of how it's connected? Do you have a pullup resistor on the output, or...
  10. KrisBlueNZ

    Scoreboard Project

    Yep, I'll take this to email.
  11. KrisBlueNZ

    Capacitor and fuse blown in audio amplifier (integrated in active speaker)

    It would be helpful to know the brand and model number, so we can try to find a service manual, or at least a schematic diagram.
  12. KrisBlueNZ

    Scoreboard Project

    Well, EEPROM just means electrically erasable PROM, so Flash ROM is a type of EEPROM, but EEPROM is usually used to describe serially accessed devices in compact packages. Here's a Flash ROM that would work: the Macronix MX29F200CxMx at...
  13. KrisBlueNZ

    Scoreboard Project

    I guess you mean Flash ROM. It's technically a type of EEPROM but EEPROMs normally have a serial interface. You could use Flash ROMs but they have data widths of 8 or 16 bits, so you would need either 7 or 14 of them, and you would only use the first ten locations, and waste the other 65,526...
  14. KrisBlueNZ

    Scoreboard Project

    Another possibility is a diode matrix. Convert your 4-bit BCD number to a one-of-ten output, and use diode ORs to generate your thirteen "segment" control signals. Suitable BCD decoders are: CD4028B - your best option, with ten active-high outputs CD4514B sixteen active-high outputs CD4067B...
  15. KrisBlueNZ

    power with line wire enter the wall switch and out going and there is no neutral

    I told you what I suggest. Get a professional industrial electrician to install an appropriate switching device in a suitable place such as a switchboard where Neutral is available.
  16. KrisBlueNZ

    power with line wire enter the wall switch and out going and there is no neutral

    I know there's no Neutral wire in the switch recess. I don't think you should be installing the switching device (whatever it is) in the switch recess. A qualified industrial electrician would not do that. He would install it on the switchboard, or somewhere similar, where Neutral connections...
  17. KrisBlueNZ

    power with line wire enter the wall switch and out going and there is no neutral

    moeinglory, I'm sorry, I've changed my mind about this project. I don't believe this project is safe and I will not be involved with it. This is what I recommend you do. Get a qualified industrial electrician to install a suitable switching device that can be controlled by a low-voltage control...
  18. KrisBlueNZ

    auto restart in the event of a power failure

    Sorry Oliver, I don't want to get involved. You should be able to guess why. If you really didn't follow the discussion on safety, I think you should!
  19. KrisBlueNZ

    power with line wire enter the wall switch and out going and there is no neutral

    I'm working on a schematic now. In the meantime, can you please answer these questions: Can you give me some information on your remote control receiver? What are the characteristics of its output? How much room is available for your circuit? Does it have to fit inside a switch recess? Will it...
  20. KrisBlueNZ

    power with line wire enter the wall switch and out going and there is no neutral

    Your wireless receiver needs 300 mA? That sounds like an awful lot. Can you put your location in your profile?
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