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  1. KrisBlueNZ

    stereo capacitors

    Yes. It's not a normal cylindrical glass fuse. It's a thermal fuse. It is marked with its rated temperature, 135 °C. It may or may not be replaceable. Once you've confirmed that it's open circuit, you can start unwinding the tape off the transformer to see whether you can find the wires that...
  2. KrisBlueNZ

    stereo capacitors

    OK, but the rest of the unit is dead? It could be the thermal fuse, which is shoved inside the transformer. If the transformer gets too hot, the fuse opens and stays open, and you have to replace it. Unplug the unit from the AC mains, and measure the resistance across the two pins of the mains...
  3. KrisBlueNZ

    stereo capacitors

    I've found a sevice manual, but you're going to need at least a multimeter to diagnose it. You can pick one up for under $20. Actually you can get one for under $10 on eBay. They won't be very good quality but they're adequate.
  4. KrisBlueNZ

    74hc238 binary decoder info

    You're not supposed to rely on that. Though designers usually do :-)
  5. KrisBlueNZ

    stereo capacitors

    Hi there and welcome to Electronics Point :) Are you worried about the two big electrolytics with the brown goop around them? It's probably just a kind of glue they use to hold it to the board. It looks like there may be some discoloration on the underside of the board but it's hard to tell...
  6. KrisBlueNZ

    Timing Circuit? Counter?

    Yes. Almost all of the heat your regulator has to dissipate is due to the product of voltage dropped across it and output current. So you CAN'T use a SOT-23 regulator. You NEED a regulator that has a metal tab, large enough to be heatsinked in this way. It will waste a bit more power than a...
  7. KrisBlueNZ

    Timing Circuit? Counter?

    Regulators with higher current capability generally have higher quiescent current as well, so they will waste a bit more power than smaller ones. In this case the problem is not the output current, it's the power dissipation. As I explained in post #28 (towards the end), power dissipation in a...
  8. KrisBlueNZ

    PLL (CD4046) FOR 50Hz

    R2 isn't needed. What value is R1? 320E? Does that mean 320Ω? If so it's much too low. Try multiplying the resistor value by ten and dividing the capacitor value by ten. The rest of it might be OK. You haven't given enough information to be sure. But even if you did, I couldn't tell you for...
  9. KrisBlueNZ

    Introducing Myself

    Welcome to Electronics Point :-)
  10. KrisBlueNZ

    Nixie Clock

    No. Hey, I have a question... HAVE YOU REPLACED THE MC34063s ???
  11. KrisBlueNZ

    Harman/Kardon HK6500. Loudness not working when button is pressed

    Right, the NTE55 and NTE377 are TO-220 packages - the flat type with the tab at the top for mounting on a heatsink. These are always BCE pinout (at least, I've never seen any exception in 30+ years) so there's no problem there. They are in the right way. Yes, the eight transistors that are...
  12. KrisBlueNZ

    74hc238 binary decoder info

    "... connected but turned off..." doesn't mean anything. Also the input and output pins on the HC238 are not GPIO. Each one is defined as either an input or an output by the design of the device. Inputs on HC devices have a very high impedance and will float to random states if they are not...
  13. KrisBlueNZ

    Finally got me a 'scope - Have some questions

    This can be caused by failure of high-voltage resistors that set the voltages on the grids in the CRT, including the resistors connected to the brightness control potentiometer.
  14. KrisBlueNZ

    Harman/Kardon HK6500. Loudness not working when button is pressed

    I mentioned pinouts in posts 65 and 110 where I was suggesting replacements, but I didn't explain what they were. I didn't suggest using the NTE devices - I said I didn't recommend them. Whoever suggested them should have pointed out the differences. I guess they probably are in wrong. I don't...
  15. KrisBlueNZ

    Trying to solve a 12v D.C. Problem, Need Help

    It might be your only solution, or your cheapest and simplest solution.
  16. KrisBlueNZ

    Harman/Kardon HK6500. Loudness not working when button is pressed

    No. Where are Q531 and Q532? I can't seem them in the parts list. I mean that all the TO-92 transistors that look like either one of these pictures. The originals have the Japanese pinout, which is E-C-B looking at the flat face with the pins pointing downwards. The replacements have different...
  17. KrisBlueNZ

    Harman/Kardon HK6500. Loudness not working when button is pressed

    Yes you should replace the eight transistors in the power amplifier section, then run it for a while and see how hot everything gets. If those eight transistors are still getting hot, we can measure some more voltages to see whether they are running at the right current or not. How are you...
  18. KrisBlueNZ

    need help for convert mikroc code to bascom avr

    You're probably best to look on a bascom AVR forum. Google bascom avr forum. There are lots of hits. Maybe you will find one in your native language. Good luck!
  19. KrisBlueNZ

    Harman/Kardon HK6500. Loudness not working when button is pressed

    No, that won't make any difference. We just need to remember to keep an eye on that voltage. See if any changes affect it. Adding a fan to the 12V rail would just overload the regulator and make the problem worse! But you could try to find a 110V AC fan and connect it across the main...
  20. KrisBlueNZ

    Harman/Kardon HK6500. Loudness not working when button is pressed

    Thanks for the photos. They're all good but some of them have "bloom" from reflections of the light source. It's best to take them outside in indirect light. But it doesn't matter in this case. I don't think I need to know much about that board. The overviews of the top side are good for giving...
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