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  1. KrisBlueNZ

    Line Volume Control Design?

    Sure. Just Google stereo volume control circuit. The articles and images show you exactly what to do. I also looked up "volume control" on Wikipedia and found https://en.wikipedia.org/wiki/Potentiometer#Audio_control
  2. KrisBlueNZ

    Identifying a 0341 regulator?

    Have you tried to find a service manual or schematic diagram for the set?
  3. KrisBlueNZ

    Last night...

    Thanks for the pointers Chris :-) I'm not a huge fan of "In the year 2525", but I agree with you about "Rhythm of the Night". I've always liked the energy, the uplifting feel, and the rhythmic tightness of that song. Some people perhaps think that dance music is a bit shallow - perhaps...
  4. KrisBlueNZ

    Unable to use external clk

    The clock source selection is controlled by five fuse bits: CKSEL3, CKSEL2, CKSEL1, CKSEL0 and CKOPT. See the sections on Clock Sources and Crystal Oscillator for details. These fuse bits cannot be changed by firmware; they must be programmed by the device programmer. The device programmer will...
  5. KrisBlueNZ

    Trying to fix home subwoofer amplifier. Any help is appreciated.

    It's interesting that the one from the other side isn't showing any signs of damage. It could be that the bad one went faulty internally by itself. It could also mean that there's a separate fault in that side. Proper replacement caps will be bigger than the originals but I'm sure you can find...
  6. KrisBlueNZ

    Last night...

    Chris, thanks for those links! I'm a big fan of that song. There's something special about the slow chord progressions on the organ that I can't explain. The simplicity of the song reminds me of 'Baby Can I Hold You' by Tracy Chapman. Not similar in style at all, but similarly beautiful in its...
  7. KrisBlueNZ

    reparing Receiver - TX-8511

    Didn't you read duke37's reply? As he said, it could a dirty switch. Or maybe dry joints on a switch. Could be the A/B switch or the 4/8-ohm switch, or both. To find out which, put a continuous signal through the amp and tap or gently push each switch in various directions, to see whether one...
  8. KrisBlueNZ

    4536 Programmable Timer question

    Right. 256 seconds is 4 minutes and 16 seconds. That's the total cycle duration at Q24. So from reset, Q24 will be low and will remain low for 2 minutes and 8 seconds, then it will go high for 2 minutes and 8 seconds, then it will return low and the cycle will repeat.
  9. KrisBlueNZ

    Head scratching fault.

    It seems odd that the backlight comes on for a few seconds then turns off, with a new inverter board. I guess it could be a problem with the CCFL tube that causes the inverter to detect a problem and shut down... Have you checked for compromised insulation on the CCFL connections? Run it face...
  10. KrisBlueNZ

    4536 Programmable Timer question

    Every Qn output is half the frequency of the previous one, Q(n-1). With a 32.768 kHz clock, frequencies will be: Q1: 16384 Hz Q2: 8192 Hz Q3: 4096 Hz Q4: 2048 Hz Q5: 1024 Hz Q6: 512 Hz Q7: 256 Hz Q8: 128 Hz Q9: 64 Hz Q10: 32 Hz Q11: 16 Hz Q12: 8 Hz Q13: 4 Hz Q15: 2 Hz Q16: 1 Hz Q17: 0.5 Hz (one...
  11. KrisBlueNZ

    Inductor - 4 Pins???

    Yes, that's the kind of inductor to use in a switching power supply. It will be fine at 100 kHz. Don't worry about the fact that the frequencies specified on the Farnell page aren't 100 kHz. The Q test frequency is just the frequency they used to measure the Q (quality factor) of the inductor...
  12. KrisBlueNZ

    Inductor - 4 Pins???

    To my knowledge, none of those statements is correct. The common-mode choke is designed to have equal and opposite currents flowing in the two halves. This prevents the core from saturating, so it remains inductive and is able to present a relatively high impedance to high-frequency common-mode...
  13. KrisBlueNZ

    westing house tv works but smells of smoke

    Right, I figured it would go all the way through. It's a big burn-up. You'll need to reconstruct the track without any fibreglass to attach it to. I don't think that will be a problem. I've never done it before on a circuit of that type. High-voltage circuitry, yes, but not CCFL drive, which...
  14. KrisBlueNZ

    westing house tv works but smells of smoke

    OK, the caps are Capxon KF (105 degrees Celsius), 1000 uF, 10V. Dimensions are 10 mm diameter, 16 mm length, with radial (PC mount) lead style. Capxon are a known poor-quality brand. I would replace any other large Capxon parts on the board as well. According to the data sheet those parts are...
  15. KrisBlueNZ

    westing house tv works but smells of smoke

    I doubt you'll find the transformer locally. They are a specialist component. Re the capacitors, if they're electrolytics, do you know if they're low ESR? If so, you'll need to replace them with low ESR electrolytics too. If you're not sure, post all of the markings and I'll look up a data sheet.
  16. KrisBlueNZ

    westing house tv works but smells of smoke

    OK. I got a replacement CCFL transformer once from a company called lcdparts.net. They may also be able to sell you a complete inverter board, which will save you from repairing it, though it will cost a lot more than a transformer. The board seems to be a Darfon B070-401. That doesn't seem to...
  17. KrisBlueNZ

    westing house tv works but smells of smoke

    Yep, that's a nasty burn-up. You'll need to remove every bit of discoloured PCB and re-make the connection from the transformer secondary pin as I said in post #5. See if you can clean the transformer using isopropyl alcohol. Be gentle with it and hold it in a folded-up paper towel. Oil from...
  18. KrisBlueNZ

    westing house tv works but smells of smoke

    OK. I can't tell anything more from those pics. I would like to see the underside of the transformer, and closeups of the burnt-up area on both sides of the PCB.
  19. KrisBlueNZ

    westing house tv works but smells of smoke

    I see it. I don't think it's a problem. How about the other transformer? Is there any blob on that? I'd like to see the underside of the transformer above the burn-up. If there's no visible damage there, I wouldn't worry about the blob. Is it possible the blob has dripped onto the transformer...
  20. KrisBlueNZ

    westing house tv works but smells of smoke

    Post a photo. Also if you've removed the transformer, post photos of both sides of the PCB in the burnt-up area, and the underside of the transformer.
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