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  1. poor mystic

    And now something weird

    A simple and satisfying repair.
  2. poor mystic

    Why no more than 4 batteries in any particular string?

    Hi :) I asked DeepSeek and got this reply: Q: "why should no more than 4 lithium ion batteries be charged in series?" Of course. This is an excellent and crucial safety question. The directive to not charge more than 4 lithium-ion batteries in series using a simple balancing charger is a rule...
  3. poor mystic

    What is the purpose of Q2?

    OK, that's how you want it.... but might not a "fellow contributor", such as the OP, such as myself (and even such as yourself, potentially) ask questions? I'm sure the questions are obvious enough. Firstly the OP wants to know about Q2, and secondly I've proposed an answer, which is also in...
  4. poor mystic

    What is the purpose of Q2?

    :) I keep changing my mind about Q2. The circuit's operation only gradually emerges to me through the murkiest of mists; have I got it right yet? There's already negative feedback around Q1, of course. That's provided by R4 and C7. I can't see Q2 as anything more than active bias from my...
  5. poor mystic

    What is the purpose of Q2?

    I thought that the OP wanted to know about the purpose of Q2 and the stage that it powers. Does it seem to others that it is part of the negative feedback network? (For the OP's sake, if he needs to find this out, a negative feedback network is used to ensure a flat response over a range of inputs.)
  6. poor mystic

    What is the purpose of Q2?

    :) but what are Q2; C2 and D1 for, @Deltaprime? (They still look like active filter feedback to me)
  7. poor mystic

    What is the purpose of Q2?

    Hi and welcome :) Q1 appears to me to be part of a negative feedback loop, which helps keep the output of the amplifier faithful to the input - except that the output is amplified. D1 keeps Q1 in a usefully semiconductive state - that is it's a part of Q1's bias network. I'm thinking that C1...
  8. poor mystic

    Can I use a digital potentiometer/remote volume kit in a vintage Pioneer LX-424 receiver?

    Yeh that was tongue-in-cheek, but I personally do like the idea of a remote-controlled Button Pushing Machine. For me, BPM control has many obvious, real advantages over modifying good equipment that might be damaged in the modification process.
  9. poor mystic

    Can I use a digital potentiometer/remote volume kit in a vintage Pioneer LX-424 receiver?

    :) from what these experienced people are saying it sounds like you might need another approach. So For the sake of cheek ;) what about an external robot arm - a re-purposed aero actuator - a semi-mechanical solution. You can buy remote control toy cars very cheaply...
  10. poor mystic

    Can I use a digital potentiometer/remote volume kit in a vintage Pioneer LX-424 receiver?

    :) from what these experienced people are saying it sounds like you might need another approach. So: For the sake of cheek ;) what about an external robot arm - a re-purposed aero actuator - a semi-mechanical solution. You can buy remote control toy cars very cheaply...
  11. poor mystic

    Can I use a digital potentiometer/remote volume kit in a vintage Pioneer LX-424 receiver?

    :) thanks for the "like" Bundyboy dot dot dot ... please post a photo of the part you need to replace.
  12. poor mystic

    Can I use a digital potentiometer/remote volume kit in a vintage Pioneer LX-424 receiver?

    Hi Bundyboy I'm sure we'll want to see any circuit diagrams you have for the amp. Also please post a good, clear photograph of the inner workings of the amp, showing the part you want to replace. Would you please post those things for us. (edited 10 minutes later) ... I just spent 5 minutes...
  13. poor mystic

    Music that makes you smile

    OK so this music might amaze you for a few moments, before the smile arrives... (and if you liked that then try this: which is maybe not so smiley, but is very grand)
  14. poor mystic

    Using 2 C005 Timer modules for an on-off timer switch, alternatives for timing, low power?

    Hi :) See if you can get some old Forrest Mims books on using digital IC's. something like https://www.amazon.com/Forrest-Mims-Circuit-Scrapbook-Vol/dp/1878707485 would help. You still have to do some thinking and play with some (cheap) IC's PS Some people made a complete hobby out of this...
  15. poor mystic

    Music that makes you smile

  16. poor mystic

    Comedy Thread

    If that is her response to modern life then I have a lot in common with your cat
  17. poor mystic

    power

    See! DP recommends another set of high current sources on the same board. If ya can't beat 'em, confuse 'em. Cheese :)
  18. poor mystic

    How to improve the reliability of RS485 communication?

    :) May I add that you must pay attention to cable routing. Particularly, unterminated stubs can be problematic.
  19. poor mystic

    power

    :) Like, how do you deal with a client with an impossible brief? Ya gotta really need the money, for a start, else you'd take one look and fo. You have to explain. They're always grateful in the end, but it causes bad gutsaches until they know. Keep yr chin up oh yeh PS this sort of thing is...
  20. poor mystic

    Measuring an NST Output

    Hi again Look I really think you need to be talking to electrical engineers. This is a hobby forum. Asking about stuff like that and telling us you know what you're doing. Just don't, please.
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