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  1. kellys_eye

    Unidentified tantalum capacitor

    The only proper test for electrolytics (or tantalums) is for ESR - if their value is within tolerance and their ESR reads acceptably then they are good-to-go. This measurement can only usually be achieved out-of-circuit. Your main issue will be the capacitors BEHIND the tants as they look...
  2. kellys_eye

    Capacitor value query

    Again
  3. kellys_eye

    Capacitor value query

    Right
  4. kellys_eye

    Weird coil latching problem

    Nope - it's the 1N400* series
  5. kellys_eye

    It's about Protel 99 SE SP6

    Reload Protel and the files should be restored.
  6. kellys_eye

    Design a short circuit protection for +15/-15 and +10/-10 DC power rails

    It doesn't work like that. Excessive current can only be DRAWN through a device - you can't 'force it in' to a device. Only by shorting the 7810 output can it be made to 'overload' - but it has built-in thermal overload and internal current limiting so that's out of the question. I note R155...
  7. kellys_eye

    Add buzzer to this circuit

    OK, I assumed there were spare lines according to the 'incomplete' schematic but either way, connecting your buzzer across any of the outputs will make it sound.
  8. kellys_eye

    Capacitor value query

    Right
  9. kellys_eye

    Add buzzer to this circuit

    Chose a suitable buzzer (seems like the power rail is 15V so something aorund that operating voltage will do - you can use a 12V version with a dropper resistor but you'll probably get away with straight connection to 15V in this case). Connect the '+' side of the buzzer to the +15V rail (top...
  10. kellys_eye

    Hunter Ceiling Fan Receiver

    Only the electrolytics and large (yellow) PP capacitors need checking. Not in this case - it will be a device called a DIAC. Possibly - the waveforms aren't sinusoidal at every pin (changes shape with light level setting) and your meter might not be good enough to sense the difference. You've...
  11. kellys_eye

    Yaesu FT75 manual/schematic required

    Well, well, well.... I've been contacted by an amateur radio guy here in the UK who not only has NOS copies of the manual but various sets and spares/accessories!!! From 'zero' to 'hero' in the short time of a few hours. Never had so much luck! If this thread proves useful to others (I will...
  12. kellys_eye

    Yaesu FT75 manual/schematic required

    Yup, been there, done that. Joined their group too - they might have more 'inside' - but still waiting approval for membership.
  13. kellys_eye

    Yaesu FT75 manual/schematic required

    As per the title - anyone got one or anyone know where I can download one? The FT75B is readily available but the FT75 is an earlier model radio with significant differences that make the FT75B document 'difficult' to use. This is the unit mentioned: https://www.rigpix.com/yaesu/ft75.htm TIA
  14. kellys_eye

    Design a short circuit protection for +15/-15 and +10/-10 DC power rails

    The schematic you provide doesn't match the burned components you show. We really can't comment on why parts burn out unless you give more details. I suspect (but can't actually prove) that some enterprising student connects an AC voltage to the DC output - is this possible(?) - I'd say yes...
  15. kellys_eye

    Timer circuit

    Assuming zero losses - radiative etc
  16. kellys_eye

    Timer circuit

    Cheap and cheerful - use a thermostatically controlled bath tap and feed cold water and the solar to it and set it to whatever temperature you want. It's a circulatory system isn't it? Doesn't matter of the water going in is too cold as it will warm up when the sun shines!
  17. kellys_eye

    UART communication between RPI Pico W and Arduino Nano

    The data path is bi-directional so you'll need level changers for both directions unless the Nano is happy discerning logic levels that 'only' rise to 3.3V (high) which, for most devices, is acceptable but, depending on the application (speed notwithstanding) may introduce errors. To do the job...
  18. kellys_eye

    Timer circuit

    What has the volume got to do with it? The way you describe the situation you'd need to regulate the Sun.... You can't adjust the volume without adjusting the outlet temperature - slower=hotter, faster=cooler. 'Holding' water in the system until it reaches the desired temperature just...
  19. kellys_eye

    Need Help with my PS5 controller! [DRIFT]

    Somewhat ambitious to consider Sony would monitor the content of this forum - but you never know.... Have you checked out Youtube for solutions? I've seen a few.
  20. kellys_eye

    Texas instruments - 1705

    What are you using for a clock signal and how is it connected?
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