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  1. kellys_eye

    my busted psu

    No. Yes, it did - caveat - if you read it and understood what was being said.
  2. kellys_eye

    Wiring question on electric bike

    We might as well toss a dice or pick colours at random to give you an answer to this! You supply no information at all. No bike make/model, no throttle make/model, no pictures (300kb max upload here). Without something to go on other than a list of colours we aren't psychic!
  3. kellys_eye

    Can someone help me identify this electronic component

    The device in the centre of the push switch contact pads looks to be an LED - potentially bi/multi coloured. If that's the case then the CoB was used to change its colour at each key press, illuminating through an opaque push button pad. Crystals are normally a requirement for controls that...
  4. kellys_eye

    my busted psu

    Which one? If you aren't using the correct schematic you are wasting your (and our) time trying to reference anything and making assumptions from any tests you make. Post a picture of the circuit board itself and we might be able to get more info for you.
  5. kellys_eye

    capacitor replacement help

    Back on topic (I think!) - if you want to test your changes to LC or R then you will need some pretty sensitive equipment to tell the microscopic differences that will result. Audio spectrum analyser, distortion meter and all with specs of sub 1% accuracy (0.001% probably). There's no...
  6. kellys_eye

    Can mosfet driver supply continuous current of 2Amps?

    Rds(on) is 120mΩ (at 4.5V Vgs) so passing 2A will dissipate around 0.5W. The package is rated at 1.25W so you're well within the recommended limits therefore it should last indefinitely.
  7. kellys_eye

    capacitor replacement help

    Yes, 2.7mH. Not sure what else you want to know! It's a coil!
  8. kellys_eye

    BJT AC Analysis - feedback pair equivalent circuit

    Q1 is a PNP transistor so you drive its base negative with respect to the emitter to cause it to conduct, this 'negative' drive shown as opposing flow hence the arrow direction.
  9. kellys_eye

    Generating 24VAC Output (2 Amp Capability) from 36-40VDC

    ...and the OP is driving solenoids with them.....
  10. kellys_eye

    1602 Display Problem

    Manufacturing differences mean they have to include a contrast adjustment and using a fixed resistor for a 'mass produced' item gives rise to the odd device not having the right value due to those differences. Remove R1 and fit a preset pot (10k) or slap in a higher/lower value to see the...
  11. kellys_eye

    Help repairing car stereos: Delco 90's CD & tape player

  12. kellys_eye

    HAM Radio Relevance Currently and Personal Reflections.

    Being a pedant...... No, it never was - you didn't have to become a ham. Prior to radio communication people wrote letters. Then they had typewriters and the printing press. Scientists collaborated across the globe using hand writtten letters, Governments ran Empires the same way. None of...
  13. kellys_eye

    Generating 24VAC Output (2 Amp Capability) from 36-40VDC

    17V positive and negative.
  14. kellys_eye

    HAM Radio Relevance Currently and Personal Reflections.

    Everything is a learning experience and there's nothing more satisfying (to me anyway) than learning something new or understanding how something works. A blind acceptance of 'things' is ok if you want to stay uninformed. Knowledge has no bounds but it does have 'value'. Inestimable imho...
  15. kellys_eye

    capacitor replacement help

    There are some very cheap and relatively accurate devices for measuring components - a few quid from your local Chinese Emporium (i.e. eBay) but if you are adventurous you could try to determine it using the core size (width, height, layers, wire diameter) assuming it's air-cored. Such formulae...
  16. kellys_eye

    Help repairing car stereos: Delco 90's CD & tape player

    Ahhh, that's called a VFD (Vacuum Fluorescent Display) and is solidly mounted and driven by the dedicated multi-pin chip under it. The only potential issue I can see is corrosion (or deposits) on the solder side where the white connector is. Clean that up using IPA (solvent) and potentially...
  17. kellys_eye

    5V Computer Fan - easy way to reduce speed?

    There is no practical way to determine rpm using resistors to limit the speed. Suck it and see is the way to go here. Even the airflow path resistance will mean a change in resistor value (i.e. you might slow it down 'on the desk' under testing but when the fan is placed in a path that offers...
  18. kellys_eye

    capacitor replacement help

    Look up the word 'audiophoolery'
  19. kellys_eye

    1602 Display Problem

    There should be a small potentiometer (perhaps with blue body and tiny brass adjustment screw on it - might just have a simple screwdriver slot) situated under the display somewhere. Give it a 'spin' with a small screwdriver whilst watching the display.
  20. kellys_eye

    Generating 24VAC Output (2 Amp Capability) from 36-40VDC

    So what else is it powering? This can mean the difference between a 'simple' AC source and a complex one. Any answers may be wasted effort unless we are fully informed. I feel that there is a lot of information we aren't getting here and it doesn't help.
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