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  1. kellys_eye

    Ultrasonic Cleaner Isonic P4820 not working

    Classic case of 'shouldn't have touched it' and returned it under warranty. Sure the transducer is in contact with the base? If it's not then the sound waves certainly won't make the 'air gap' jump. Silicon doesn't help either UNLESS the transducer is securely fixed to the base as it will...
  2. kellys_eye

    Help copying program from C167CR Chip

    I note the device is available as mask-programmed ROM or for external memory. Perhaps yours is masked ROM? Certainly would be the case for a mass-produced item. In which case you've no chance.
  3. kellys_eye

    Testing Oddball MOSFETs

    Seriously? Invest in one of those cheap Chinese electronic component testers. They are invaluable for simple tests, checks and basic measurement of all types of device and MOSFETs are included. They identify pinout, go-nogo status and basic device parameters. Just randomly connect the three...
  4. kellys_eye

    Dc switch

    Not normally, no. There's no requirement to switch the positive AND negative wires except where a split-rail supply (positive - ground - negative) is employed. Occasionally it is done to secure total supply isolation. What are you powering?
  5. kellys_eye

    Old Resistors

    Usually the LAST band is silver, gold red or brown (10%, 5%, 2% and 1% respectively - tolerance) but a multimeter is sometimes the easiest way to get it right. Wattage is a 'physical' thing and best determined by length/width and comparison to similar resistors. Most suppliers will have...
  6. kellys_eye

    Help copying program from C167CR Chip

    I don't see any reference to software protection within the device - maybe it's only noted in the programmer documentation? - but if there isn't any implemented then you're going to have to jury-rig an adapter. Do you have access to the software used to program a device?
  7. kellys_eye

    12vdc relay

    Doesn't that mean there is power to the Arduino board? Are the Arduino/relay adjacent to each other? A block/wiring diagram would be useful.
  8. kellys_eye

    12vdc relay

    Do you have any supply at the destination end (what's the relay powering?) If there is one then use a transistor at the relay end to boost the current (signal in at the base via a resistor, relay in the collector circuit, ground the emitter).
  9. kellys_eye

    Get your tin foil hats out....

    Seems like the tin foil hat association has more members than I reckoned on! https://hackaday.com/2018/01/07/go-retro-to-build-a-spectre-and-meltdown-proof-x86-desktop/
  10. kellys_eye

    Transistors

    An old electronics magazine used to have a basic transistor use methodology that defined them as TUN or TUP, Transistor-Universal-N(PN) or P(NP). They specified basic minimums for Vce, Ic, Ptot and gain etc and they showed many circuit designs where the specc'd transistor was simply TUN (or...
  11. kellys_eye

    LCD for mp4 player module ?

    Do you know what format the video signal on your connector actually is? Get it wrong and you're buying blind, potentially wasting your money.
  12. kellys_eye

    Motherboard Power

    You mean you want a laptop then......? That's what you're making and there are laptops already that are as powerful (some more so) than desktop machines - certainly when compared to desktops of only a few years ago. What do you need this computing power for? What will you be running that...
  13. kellys_eye

    RF Transmitter/Receiver Without Arduino?

    Nearly all transmitters will require a digital signal of some form - unless you build your own - therefore the requirement to encode and decode is going to be an integral part of the system hence the use of an Arduino (or other similar) device. You can get simple powered mains sockets...
  14. kellys_eye

    New to electronics. Toaster Oven disassembly question

    Looks like those elements have had connections 'spot welded' to them. They will have to be cut off and the sides of the box bent apart to allow one end to be removed before pulling the whole element out. Your problem will then be reattaching a connection as the element wires will most likely...
  15. kellys_eye

    Output voltage is higher than it should be

    Note that they are high speed rectifiers and you cannot use an ordinary silicon diode.
  16. kellys_eye

    Reversing polarity

    Yes you can. But you need limit switches at the end stops of the travel and a switch to determine the direction of motion.
  17. kellys_eye

    Calculating gyroscope turn regardless of angle

    Link to datasheet?
  18. kellys_eye

    Output voltage is higher than it should be

    Definitely defective, change it. Change them ALL if you want continued reliability.
  19. kellys_eye

    Woo-Woo Free Energy From Pulsed DC Transformer

    Stop wasting your own time and ours. (that's genuine 100% constructive criticism)
  20. kellys_eye

    Wanting help fixing bench power supply.

    Any decent PSU will have protection from 'reverse feeding' a supply INTO it - this could be as simple as a transient absorber or a reverse connected zener across the output. Either way it's gone short - the current operating symptoms you describe clearly indicate this. Show a pic of the...
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