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  1. kellys_eye

    Sallen Key Low Pass Filter, bandpass filter

    Use any suppliers to show their op-amps via their parametric filter. Just select the parameters you want (i.e. package type, number of internal op-amps, supply voltage, bandwidth etc etc). You can narrow down the list to 'anything' that suits. Look for the spec of the LT6023 (datasheet) to...
  2. kellys_eye

    Starting from scratch

    Don't mess with AC voltages. Use a simple battery laser line generator and fit a 'one shot' delay to it such that pressing the run button (trigger) operates the laser for whatever-seconds you need. The battery in the laser will likely last as long as their shelf-life given the infrequent use.
  3. kellys_eye

    Construction techniques and watch-out lpoint

    Far too complex a subject to be covered by 'comments' on the forum. There will be a plethora of books on the subject and undoubtedly some good website resources if you care to look. Ever heard of Google? (other search engines are available)
  4. kellys_eye

    What did I do wrong in my first project?

    24VAC input rectifies to around 35-36V DC after smoothing. Those regulators are right at their DC limit for input voltage and could be suffering as a consequence. As above, no way am I opening an unknown zip file. Post the pics.
  5. kellys_eye

    7486 IC problem

    You can directly drive an LED using the logic level output of that gate but not a motor. The device you showed in your first post is probably destroyed now since you used a 9V battery with it.
  6. kellys_eye

    Can this PCB be repaired ?

    The corner of the board (broken off) forms part of the ground circuit. Glue (epoxy) the board together and scrape off some green lacquer and solder a wire link between the two copper traces (over the crack). Without seeing the whole board I cannot comment further - it may be that the ground...
  7. kellys_eye

    Unknown PSU switch.

    That looks like a washing machine control board. Remove the relays and wire directly to the coils, using the contacts how ever you want. The power supply components are the transformer (top of the board) and the three items to its right, a bridge rectifier, smoothing capacitor and U1. Remove...
  8. kellys_eye

    Woo-Woo traversable wormholes and invisibility cloaks

    Straight to the 'woo-woo' section with this please.
  9. kellys_eye

    Not sure what sensor to use

    Going to have to be a large(ish) dice if you want to get the part in and not have a cable leading from it.
  10. kellys_eye

    Speaker Amp Module Repair

    Heck, no need to apologise..... I admire your enthusiasm and desire to 'have a go' and that's a positive we don't see enough of these days. It's not as if 'we' aren't prepared to help in any way we can but past experience tells me that this could be a long drawn out process and whilst that...
  11. kellys_eye

    Speaker Amp Module Repair

    Is this how you received the unit? or did you dismantle it yourself? Either way there are a substantial number of components that rely on heat sinking and some (many/all) might require insulating washers between themselves and the heat sinks they mount to. Failure to do so will result is a...
  12. kellys_eye

    Speaker Amp Module Repair

    The 'bottom' capacitor of this cluster looks to be defective and the probable cause of any issues with it. Potentially..... it's the ONLY thing wrong with it. But it might be wise to change all three.
  13. kellys_eye

    Goodmans Record Player in case

    Can you report the device number of the blown IC? Just curious to know what it actually was.
  14. kellys_eye

    Vintage Yamaha Psr 32 Music Keyboard Noise

    If it's as old as that then you really should check or change some capacitors in there. It's a common issue and there is no cure other than replacement parts (assuming that's the eventual issue - quite likely).
  15. kellys_eye

    Vintage Yamaha Psr 32 Music Keyboard Noise

    No. Potentially a power supply issue. Also the possibility that decoupling capacitors have failed somewhere.
  16. kellys_eye

    Crock pot modification

    Heat is a relative concept. You're unlikely to be able to keep a finger on something that's over 60degC let alone anything higher. Nothing wrong with that. I didn't know if the OEM pot allowed temperature control - seems like the digital display is for time only then? You will, of course...
  17. kellys_eye

    Crock pot modification

    Fairly complex electronics for such a simple function as heating therefore the use of PID seems likely. On the plus side there's no relay (the heating element is controlled by a triac) so any high-side switching issues will be down to the triac being faulty - assuming the digital display and...
  18. kellys_eye

    Goodmans Record Player in case

    That knackered IC is an audio amp and potentially a Class-D type that runs on the main 5V rail supply. Before replacing it you could check that audio is being passed TO that device to ensure there's nothing else in the signal path that is dud.
  19. kellys_eye

    Connecting aerials together to boost mobile signal?

    Aerials can be simple or complicated depending on how you analyse their function. From a basic isotropic radiator (null gain) to highly directional ('focused') multi-element devices with many dB of gain it's a dark art to some - many in fact. You can increase gain but this introduces...
  20. kellys_eye

    Crock pot modification

    Always difficult to be helpful considering we also need to take heed of personal safety and don't know of your skillsets or level of competence to task working with potentially fatal voltages. That said, you seem to have your head screwed on the right way around and look to be approaching this...
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