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  1. kellys_eye

    Help understanding this circuit please

    Quite often the LEDs are multi-die and consist of more than one LED in each package. Have you traced the PCB tacks to determine the actual LED arrangement? It could be three lots of series all wired in parallel - one string each via the 'mosfets' that you claim are such (but probably not -...
  2. kellys_eye

    Class B Viking B-2 Transformer Schematic

    Please don't hijack old threads - a new thread would be just as applicable. Post a picture of your transformer. If you have a test meter you can often measure the primary and secondary resistance - the primary being higher (assuming it's a low voltage secondary transformer that you have).
  3. kellys_eye

    220v AC from genset to 300vDC converter 3000W

    Bridge rectifier and smoothing will stop any 'frequency' issues and the MPPT part of the system (DC input) should take care of the rest. Seems to me like poor practise to go this route though - personally I'd wire the Genset into the consumer unit via the appropriate breakers, ensuring that the...
  4. kellys_eye

    Protecting PCB, multiplexers and MCU in vending machines

    Inductors and ferrite noise suppressors (beads, cores around power leads etc) are commonly used to prevent surges (and interference). Thes might need to be on EVERY lead to/from the ESP32 i/o lines (as well as power - which should really have them regardless). Capacitors won't help in the...
  5. kellys_eye

    PS-LX350H Sony Turntable no motor movement

    Check the fuse on the pcb adjacent to the transformer. Show a close up of same pcb. Many small transformers have internal thermal fuses as well as secondary (external) fusing. If the internal thermal has blown you need a new transformer - unless you're lucky enough to see the thermal on the...
  6. kellys_eye

    Quooker PCB problems

    Assuming you can get a replacement board then that would be the only practical 'repair' solution. Your lack of test equipment and knowledge to use it means your options are limited. Given the age of the equipment and potential dangers from getting it wrong I suggest you just replace the whole...
  7. kellys_eye

    Question SMD capacitors

    Tantalums can sometimes give issues but this is more related to the old 'bead' (through hole) type - can be 'little fire makers' in the right (wrong) situation!
  8. kellys_eye

    Doubt leak CR2032 battery

    Nope - in all my years I've never seen damage by a CR2032. You're much more likely to question the lack of functionality the battery supposedly supplied before it gets so old you question potential physical harm from it. Any time I service equipment that has one I change it as a matter of...
  9. kellys_eye

    problem with the table saw motor. Please help!

    Note to OP - don't take any notice of the above....... Not a lot. New brushes should sort everything (assuming commutator is ok/clean).
  10. kellys_eye

    DIY burglar alarm

    Most likely! But if the OP established that the basic circuit/principle works (sounds detected, noises made) we can expand on the necessary modifications to make it work properly.
  11. kellys_eye

    Battery Charging in Inverter

    What are the IC type numbers? (the two 16-pin devices in the middle of the board). You can often find application notes related to the IC type which can include 'approximate' circuit diagrams that could prove useful.
  12. kellys_eye

    Identify diode (SMD)

    Have you tested the diode first?
  13. kellys_eye

    Wood/Resin Bowl RGB Lighting Question from a Novice

    You can purchase individual LEDs that have a colour change function built right into them. Just apply power and off you go...
  14. kellys_eye

    problem with the table saw motor. Please help!

    Those brushes are 'worn to nubs' and the cause of the sparking. New brushes will be nearly an inch long! As they wear down the spring pushing them onto the commutator looses its 'push' and the 'light touch' the brushes then have create massive sparking. You can even see the erosion of the...
  15. kellys_eye

    Trying to find a new LCD for a Sunny AT 819/4 MP3 player

    Unless it is a 'standard resolution' i.e. 320x240, 400x480 or 640x480 etc then you're probably out of luck. What is wrong with the display you currently have? If it's 'complete' you may have issues with back lighting that could, theoretically, be replaced.
  16. kellys_eye

    DIY burglar alarm

    Looks a plausible solution - try it! But check the connections ot the amplifier module - the input is usually the socket you show going to the speaker and the speaker usually connects to the blue screw terminals. YMMV.
  17. kellys_eye

    problem with the table saw motor. Please help!

    Such motors typically use carbon brushes and they do wear out (sometimes they get stuck in their housing and don't contact the commutator properly). Since they are 'serviceable' parts they are your first port of call to be checked. I doubt you'll need to go further....
  18. kellys_eye

    Basic: Trying to hookup 20v Decker lithium battery - to a 20V four wire Hoover vacuum. Same parent company.

    Fuse? Yes, the controller board would normally have the current limiting circuitry but a fuse in the battery lead is a wise idea. Not sure of its rating as I'm not familiar with the motors consumption. Try a 5A fuse to begin with. If you have a test meter you can measure the UNDER LOAD...
  19. kellys_eye

    Basic: Trying to hookup 20v Decker lithium battery - to a 20V four wire Hoover vacuum. Same parent company.

    If all you want to do is power the motor from the different battery then simply connect the motor TO the battery via a switch. Simple 'on/off' is all you get (no power level changes) and it'll work - always assuming the motor is rated for the battery voltage of course! If you need power...
  20. kellys_eye

    18v to 12v conversion question

    Bit of 'overkill' but yes, it will work. There are many other types of buck (down) converter available and one with a lower power capacity would be smaller and cheaper. Your cooling fan is possibly rated at well under 1A (?) so something like this will do...
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