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  1. kellys_eye

    Switch help

    The relay driver board is the ONLY way you'll get to do it as 'plug'n'play' - anything else would mean using a soldering iron.
  2. kellys_eye

    DIY automated power transfer switch

    This is the crux of the matter - this isn't about switching phases or supplies, this is about disconnecting the 'on peak' meter when 'off peak' tariffs are available. You need to take care over this as the off peak meter usually has a lower current carrying capability (not always). It may also...
  3. kellys_eye

    Cant understand the Zener diode value code

    The number after the 'C' is the voltage..... your example shows C10 - a 10V zener. If it is followed by a 'V', this represents a decimal point. So C6V8 would be a 6.8V zener.
  4. kellys_eye

    Switch help

    Look for a relay driver board for the Arduino. http://arduinobasics.blogspot.co.uk/2014/09/relay-module.html Using discrete components, this can be done with a resistor, transistor diode and relay. The relay contacts, being totally isolated from the rest of the circuitry, can power 'anything'...
  5. kellys_eye

    WACOM Cintiq 21UX - LCD issue

    Tried a replacement video lead yet? <edit> Hellas makes a good point re the backlight coming on, but briefly.....
  6. kellys_eye

    WACOM Cintiq 21UX - LCD issue

    I can see a connector that shows 'backlight circuit' going off to ???? the board I need to see!
  7. kellys_eye

    Comedy Thread

    I treasure the Epipen my mate Dave gave to me with his dying breath. He seemed very insistent that I should have it.
  8. kellys_eye

    Axiomet AX-588 Resistance calibration

    Best method would be to mark all pots with their current position and then start 'tweaking' to see which one has an effect on the meter movement.
  9. kellys_eye

    Help identifying a SOT23 part

    That's the problem - if it was programmed as an input (ADC) port then it's possible it's a clamping zener to protect the input. If it was an output port I'd expect the SOT device to have a load resistor connected to Vcc in its collector (or in the emitter to ground) - indeed it would have a...
  10. kellys_eye

    Obsolete Part Datasheet DZ71100

    Very decent of you. Thanks.
  11. kellys_eye

    RS422 to RS232 converter.

    you answered yourself.... 'True' RS232 uses a ± supply (generally 12V) but that's quite rare these days - note the legacy -12V supply line on some PC power supplies - but TTL level is more prevalent now.
  12. kellys_eye

    Custom Power Supply

    Q1. not really - there is no facility to 'balance' the loads. Q2. common grounds are necessary as you state. If you modulate the LEDs are you quite sure your requirement is for 20A? Have you multiplied out the LEDs per-foot/amperage figures to determine exactly what you need? - although...
  13. kellys_eye

    CNC Plotter with DVD stepper motors

    Gluing a heat sink on would work - alternatively you could solder copper 'fins' to the pins to achieve the same effect as the copper pcb lands.
  14. kellys_eye

    RS422 to RS232 converter.

    There isn't one because you'd have to 'choke' the RS422 signal (10Mb/s) back to under 1Mb/s for the RS232 to work. Not to mention the multi-drop facility..... If you wanted one I suspect you'd have to use opto-couplers to maintain the system balance and the opto-couplers outputs simply switch...
  15. kellys_eye

    WACOM Cintiq 21UX - LCD issue

    My bad... that looks like the screen digitizer board. Need a better (in focus) image of the whole setup to determine which is which.
  16. kellys_eye

    WACOM Cintiq 21UX - LCD issue

    Backlight failure is the usual suspect. If you hold a torch to the screen you may be able to see the image..... It could be thebacklight driver board or the backlights themselves - the former being repairable, the latter 'is' repairable but often sourcing the CFL's is difficult although there...
  17. kellys_eye

    CNC Plotter with DVD stepper motors

    Define 'hot' - but yes, those devices do warm up and quite considerably if the coil currents/voltages are high. Most modern stepper controllers will 'disable' the drive (the motors don't move if the drive voltage is removed but you do need to consider any potential holding torque requirements)...
  18. kellys_eye

    Custom Power Supply

    Can you power the LEDs in smaller strings to make it a multiple-supply situation or do you want 'all your eggs in one basket' from a single source? Given you link to a $300 PSU as a potential solution, what is your actual budget? Computer PSU's CAN be used to drive a PWM source - you aren't...
  19. kellys_eye

    Help identifying a SOT23 part

    Got any more details on the board, its schematic and/or its function?
  20. kellys_eye

    Custom Power Supply

    Whilst China isn't my first choice of destination..... eBay is chock full of examples of 20A+ SMPS systems like this: http://www.ebay.co.uk/itm/Universal-12V-24-360W-2-5-10-20-30A-Switching-Power-Supply-Driver-for-LED-Strip-/222316447845?var=&hash=item33c317c865:m:mhU16LOJEyhyChwdfXTojWQ But a...
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