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  1. kellys_eye

    Switched Mode Power Supply/Switching Power Supply (SMPS)

    Of no concern at this time. Working 'backwards' the terminals marked 8 and 9 on the bottom of the PCB are the secondary windings of the switching transformer and is applied to the anodes of the large rectifier package at the bottom right of the image (on its own heatsink) which then produces...
  2. kellys_eye

    Switched Mode Power Supply/Switching Power Supply (SMPS)

    The board looks to have two distinctly separate SMPS circuits (paths) to generate the voltages - given the two lots of input filters and two 'transformers' - so losing ONE supply is quite possible without losing the other. I can see output current limiting (detection) resistors and two lots of...
  3. kellys_eye

    Stepper Motor problems...

    Can you determine if the step loss is consistent? I doubt this is a motor drive issue. It could be as simple as forgetting that steps count from 'zero' as opposed to 'one' and adding an extra step in the reverse direction may be all that's needed? I.e this is a programming issue. Which...
  4. kellys_eye

    El Panel Brighter

    Manufacturers specify the brightness of E panels at the normal operating conditions. If you want to exceed those parameters then expect to damage the device or significantly reduce its lifespan. If you want a brighter light, use a brighter source.
  5. kellys_eye

    How do I reduce the speed of a 12v childrens car

    There IS no resistance on the throttle pot....... it's an active device, not a passive one. The actual control voltage is the one that varies and appears on the GREEN wire with respect to the YELLOW wire if we accept the OP's tests as given.. Connecting a potential divider across the...
  6. kellys_eye

    Normal resistors for High Voltage application

    Can you let us know what it is you're attempting to do? Where is this high voltage that you are curious to measure?
  7. kellys_eye

    How do I reduce the speed of a 12v childrens car

    Which wires? There are three. Show the voltages (with the wires CONNECTED) between: red-yellow red-green yellow-green yellow-red green-yellow green-red As I stated, the throttle controller is a HALL EFFECT device - not resistive - so we need to adapt to a different method to limit the...
  8. kellys_eye

    Useful download

    Got an email from Rohde & Schwarz today with an offer for a free download copy of Worldwide Spectrum Allocation Chart - requires registering your details bit US/Canada residents may be in line for a free printed copy - and it's just under 7Mb (pdf). 1kHz to 300GHz coverage and 'interesting' to...
  9. kellys_eye

    What are these sections of this power supply?

    You could wire the tube heaters in series and use a 24V 1A secondary transformer (separately from the 250V transformer).
  10. kellys_eye

    How do I reduce the speed of a 12v childrens car

    Hmmm, it seems as if the motor is BLDC and the accelerator is a HALL EFFECT controller if this is the pedal: http://shop.mat-con.net/epages/62158737.sf/en_GB/?ObjectPath=/Shops/62158737/Products/pedal and this is the controller: Please confirm. We might be able to get the technical manual...
  11. kellys_eye

    How do I reduce the speed of a 12v childrens car

    Assuming the sliding bits are actually a potentiometer (and the three wires/plug seem to go to prove this) then all you need do is break one of the coloured wires and add an extra resistor. But WHICH wire to cut? The three wires will connect to the 'top', 'bottom' and 'wiper' of the...
  12. kellys_eye

    Hi, I'm Jacob

    Welcome to 'anyone' who wishes to keep tubes 'current'!!!
  13. kellys_eye

    What are these sections of this power supply?

    T1 is specc'd at 9V for the filament winding hence the regulator and DC drive (also presumed to reduce 'hum'). What 'gets me' is that the secondary amperage is stated to be 2.5A and after Bridge Rectification into a capacitive smoothing circuit the maximum current will be around 1.7A which...
  14. kellys_eye

    How do I reduce the speed of a 12v childrens car

    If the accelerator pedal is operated by a pivoting lever action you can move the pivot point to limit travel - means drilling a new hole in the lever arm. Nice car though. Lucky kid! Redneck solution would be to fix a block of wood behind the accelerator pedal.....
  15. kellys_eye

    Normal resistors for High Voltage application

    Note the resistance values..... 30MΩ and 50MΩ - quite typical for HV applications so as a 'normal' component user you'd be using a series of resistors to reach such values using 1MΩ, 2.2MΩ etc (or sometimes even smaller values like 470kΩ. At 250V per 1/4w resistor and using 10kV as the target...
  16. kellys_eye

    Where to find data about LED 155BRP made by AND?

    Chuck a resistor at it and measure it...... what's the worst you can do?
  17. kellys_eye

    Normal resistors for High Voltage application

    That's a project I'd be interested to follow Hop. Keeping it as 'math-free' as possible prevents attention-loss and I commend your approach in that sense - I find the 'practical' approach to be most useful and easiest to absorb. I'm going to give that project some time and attention and offer...
  18. kellys_eye

    12-0-12v, 230v, 1000watt inverter

    83A is the right figure..... generally, when going to higher inverter wattage, you go to higher primary voltages too - in this case going to 24V would half the primary current. If you look at ordinary UPS devices you will find they use 24/48V depending on their wattage. Using an old UPS for...
  19. kellys_eye

    Cooling soldering iron quickly after use to reduce oxidation

    The iron I use is a generic temperature controlled Hakko rip-off....... it heats from cold in under 10 seconds, stays hot if you move it (movement sensor) and goes to standby if unused for more than 30 seconds and switches off if unused for longer. $30 IIRC...... (you have to provide your own...
  20. kellys_eye

    Schematic Needed

    Sounds like your typical 'rebadged' type of thing.
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