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  1. duke37

    Casio Privia Px330 Piano Keyboard power adapter input

    It looks like a standard coaxial connector, possibly 3.5mm diameter. There are several variations with different pin diameters. Get a plug and matching socket and connect with the pin positive. You could test the keyboard using a 12V DC supply connected with some soldered wire on the board...
  2. duke37

    Simple DC Motor setup - NEWBIE HELP!!!

    You probably do not need to rotate continuously, one minute in each hour should be enough. The germinating floors in the UK used to be stirred with a man with a shovel. I do not need any nazal spray.
  3. duke37

    Telicine machine schematic

    T = Time delay, I.E. antisurge, used to allow some overcurrent during switch on when large capacitors need to be charged.
  4. duke37

    Simple DC Motor setup - NEWBIE HELP!!!

    You will need a gearbox to reduce the motor speed and increase the torque. I would try a 12V DC windscreen wiper motor. This could be powered with an old style 12V battery charger. This will give the required isolation.The speed could be pre-set electronically or by using one or more series...
  5. duke37

    Power supply for 1960s movie projector

    Find a handbook which details Voltage,Current and Frequency. The plug can be replaced but might be the least of your problems. If the voltage is different to what you are supplied with, then leave the plug in place to avoid the wrong voltage being applied. I have made an isolating transformer to...
  6. duke37

    Reverse bench grinder

    Ball bearings come in a range of clearances, A large clearance is necessary to take an axial load.The balls then run up the side of the groove to take the load. A bearing with little clearance will not allow the balls to run up the side of the grooves so the forces will be very high due to the...
  7. duke37

    capacitor testing for novice please

    You will need a 250V DC power supply (old radio?) and measure the voltage with the capacitor in series with the meter. You should get a reading of zero.
  8. duke37

    Reverse bench grinder

    A drill needs a bearing which will take a large axial load. Does the grinder have such bearings?
  9. duke37

    Switching between two batteries.

    I do not like relays because of reliability issues, however, in this case,a micro relay may be better than a semiconductor which needs considerable voltage across it or to turn it on (FET).
  10. duke37

    Simple power supply that can be embedded in a wall socket

    The 100k resistor should be 1W and 250V minimum.
  11. duke37

    Simple power supply that can be embedded in a wall socket

    The resistor and capacitor are in series, not in parallel Is the resistor 1k or 100k? What is its purpose?
  12. duke37

    Equivalent Circuits

    My fingers do not always go where they should.:)
  13. duke37

    Toshiba VCR Blown Fuse

    The fuze could be the common 20 * 5 mm size. If the fuze is blown, something else is likely to be faulty.
  14. duke37

    Equivalent Circuits

    V2 (48V) has 18Ω across it and supplies 3A. The ouput will be equivalent as long as the circuit does not overheat.
  15. duke37

    Just a quick check of my circuit

    There is no ground connection on the crystal proper. The ground(s) will go to the crystal can as shielding to give better stability.
  16. duke37

    Transistor LED Circuit

    Once the source of M1 rises above the threshold voltage of M2 then that will turn on which will turn on M3 and so on down the chain. The LEDs will not light as the FETs do not take gate current.
  17. duke37

    round slotted nut tool ?

    Try to find a piece of pipe which can fit over the screw thread and grind the sides to give the tongue to fit the nut. Pehaps modify a box spanner. I have some of the necessary drivers but they have been put away safe.:)
  18. duke37

    Need help keeping a rigid mechanism in a 60ºC(140ºF) Incubator

    You could screw up the bolts till they reach the yield point. Alternatively include a Belleville washer to maintain the force as the dimensions change. Use locking nuts to stop them spinning.
  19. duke37

    polarity protection with diode between vcc and gnd

    I have had a fooster and found the circuit I was after. The diode is within the FET.
  20. duke37

    polarity protection with diode between vcc and gnd

    Battery driven equipment can often run on lower than the nominal voltage. I would try a diode in series with the supply and see it it works satisfactorily. There is a cunning circuit using a FET which is only turned on with the right polarity. I have never tried this.
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