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  1. kellys_eye

    Yorkville 100watt Mixer/Amp - Replaced Transistors

    What is JA11 (or JA14 for that matter?) Connect your meter negative lead to ground (the ground at the main smoothing capacitors would be best) and then use the positive probe to measure TP1 and TP2. They should both read the same (albeit one will read positive, one negative) and at the...
  2. kellys_eye

    Yorkville 100watt Mixer/Amp - Replaced Transistors

    As an aside - double check the pinout for the BC550. These packages often have different lead outs from what's posted on the schematic.
  3. kellys_eye

    Yorkville 100watt Mixer/Amp - Replaced Transistors

    What about the voltage at the junction of the output transistors? Measure at TP1 and TP2. 'Hot' is a relative term but given you have the correct voltages on the 16V rail there is nothing to worry about.
  4. kellys_eye

    Bush DVD

    ISTR that only one port on a multi SCART device is capable of auto-play/detect. I also STR that the Sky Box is a known issue for auto-play throughput. Either way, disconnect the Sky box and attach it to the TV such that it 'did what it used to' (i.e. autoplay) then start from there. If this...
  5. kellys_eye

    Bush DVD

    How have you got them connected? Is the DVD player connected 'through' the Sky box, then the Sky Box to the TV? You may have swap the arrangement around (Sky Box to DVD then DVD to TV) or the TV might have two SCART sockets and you connect them to the TV individually but you might have to use...
  6. kellys_eye

    Problem with ORIEL Xenon Lamp power supply

    The FET is switched via the opto-isolator which itself is activated by K1 (relay) which is activated by........
  7. kellys_eye

    Migwelder wire feed control

    FET is ok? Then you're getting the same (but amplified) squarewave at the FET 'output' (i.e. the motor)? Is the squarewave duty cycle varying with the control?
  8. kellys_eye

    Voltage converter circuit

    You would normally control a motor WITH the PWM signal, not an analog voltage. Use the PWM signal to drive a MOSFET that is in the motor circuit power supply line. Set the supply to the motor to 10V (or whatever) Apply your PWM 0-5V to B3.
  9. kellys_eye

    Required IC TH2167.1/ equivalent

    Seems common enough on eBay - why not just order the right part? Even ordered from overseas it shouldn't take too long to receive???? It's a manufacturer specific ASIC so no datasheet (easily) available and certainly no direct replacement.
  10. kellys_eye

    Migwelder wire feed control

    Change the chip - probably an LM324?
  11. kellys_eye

    Could a water flow sensor sense gas flow?

    No. Density of the material being measured.
  12. kellys_eye

    Step down transformer reference list?

    No. The increase from 230V to 240V represents around 5% voltage difference so the 12V output will increase to 12V +5% which is 12.6V - not worth worrying about.
  13. kellys_eye

    Yorkville 100watt Mixer/Amp - Replaced Transistors

    At the power supply itself or at the output transistors. Next check would be to measure the DC voltage at the junction of the two emitter resistors - should be zero volts with no signal applied.
  14. kellys_eye

    Migwelder wire feed control

    Probably a simple PWM driver. Check the potentiometer isn't open circuit at one end of the track (including cracks in the pcb). Check the switching device (transistor or mosfet) isn't defective.
  15. kellys_eye

    Bush DVD

    Are we supposed to guess the make/model of the equipment you're using?
  16. kellys_eye

    Is it possible to fix old PC monitor

    There is a separate SMPS section (identified by the clearance areas of 'no copper' on the underside of the board) that needs to be checked and - if required - repaired first. I suggest that the OP skill level set is minimal and that, even f the fault could be identified, sourcing and replacing...
  17. kellys_eye

    Yorkville 100watt Mixer/Amp - Replaced Transistors

    Check the main supply voltages first. The +/- 38V to the amplifier and the +/- 16V to the pre-amp circuitry. Report your findings.
  18. kellys_eye

    Yorkville 100watt Mixer/Amp - Replaced Transistors

    That's not a schematic.
  19. kellys_eye

    Looking for help with some projects that require electrical expertise

    Have you calculated the maximum lift available from the props? How does this compare to the unladen weight of the vehicle with a gasoline engine and battery pack installed? You're looking at an 8.5kVA generator (12hp motor/generator at around 100kg unfuelled) just to generate the base load...
  20. kellys_eye

    Migwelder wire feed control

    Got any pics?
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