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  1. HellasTechn

    What circuit makes a HIGH by detecting LAST pulse

    It is called "Missing Pulse Detector" and it is with a 555 timer. only with +5v VCC you are very close to the minimum 4.5V that the 555 can run with. I suggest a +6V or +12V VCC.
  2. HellasTechn

    No power

    It is so annoying when someone can not spend one more minute to explain what exactly is the device he is asking about or what the actual problem is but instead they expect you to already know the answer of their question to be posted.
  3. HellasTechn

    Help on resistor.

    The way i see it they are probably attenuating resistors. I doubt that you will damage the m.b. if you dont use them but you could start experimenting with 47k and 10k resistors like suggested by sir edd post#3.
  4. HellasTechn

    RC car not going backwards

    You could try lubricating the motor and gears to see if it helps a bit.
  5. HellasTechn

    Help on resistor.

    like you mentioned in post #2 he has to add the missing header and ribbon cable before he can connect the newly placed audio socket to the motherboard. maybe this front panel pcb was ment to be sold on pc's that didnt have audio capability or they just wanted to sell a different version...
  6. HellasTechn

    Make your PC Power supply last- 73's de Edd

    some of them in parallel to each other to increase capacitance. The higher the current rating for the rail, the higher capacitance needed.
  7. HellasTechn

    3-pin PC case fan -- power from alternative source?

    Tipically a black wire is the ground and a red wire is the +12v for the fan then a yellow or blue is the feedback to the motherboard. if that doesnt work then most probably its what Kellys_eye suggested. One other thing is that you dont really need a wall wart. Your PC PSU will supply +12V on...
  8. HellasTechn

    Help on resistor.

    Are you sure that the firmware of the audio chip (assuming the pc has one) can support line out and mic in ?
  9. HellasTechn

    555 pwm controller.

    Well i am not going to fix the device after all because like i mentioned he bought a used really cheap. I will probably build the 555 PWM circuit just to play with it anyway ! THANK YOU ALL !
  10. HellasTechn

    555 pwm controller.

    UTC 3563
  11. HellasTechn

    555 pwm controller.

    :) I have not forgotten about that. I will take a look tomorrow at work and let you know on friday.
  12. HellasTechn

    Clarification of terms S:N

    I beleave i am the "Master Chef" here !
  13. HellasTechn

    1996 Fender deville deluxe 212

    Hello and welcome to our forum ! A more detailed explanation will be essential before we can issue assistance since we dont know exactly what you have or what you have done to it. For example: brand, model, schematic if possible (or link to it), photos of the board if possible. That way our...
  14. HellasTechn

    555 pwm controller.

    I can not find it anywhere ! The thing is that the person who asked me to fix it, does not want me anymore to do it because he found a used one for like 15$. I am going to build the circuit anyway because pwm controllers are new to me and i want to play around a little bit. THANK YOU ALL FOR...
  15. HellasTechn

    555 pwm controller.

    Yes it is the original transformet. the one that came with the device. Exactly.
  16. HellasTechn

    555 pwm controller.

    Ho i am sorry. i didnt really pay too much attention on the title. I dont remember it right now but tomorrow i will let you know since i am away and dont have it with me. This circuit you linked should be fine with the about 22V that DC from the bridge-capacitor right ? I know that the 555...
  17. HellasTechn

    555 pwm controller.

    The original power supply was 1A so that makes me think that it will not draw more than that. (note that the motor is also rated 18Vdc) What i do not know is what impact will the new circuit have on current being drawn by the motor. So if i understand correctly your advice is to use an actual...
  18. HellasTechn

    555 pwm controller.

    i was thinking to build the circuit pictured below. not really. Anyway the transformer is indeed rated 1A. Yes i already have a few. To put it simple i need to control the speed of a motor that works with 18Vdc using a potentiometer. The current consumption will vary depending on the motor...
  19. HellasTechn

    555 pwm controller.

    Hello friends. A colleague gave me a nail drill that was damaged (rpm stuck to max). I found the controller chip shorted and can not find a replacement anywhere (local stores-ebay-aliexpress). It uses an 1Amp transformer to bring 220V down to 18 and a bridge-capacitor circuit to make it DC. I...
  20. HellasTechn

    The low quality busted headset sounds underwater effect

    That is true since we can only offer assistance via the internet and not in person.
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