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  1. TheChad

    Koford (Slot Car) Bench Power Supply Project

    The power supply is small, I'm guessing they used that type of Transformer because it's smaller that a 10v 10a transformer..
  2. TheChad

    Koford (Slot Car) Bench Power Supply Project

    No numbers or marking on it anywhere. It's blown. I am trying to replace it for a friend. I believe it's 8-10a 10v, so maybe 2x 5A 10v? I have not been able to find anything like it yet. Does it have a trade name? Thanks, -TheChad
  3. TheChad

    Koford (Slot Car) Bench Power Supply Project

    VA1, VA2, VB1, VB2
  4. TheChad

    Koford (Slot Car) Bench Power Supply Project

    Any idea what kind of transformer this is? 4 outputs? Thanks, -TheChad
  5. TheChad

    Koford (Slot Car) Bench Power Supply Project

    Here's the pic of the Auto Transformer..
  6. TheChad

    Koford (Slot Car) Bench Power Supply Project

    Gryd3, Check out this picture... http://variac.com/staco_variable_transformer_1000_1200.htm Variable Auto Transformer?
  7. TheChad

    Koford (Slot Car) Bench Power Supply Project

    No, the internal pot moves in .01v increments, but it's a "infinity adjustable" pot, it doesn't have a start or stop. If I turn the set screw quickly on the internal pot, it will jump a little, but that's to be expected.. -TheChad
  8. TheChad

    Koford (Slot Car) Bench Power Supply Project

    Maybe a little, but not really... I lowered the voltage all the way down to 4v and the precision of the external pot is still not there... I think that's the problem really, the pot is just not precise enough for small incremental adjustments... -TheChad
  9. TheChad

    Koford (Slot Car) Bench Power Supply Project

    Okay, I did try lowering the voltage on the internal pot down to 8v, but it still seemed to jump around too much when dialing the voltage in... I will try going even lower to fine the sweet spot! Thanks, -TheChad
  10. TheChad

    Koford (Slot Car) Bench Power Supply Project

    I've used pots that "click". Which would make control much easier... But I don't know if they make them with built in switches and they were of the "infinitely adjustable" type.. Maybe I should try a different knob! My knob is a 1.25" knob.. I found that one pot I posted above...
  11. TheChad

    Koford (Slot Car) Bench Power Supply Project

    Okay, today I measured the internal pot and external pot... (Disconnected from each other) The external all the way up measures ~44k Ohm, the internal pot all the way up measures ~43k Ohm All the way down they both measure "0".. With the internal pot set @ ~17k Ohms, the voltage is @ 12.6v...
  12. TheChad

    Koford (Slot Car) Bench Power Supply Project

    I am thinking maybe changing out the current POT which is a 260-Degree 20% tollerance Pot, to this one: http://www.digikey.com/product-detail/en/450T328F503A1C1/CT3058-ND/4733108 which is a 320-Degree 10% tolerance pot. This should give me an additional 60-degree's of adjustment and being of a...
  13. TheChad

    Koford (Slot Car) Bench Power Supply Project

    What's the point of having a small value pot at all? Why not just put in a 10k ohm resister in series of the 470 OHM pot? By using 2 pots in series like that, you would also not be able to turn the voltage down to minimum voltage with out turning both pots down to "0" right? -TheChad
  14. TheChad

    Koford (Slot Car) Bench Power Supply Project

    Well, at this point it doesn't seam like I have any other option, unless I want to go to a multi rotation rheostat, which I don't think would be very good for my application... I really don't need 12v, I set it to 12.6v just because the transformer said 12.6v so I figured for consistency I...
  15. TheChad

    Koford (Slot Car) Bench Power Supply Project

    If I were to remove the internal Rheostat from the picture and tested the external rheostat to be at the appropriate Max voltage of 12.6v at say 30k Ohms, would getting a 30kohm rheostat not give better control/adjustability because the additional 20k ohms of range is simply removed from the...
  16. TheChad

    Koford (Slot Car) Bench Power Supply Project

    Well, the current external Rheostat's range is from 1'o Clock to 9'o Clock.. I don't have any room to add a 2nd external rheostat.. So the External rheostat is 50k... But if the internal rheostat is turned down to say 20k, then I would only need the external rheostat to be 20k right...
  17. TheChad

    Koford (Slot Car) Bench Power Supply Project

    You are correct, the 2 rheostats are wired in parallel to achieve a final result. I took the external rheostat and turned it all the way up, then turned the internal rheostat down to achieve a final MAX voltage of 12.6v, with out the 2 wired in parallel, the max voltage is ~14 something volts...
  18. TheChad

    Koford (Slot Car) Bench Power Supply Project

    Hey guys! Well been using the new power supply for a few months! It's been working fantastic! No heat regardless of amp/voltage! My only problem at this point is that it's very hard to adjust voltages minute amounts, a tiny bump of the knob jumps the voltage... Today I took a measurement...
  19. TheChad

    Koford (Slot Car) Bench Power Supply Project

    ... and of course the ORIGIONAL Power Supply!
  20. TheChad

    Koford (Slot Car) Bench Power Supply Project

    TA-DA! It's DONE! Took awhile to get there, but this project is complete! Thank you all soo much for your help! I definitely couldn't have done all this with out you guys!
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