Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: ashura on September 17, 2015, 07:13:36 PM
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Hi. I have had my crack with speedball up and running for a while. I upgraded to film caps and bypassed them with no problems. I also added the Cree diodes with no problems. Then I decided to repaint and rewire the whole thing with cloth covered wire. Now with every turn on I blow the 270 ohm 1 watt resistor in the power supply on the last cap. Help. Also, should I have 120v at terminal one or two on the transformer. It seems like it should be terminal two as it is labeled 120 on that terminal but I am getting 0 volts there and 120 at terminal 1 in the transformer. I verified that the wiring is correct.
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Hi. I have had my crack with speedball up and running for a while. I upgraded to film caps and bypassed them with no problems. I also added the Cree diodes with no problems. Then I decided to repaint and rewire the whole thing with cloth covered wire. Now with every turn on I blow the 270 ohm 1 watt resistor in the power supply on the last cap.
That resistor is not supposed to be 270 Ohms.
-PB
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Should be 270K ohms if I remember correctly.
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Thanks! I suppose such a large difference in resistance would cause that now wouldn't it! I had bought new resistors to replace the old ones instead of reusing them and got the wrong ones.
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Yes, 270 Ohms is a lot different than 270,000 Ohms. 270 Ohms across the power supply will draw just about 1 ampere of current. The Crack circuit draws about 0.080A of current.
That resistor will dissipate 270 watts, at least for the few tenths of a second that it can before it vaporizes.