The red lightcomes on when i hook up things to it
Usually, this indicates an overload condition. I have a Pyramid 35 amp supply that has no green light but uit does have a red light and an irritating little beeper that the instruction book says is activiated when power draw approaches 90% of rated output. (Why not call it a 30 amp supply if you can't use the full 35???) Enough editorializing. You don't say if the supply actually works, just that the light changes color. If it doesn't work at all, I would start with checking the diode bridge for a blown or leaking diode. If one is bad, it can output enough to drive an LED but fail anything else. If these are good, check the filter capacitor. If this is bad, the hum could concievably confuse the regulator circuit. Next, I would check what ever voltage regulator it has in it. I can't comment on specifics as there are many schemes that can be used. My unit, for example, is like a mouse driving an elephant. It has a small 723 regulator IC, (Aprox. 100ma output), controling 4 large TO-3 pass transistors driven by a 36 volt 40 amp transformer to boil it all down to an adjustable 12 to 15 volts.
The bottom line is without knowing if the unit is puting out or not and not having it in my hand to look at, this is the best I can do. I hope it helps.
Pyramid 10 Amp...
on Feb 07, 2011