Pyramid ps-15kx i had this power supply hooked up to a car amp in my house. after a while of bumping 2 12 inch subs the power supplys voltage went from 13.8 volts to 22.5 volts. i disconnected it from the car amp and it still puts out 22.5 volts. what happened and how can i fix it? it's gotta be something easy enough for me to do instead of taking it in and paying big bucks.

Unplug the PS-15KX 120V AC cord !! Then take cover off. DO NOT plug the AC cord in unless you are used to working around a lethal voltage and current !!!!!!!!!!

If you can use a Multimeter, then measure resistance across each pair of the 3 leads of the output transistors. You will probably find fractions of an ohm across a pair of leads. One or both may be shorted. NOTE: Do not ever measure resistance in a powered up circuit, kiss meter bye-bye and maybe burn you too.

By putting more robust transistors in this supply, you may not gain much reliability. The supply is rated at a continuous current draw, which is less than the intermittent current they advertise. Read the spec's of any power supply you get and look for continuous current ability.

There are several better transistors that will substitute for the 2N3055. You will need to look at a transistor substitution book and check specs. The internet is great for this. I used to use all kinds of data books, and still have them! But looking up info on-line is nice. Motorola has some that will fit and have higher current and voltage ratings,

Get someone who is a ham or geek if you aren't sure about sticking your fingers in the power supply.

Be Careful, Work Safe, it is a factor of longer life.

Probably have a shorted Pass transistor. That supply may even have the 2N3055 transistors in it.

If you are handy with soldering iron and multimeter it won't be hard to fix.

Schematic is availible At this url.

http://www.pyramidcaraudio.com/manuals/PS15KX.pdf

Have a Blessed Day
BJ