Hello everyone this is my first post here and I heard this is the place to get the most knowledgable advice on all things electronics so here I go.
I have had a pyramid power supply model no. PS-26KX for over 2 years now and its primary use was to bench test 12V car audio and electronics. All of a sudden as I am testing an amplifier speaker combo the power supply shuts off and blows the 6amp 250v fuse. I replace the fuse and when I switch on again walla! blows the fuse again. where should I start troubleshooting?

 

Here's a similliar thread, same supply http://forum.allaboutcircuits.com/showthread.php?p=147335

 

Start by disconnecting the amplifier. Then try a new fuse. If that doesn't work, try to get a schematic of the power supply so we can see how it's made.