silver-faced concert lead problem

[high on fire]

i just bought a silver faced concert lead off of a friend of mine for $50,but it has a problem..it wants to kick the circut breaker everytime it powers up.i had someone take a look at it and they found that a small black four legged table lookin thing was cracked or busted beside those two silver kegs laying on thier side(on the circut board)..sorry i dont know anything about electronics and the correct terms for these parts..its seems reasonable to me it does look like it went bad..he said everything else was fine transformer,rectifier,etc.,etc..so can anyone tell me where i could get this part and what the thing is called? its got four little legs and a black top, its pretty small.or is it even fixable? or could it be something else? and finally how does the silver faced concert differ from the black faced concert? the black faced has a couple xtra switches i see plus a tone knob for the reverb, but does it differ in sound?  thanks for your time..hof

[JoeArthur]

From your description, it sounds to me like one of the bridge rectifiers.  Some will have two squiggly lines on two of the wires, which should connect to two of the transformer windings.  The other two leads should have plus and minus signs.  Any replacement with equal or greater PIV and current ratings can substitute.

What you are calling the "blackface" concert, simply combines both of the channels of the "silverface" model into one, tossing in a reverb tone control and some front panel switches for the distort and boost functions in addition to having them be footswitchable.

[high on fire]

hey joe, the part im talkin bout doesnt have any wires connected to it..its just connected to the circut board..its small and round with four legs connected to the board..maybe this description helps a little bit..i appreciate the help..thanks, jude 0))

[JoeArthur]

You call them legs... I'll call them wires  

The concert has 3 separate secondary voltage supplies.  The bridge rectifier bolted to the bottom of the chassis supplies the output stage.  The other two supplies... supply the rest of the circuitry including the preamps, and the bridge rectifiers for these two supplies are located on the circuit board (I believe the power amp board, but I really can't remember).

From the power transformer, follow the two green (one is green with some other color stripe), the yellow and the brown wires to the circuit board.  The rectifiers are somewhere close to the pins that these wires connect to... and it would be close to the silver kegs (capacitors).

If the wires are on the bottom, then it is mounted outside down.  The markings I mentioned would be on the other side by the wires.  

Be careful when you unsolder it from the board - make some sort of mark by one of the leg points so that you know which leg went in which hole... this is important.

[high on fire]

joe, thanks for helping..where could i pick up one of these parts?  thanks again..hof