Hi! I was happy to stumble upon this forum and plan on learning some of the basics from the links provided... as my house is full of musicians often times, the instrument area  has a special section we call the amp graveyard.  I placed my gallien kruger 250 ml there a while back but then I kinda got an interest in fixing it cuz it seemed simple in a way....

anyhow. the amp turns on and has the standard minimal running hiss sound coming out of the the 2 tiny 6 inch speakers.  same goes for it if it is plugged into a cabinet.  I plug in a cord to the input and tap on it and it yields no results. 

This made me think that it could be the input jack.  I checked it out and one the contact metal parts no longer seemed to be touching the cable Male part... (?? does that make sense??) anyway, I thought I should replace it.  And I did since it seemed easy enough because it was connected to the board via three wires not being integrated like on fender amps I've opened up.  so I did that and there are still no results-- but now sometimes when I insert the cable there will be a quick crackle sound that comes out of the speakers. 
I brushed some wire over the (this seems funny now that I type it) pin side where the wires from the input jack are on the board and sometimes I get the same result.  So far I can't think of any conclusions really from this. like I said I'm new to this amp shindig... the only thing I can think of is maybe replacing the wires that come off the board?

Ok that said... one more thing. something I just noticed.  way down by the effects send return loop there are 2 resistors that are burned. they are very close to the input output jacks of this part of the amp. could this be the obvious problem or not?
maybe I should post a pic?
well, any input would totally be appreciated!!!
glad I found this forum!