what are the symptoms of a bad transistor?

I am posting this all over the place hoping some one can help...

My RG100ES has recently started sounding loose in the bass end and sort of blah.  I put new filter caps in it and the humming at idle did drop by a noticeable amount.  But it just doesn't sound as good as it once did.  Someone suggested the output transistors?

Any ideas what could cause the low end to start sounding flabby?

Thanks, gang.

Volume drops were happening to me on the RG100ES XP when the rocker switch was failing.  Randall replaced the treble pull knob with a rocker.  I stuck a new mini toggle in there and the problem went away. 

I have a newer issue.

My RG100ES has recently started sounding loose in the bass end and sort of blah.  I put new filter caps in it and the humming at idle did drop by a noticeable amount.  But it just doesn't sound as good as it once did.  Someone suggested the output transistors?

Any ideas what could cause the low end to start sounding flabby?

Thanks, gang.

Everytime I ever tried to use the effects send on my RG100ES, the target amp or power amp has always buzzed like a demon!  I do not understand how anyone can use it at all.  Contradicts every you've heard about Dime's setup, right?  Maybe I am missing something obvious? 

My RG100ES has recently started sounding loose in the bass end and sort of blah.  I put new filter caps in it and the humming at idle did drop by a noticeable amount.  But it just doesn't sound as good as it once did.  Someone suggested the output transistors? 

Any ideas what could cause the low end to start sounding flabby?

Thanks, gang.