tech advise needed

I have an older threshold fet one pre amp
the other day it let out a "zittt "sound and shut off
the fuse didnt blow the on light is out and I have no sound

I opened it up and found a npn transistor shorted
my question is this something thats common? nothing else seems to be bad / just this transistor .I took them both out (there are 2 in the power supply and ordered new ones .should i dare just replace them and turn this thing back on ?

or get a new preamp ?
I would give it a try. Not much to lose at this point.
It's something that's common and power supply is usually primary target to diagnose.
go ahead and replace them they will probably just blow again anyway