Hi there,the green wires coming out of your trans. are the heater winding for all your tubes,that's why the amp shut down,no heater voltage.Depending on the amp,there could be a few amps of current running through them,(green wires).The byproduct of a bad connection is heat,and sometimes this will melt wires.I've seen lots of burned up trans. and htr. lines,there are a few things you can do to protect them,some people fuse the htr. center tap wire,(the green one with the yellow stripe),or you can disconnect it and add a 100 ohm 1/4 watt resistor from each of the htr.lines to ground,this way if your htr.'s short to ground,the resistors act like fuse links and blow saving the htr. winding on the trans.Hope this is of some help,Mel.