Heat in class A equipment

Heat is one of the biggest enemies of electronic equipment. Does anyone know if this Heat is only at the output transistors and their heatsinks o8is it also present in other components within the unit. 


I was planning to remove the top cover and with a IR thermometer going to check temps..


Has anyone done this? 


What do you want to do that for ? All class A equipment produces heat and it permeates through the whole lot. Don't take the cover off unless you know what you are doing and just let plenty of air go round it and it will be ok.