Atari's AR power boards are horrible, mainly due to the linear power supply overpowering the poor pcb's causing those resistors to flame!
I've bulletproofed every single one of my Atari AR boards using this advice:
http://www.stickycarpet.com/pinx/ar2mods.htmlI've even removed that stupid useless R29 resistor and replaced it with a jumper wire, who thought of this +5vdc sense crap? argh!
And sometimes, I just don't wanna
with it and go with a switcher cuz it's cheap and dammit it's EZ-2-DO!