Man, hate to burst your bubble but 1/8 inch is pretty coarse for burgers. That plate gives you a loose, crumbly grind that falls apart on the grill unless you really work the patties. Most shops I know running fresh grind for burgers go with a 3/16 or even 1/4 inch plate for better bind and juiciness, then maybe a second pass on 1/8 if they want it finer. For fat ratio, 80/20 is fine but a lot of folks bump it to 75/25 with fresh chuck since the fat renders off different than the pre-ground stuff.

Did you check the breaker on the iron or just chunk it? I read a forum thread a while back where a guy swore his iron died mid job and it turned out the cord had a bad spot right at the strain relief, so it would cut out when the cord bent a certain way. He opened it up and found the wire barely hanging on by a couple strands. Worth cracking yours open before you toss it, sometimes it is a ten dollar fix instead of a new iron. As for spares, I heard a lot of guys run two irons on the truck because the cheap backups have a habit of dying at the worst time. That top setter and damp towel trick is old school but it works in a pinch, good save on the seam.