Did you not read this post?
http://www.soliforum.com/post/135330/#p135330
Also are you sure your printer is the big 1.0? That looks like the PCB from one of the mini's or JR. On the 1.0 the heater was not even connected to the board. There was a harness that came from the main board and ended at a connector just above the extruder where the heater would plug in. This connector was often defective and the source of many issue.
The easiest test you can do is use a blow dryer or hot air gun and heat the hot end with the power on. The temp on the hot end reading should rise. If it does not then again it is an issue with the thermistor, not the heater. The system expects the heater to heat the hot end several degrees in x time. If it does not see this change it cuts power to the heater. The thermistor is responsible for getting and showing this change in temp.
All you did in your test was connected the ground side of your hot end to an unswitched ground. On these printers all parts like the heaters have power at them when the unit is on. They then use logic to switch the ground on to allow current to flow and allow the unit to heat. So your issue again as said above is that logic is not turning on your heater as it cannot verify temp.
Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.