I posted this in a similar thread over on the IdeaScale website:
Not to be a downer, but you might want to Google "surface mount technology". The Sharc processor in the HD 500 is a 208 pin LQFP surface mount chip. These are almost impossible to replace by hand. To mount them, during manufacture, a solder paste is printed to the circuit board pads, then the chip (and everything else) is glued to the board. The whole thing is then run through an oven (or hot gas convection, etc). Everything is soldered on at once. It is great for fast, highly automated robotic production. It sucks for changing out a component. Note that this particular chip has 208 leads all .5mm apart (see here: http://www.analog.co...W)/SW_208_1.pdf). Even with a brand new chip and new main board very very few people could solder this by hand. Just look at all the YouTube videos of guys that wrecked their iPhone trying to change out the battery (with 4 leads a couple of millimeters apart).
It's not impossible to do by hand - but I don't think you could find someone to do it for less money than the whole HD 500X costs. Generally, with surface mount chips, you only get one chance to solder something on. If you have to remove the old chip it is very likely to destroy the pads on the main board. I think that is why the main board is replaced for most problems with a POD. In my experience, the repair centers won't even try to replace a component. Try finding someone to replace a soldered on CPU in a modern laptop. Same problem. I hope I'm wrong, though, and Line 6 figures out a way to do it...
This thread has migrated a bit - but thought it might be useful to add to this discussion.