Fried Terminal Block Connector - Elec Short

Not sure on the connectors, but they will probably be fine...

However, have you considered powering the heated with a separate power supply and relay?  You could be pushing the limits of your board by running it as is.

The same thing happened to me with my Sanguinololu, also from turning the printer around too much.  I took the opportunity to upgrade to an Azteeg, but when I fried the Azteeg, I replaced the melted connector and got the Sanguino running while waiting for the replacement.

Do not use a relay. Use a MOSFET or an SSR (it is designed to operate at the frequencies required for PID (<1ms vs >10ms). A Relay is open to welding either open or closed, and making and breaking mechanically high amp DC loads will kill it right quick. It suffers 'contact bounce' which produces a *ton* of electrical noise - which can show up as all sorts of missed steps and fun things to troubleshoot. 

There is a reason you do not see 3D printers shipping with relays - they have enough electrical noise issue what with ATX supplies, dodgy USB cables, exposed electronics with no shielding etc etc. And they are so prone to failure in this sort of environment (high temp, high amp).

All of this also sets aside the horrible racket the ticking relay will cause in PID mode holding setpoint.

I mention this because I've noted you repeatedly suggest the use of a relay - which is entirely inappropriate for anything but the most basic of Bang-Bang bed control - which is then prone to delamination and warpage issue due to the temperature deltas between heat cycles. Please consider this before suggesting it to others as a wise decision.

Fair enough - I'm being specific about it because its not just a matter of semantics - they are entirely different physical entities that behave markedly differently designed for different application requirements.