Solid orange light and timeout trying to upload sketch to Mega 2560

Hi folks,
I'm very, very inexperienced when it comes to Arduinos, so I hope you will bear with me.

I have a 3D printer that runs on a RAMPS shield and a Mega 2560. Something on the shield seems to have been damaged and it has now rendered two Arduinos unusable.

I have a solid orange light at pin 13 and I get a timeout error trying to upload the blink sketch. From the bit of reading that I've done, it seems that I may have corrupted the bootloader.

I would love to salvage the megas if possible. Can anyone give me some pointers on how I might proceed? I'm willing to pick up a USB programmer, but I'm just not sure what I need. Most of the ones that I've seen indicate that they are unable to flash a bootloader on a 2560.

I've tried to upload the sketch on two Macs. One running 10.6.8 and another running 10.8 with the same results. The system profiler shows the Arduino, and the port appears in the menu of the IDE.

Thanks in advance.

-Chris

After doing a bunch more reading, it seems that it should not be too difficult to try to re-program by using another Mega 2560.

Are there any caveats here?

Thanks,
Chris

So, plodding ahead, I was able to re-flash the bootloader to the mega using a spare Uno and Nick Gammon's excellent instructions.

Now mega is running the blink sketch from the bootloader, but I am still getting to following error when I try to upload a sketch:

avrdude: stk500v2_ReceiveMessage(): timeout 2560

I also tried a loopback test, which failed.

Then, while inspecting the board, I noticed some burned looking areas around some of the pins on the back of the board. I've attached a photo. . .

Is it ready for the junk pile?