Developer's Corner Master Index ->
K4 ->
Serial port ->
Also:
https://www.mobileread.com/forums/sho...7&postcount=27
Also:
In the index system, see if there is a "teardown" listed for the K4
Things such as:
http://blogkindle.com/2011/09/kindle...sembly-part-i/
Although a web-search tool might find ones with more detail (like gently heating the center of the back with a heat gun (hair dryer?) to make the glue release easier).
If you can avoid it, it would be better that you did not try to solder to the pads on the circuit board.
Even geekmaster (with more decades of experience than is polite to mention) had trouble with the pads lifting.