occasionally that can be caused by oxidation on the sensor connector strip due to being in a damp atmosphere or being put in the case after use in damp conditions
You have to strip the camera to clean it though so its obviously best to replace the sensor whilst in there .
There were numerous threads around the internet how 100's of owners recovered use of their cameras by giving it a sharp jar which temporaily improved the connection
If I were you i would have bought a used S5600 off
ebay for £50-£60 much better camera and cheaper than a new sensor.
I've just sold a S5600 for £65 and 2x S5000 for £45.00 each on YACC forum.
One of them went to our very own Noodley