Corollary to Murphy's law

The resurrection of the tuning list suggests the following corollary
to Murphy's law:

When something has gone wrong but is able to fix itself, it will not
do so until you have given up trying to fix it and bought the replacement.

By the way, we're not sure if Murphy's law is universal, but we know
it works on the planet Venus. After 10 attempts by the Russian Venera
probes to survive incredible temperatures and pressures and sulphuric
acid atmospheres to land and take measurements of the hardness of the
surface of Venus and send back images. The first such image showed the
penetrometer carefully measuring the hardness of the camera's lenscap!

Just to correct a couple of details. The lens cap thing actually
happened with Venera 14, after 12 unsucessful and one successful
attempt. The penetrometer and camera both worked for the first time on
Venera 13. So much for 13 being an unlucky number.
http://www.abc.net.au/science/k2/moments/gmis9907.htm