What is a markov model and how to use it in predicting failure modes of instruments?

Answer 1

Here is a short description from Wikipedia

http://en.wikipedia.org/wiki/Hidden_Markov_model

Your failure model will depend on the instrument

Ex. state 1 = Instrument is working 100%
state 2 = Instrument has failure A (say broken chord)
state 3 = Instrument has failure B (say out of tune)
etc
Then you specify all probabilities to go from one state to another (most may be zero)