Accounting for machines in the labor theory of value I have read that the Labour Theory of Value holds that the value of a good or service is determined by the total amount of labour involved in its production. To account for this properly, we must count not only the labour directly involved in finishing a good, but also the labour needed to produce the tools used in that process. 

I am curious: how does the LTV suggest the labour involved in producing a machine should be divided across the goods that machine is used to make. In particular,


If the output of a machine is arbitrarily reduced, what happens to the value of the goods being produced? If we simply divide the labour put into the machine across the units produced then it seems like their value should increase, but then it seems like the whole notion of value becomes quite arbitrary.
Suppose I built a machine that, in any given hour, produces one unit of penicillin and one unit of randomly mixed chemicals (from the same raw materials). Does this mean that penicillin and mixed chemicals should have equal value?
"I have read that the Labour Theory of Value holds that the value of a good or service is determined by the total amount of labour involved in its production."
That would be Adam Smith's version of the LTV, which according to him only holds in pre-capitalist societies. 
Karl Marx's version is thus:
the value of a good or service is determined by the total amount of socially-necessary labor involved in its production.
Socially necessary labor is basically the average amount of labor a society (industry, trading network or whatever) requires to produce a good. 
It takes far less labor time on average to produce randomly mixed chemicals than to produce penicillin from chemical precursors.