I agree that the words
already and
before make the order of events clear.
However, there is a difference if 'had been broken' is used
instead of 'were broken'. In the phrase 'were already
broken', the word '
broken' is clearly an adjective and '
were' is the simple past tense,
active voice of the verb 'be'. There is no suggestion that the machines were broken
by someone. It simply says the machines were already in a broken state.
If you change '
were already broken' to '
had already been broken', I'd understand the past perfect
passive of the verb '
break' and therefore there would have also been an agent that/who did the breaking (
...had been broken by someone). And that would be a change in meaning.
In my opinion, if you want to use the past perfect in the sentence and
also want to avoid changes in meaning or misunderstanding, then it would be safer to say '
had already broken' (active past perfect of 'break').
Leaving the sentence the way it is is fine.
As to your second question, I'd recommend using 'the'.