Employment At A Company Which Repairs Equipment Used To Manufacture Haraam Items

In the enquired case (wherein a person wants to start a job in a company that is repairing measuring devices that are used by some companies which produce Haraam items), it will be permissible to repair such devices and machines without any abomination, since there is no direct assistance and abetting in sin and there is no direct connection between repairing such devices and producing the Haram items. 

In other words, repairing these devices is not unlawful in Shariah, especially since the company that you will be working for does not produce any Haraam items. The company merely repairs these measuring device for other companies. If those companies then use these machines to produce Haraam items, they are responsible for using the machines in the wrong avenues. After all, the same measuring devices could be used for producing Halaal items as well. You are not responsible for their actions. Similarly, if these measuring devices are used for power stations and if someone uses them for unlawful purposes, he will be accountable for his actions, not the person who fixed or repaired the machine.