Thunderfire cannon techmarines

[Anakzar]

Can they take servitors?

I was playing today and my opponent had a thunderfire cannon with 3 servitors to act as ablative wounds. As far as I knew this was legal (I don't own the marine codex). But a person that stopped to watch for a bit told us that it was not legal...

It did take me an extra round to take out the Thunderfire cannon so I would like to know if its legal.

[SON OF ROMULOUS]

No its not legal. the tech marine is included in the purchase of the gun itself he isnt bought as if he were an individual tech marine. he cannot add any servitors or any type of gear to him.