Mamba max pro & savox servo cutting out
 

Got a brand new mamba max pro and savox servo and they cut out on me so I added a spectrum voltage protector to the reciever but its stll cutting out. Turned the mamba max pro BEC voltage upto 6v but still cutting out. What should i do to stop it cutting out? Do i need an external BEC?

You've got it right. The bec on the castle is rubbish. You can either use an external bec as you mentioned, get a less power hungry servo, or get rid of the mmp and buy a new esc with a proper internal bec. The funny thing is that castle make the best external bec's.

Ok thanks for the advice. Will go and get an external bec and wire it in. Hope that solves the problem

Before spending more money, try dropping the BEC voltage to 5.5V. I found this made it much more stable.