Ddj sx2 keeps freezing

I recently had my DDj sx2 replaced due to led failure, now i am having problems with my replacement unit.

The problem is That everytime i start to DJ the unit works fine for about 10 mins to an Hour, then it just freezes i.e. The leds on the unit freeze, apart from the master output which still produces sound. And this happens everytime without fail.

Then i turn the unit off, close serato, and try to power the unit back up, but the unit doesnt turn on, so then i wait between 10-30 mins for it to start back up.

I have tried every fix possible for example;

I removed all corupt files

Removed itunes library completely and only used a limited amount of songs

Analysed all songs

Tried using brothers brand new laptop with 13gb ram on i7 processor

Im using a Macbook 2010 white model
With 2.53 ghz intel duo core
4gb ram
Running the latest version of serato