How do i unlock my Matsui tvr 180??

I have a Matsui tvr 180 that belongs to my friend as i am staying with her until i find a flat and recently my younger sister turned it off at the plug and when i turned it on again it asked for a code so i entered an obvious code and i was incorrect so i entered another obvious code in incorrectly and it lock so then i asked her what the code was when she got home and she told me what it was! Now i need to un lock the t.v again for her or i wil have to buy her a new one! how do i u unlock it?