how to hack a 6.5 inch screen to work with pi

I'm guessing you've already watched Episode 168 where Ben uses a field programmable gate array (FPGA) to create the signals required by LCD screens?

Episode 169: Ben Heck's FPGA LCD Driver Hack Episode

A brief search seems to indicate that it is a Sharp unit if the Part No is LQ065T5GG63

There are eBay  LCD driver boards that have been used to varying degrees of success, some spectacular fails and some function exactly as hoped. One thing they do rely on is the LCD being driven by LVDS (Low voltage differential signaling), fortunately this is a fairly common standard, (and the one Ben replicates in the episode indicated).

https://en.m.wikipedia.org/wiki/Low-voltage_differential_signaling

If there is no other option for you than retaining that screen then you could do worse than contacting an eBay seller with your model number and see if they can provide you an LCD driver board.

Prices seem to range from £5 to £30 ish  -  price is no  guarantee of quality!!

Alternatively, the same brief search on eBay (UK) revealed a complete 6.5" LCD & driver package for between £45 and £65 GBP 

I'm guessing you've already watched Episode 168 where Ben uses a field programmable gate array (FPGA) to create the signals required by LCD screens?

Episode 169: Ben Heck's FPGA LCD Driver Hack Episode

A brief search seems to indicate that it is a Sharp unit if the Part No is LQ065T5GG63

There are eBay  LCD driver boards that have been used to varying degrees of success, some spectacular fails and some function exactly as hoped. One thing they do rely on is the LCD being driven by LVDS (Low voltage differential signaling), fortunately this is a fairly common standard, (and the one Ben replicates in the episode indicated).

https://en.m.wikipedia.org/wiki/Low-voltage_differential_signaling

If there is no other option for you than retaining that screen then you could do worse than contacting an eBay seller with your model number and see if they can provide you an LCD driver board.

Prices seem to range from £5 to £30 ish  -  price is no  guarantee of quality!!

Alternatively, the same brief search on eBay (UK) revealed a complete 6.5" LCD & driver package for between £45 and £65 GBP 

Thanks for the info. I have been searching online but sometimes I don't have a clue what I am looking for.

I have watched that episode of tbhs but he uses a 4 channel o-scope and that is not a tool that I have or plan on having any time soon.

I also don't have access to a scope either, Ben was basically programming the FPGA to convert the signals to the LVDS standard the LCD required, supposedly the LCD driver boards do that for you? (Thankfully)!

I cannot advise how good the boards are though - I know others have had issues but some they've been ok for.

Once I dig my spare Laptop screen out I'm gonna chance it for about £25, it's worth a punt to me because of the screen resolution I can get for that price.

Good luck with yours.