You can convert a DOA to a GT24hr, but there are some notes:

1) You will need a filterboard that has the analogue inputs wired up (the DOA filterboard is just for digital inputs)

2) You can't play on your VR cabinet, totally different wiring, how the pot pedals and wheel can be made to work, you'd need to re-wire though.

3) No Model 2B CRX don't use external sound boards, only Model 1,2 and 2A CRX use the sound boards and for 2A CRX it is only the case for the Deluxe versions of Sega Rally and Manx TT where they use these for extra SFX.

4) Yes the optical fibre link cables are the same, like I said the filter board you have for DOA will not have the firbe connection points.

If you would consider selling it, you may reach me on

web@videotronicsuk.com

Thanks

Andy