Default need help with otg strange problem

Hello guys'

I have a grouper 16gb nexus 7 which is acting really weird. It only works with certain data cables, no obvious difference between them. Both charge and data work or don't work with different cables. I can only think that the otg cable adapters would follow the same pattern but I have tried about 6 adapters so far none work' including a sandisk USB stick with otg adapter included. I have tried about 5 different ROMs' still no luck, I'm beginning to think I should sell the tablet and move on. Any advice?

Thanks.