From Priyanka's comments above, I would contact Oppo to get a quote for the cost of a replacement motherbaard if you are out of warranty. Their [http://www.oppo.com/en/supports/|support] page should provide you with the relevant contact information to get in touch with them. I reviewed the [guide|32843|OPPO N1 Motherboard Replacement] to see what the motherboard looks like and found one listing on [http://www.ebay.com/itm/OEM-UNLOCKED-OPPO-N1-REPLACEMENT-16GB-LOGIC-BOARD-MOTHERBOARD-/141946852223?hash=item210cb1137f:g:AVUAAOSwGYVW~uas|eBay]. As, I am in the US, my search may not expand to sellers in the EU, so you might want to try a similar search if you are not in the US.
I would recommend contacting the iFixit [https://eustore.ifixit.com/|EU Parts Store] support to also see if they have any recommendations that might be helpful as well.