Yamaha PSR S970 Not Loading After Key Replacement

Helo everyone, a pleasant evening to you guys.
A client of mine write me today for a professional advice and possibly solution. It says;

“Hello sir, it’s Yamaha Psr S970
It was working fine before, just one of the keys got broken and I opened to fix it. Closing it back it won’t boot.
Will it require changing the board?
Pls what do I do?
Thank you very much.”

That’s his message to me. Please what can he do?
I believe we have very good tech guys here so I decided to bring it to the house for Deliberations.

Thanks to you all for your quick response.

Check the ribbon cable connections. I worked on a P85 recently and the ribbon cables are very weak at the connector. The unit would not power up after key repair. New cables and all is well…Tony

Thanks for this information, but the Keyboard still powers up but didn’t load to menus.

Could what you said still applicable for not loading to menus?

Thanks for your quick replies.