White screen after upgrade to v. 3.9.2

I have two wordpress installations in one sql-database.
They use their own table prefix. One is wp_ and the other one is intranett_

One of the sites was upgraded to wordpress version 3.9.2 a few days ago. The other one has not beed upgraded, because I don’t have auto-upgrade active on it.

The site that was upgraded now only shows a white screen: https://www.arkivsenteret.no/intranett

The other one that didnt upgrade is fine:
https://www.arkivsenteret.no

Both sites are built with the theme Pagelines Framework v. 2.4.5.

I have tried to rename and even delete all the plugins and themes, by using a ftp client, on the broken site, but it did not fix the problem.

Any suggestions what to do next?