Magento 2 Checkout page is completely build in Knockout Js. If you are getting blank page on checkout page on page refresh, please check the following points :
Browser console for any error. You might get any error in console.(
This kind of issues comes when you have either overridden any knockout js file and have some syntax error or undefined binding in knockout template file).
Network for failed request, you can check in response for failed request.
As per your comment, It seems that you have added any custom module with custom functionality calling totals. Do remove var/generation files or check your injection in the custom file.
If you will provide brief about your custom changes, It will be more helpful to provide proper solution.