repair a broken screen on a HP slate 7 plus?

A broken or cracked screen will usually require a replacement. The HP Service Manual does not list a part number specifically for the screen. It does lists the four models of the motherboard, based on their color variation.

Upon entering each part number in the HP Part Surfer, the models listed are the:

HP SLATE 7 2800

HP SLATE 7 2801

HP SLATE 7 4600

HP SLATE 7 4601

Upon doing a search based on the models listed on eBay, there are parts listed with the digitizer and LCD individually or as a combination.

Also note that you may be also able to order parts from an HP Authorized Parts Partner.

Upon reviewing the Product End of Life Instructions, this document provides photographs of how components are further separated beyond the system board that detail how the display is separated.