Wiring Embedded Display Port (eDP) to a full-size Display port
I removed the eDP ribbon connector and soldered a terminal block with
jumper wires to it.

DisplayPort data lanes must be carefully made of &quot;twinax&quot; wires, to form a flawless differential transmission line. The DP data protocol uses &quot;link training&quot; to establish clock and symbol &quot;lock&quot; before being able to transmit data packets. Jumper wires presents (generally) horrible signal reflections, and if a link cannot find equalization parameters that provide certain error rate threshold, the link won't transmit any visual data.
So you need to fix the signal integrity on DP data lane.
ADDITION. Upon close examination of &quot;quanta_zhk_r3a_20140630_schematics.pdf&quot;, the &quot;eDP&quot; port on this laptop appears to be a combination of 2-lane DP and 2-lane USB3 (to support touchscreen function). I don't believe that a standard 4-lane DP monitor can auto-detect and auto-negotiate the lane re-sizing, that's likely why this monitor shows nothing. This also could be a lack of firmware support on laptop side, since full DP was not an original option for this design.