I have just upgraded my Mastech HY1803D lab power supply with a 10-turn voltage adjustment potentiometer. In order to perform the upgrade, you would need a 6.8K potentiometer (at least the original is). The trickiest part is removing the knob from the old pot. It is glued on, use pliers, soft padding and some leverage to pull it off. It would be best to do it before taking the PSU apart – the cover holds the front panel.
Test results: 1) voltage adjustment is easy and accurate. 2) the slow voltage climbing I had experienced during longer runs is gone (did not expect that but MISSION ACCOMPLISHED)