Hi it should be up to voltage at that try another 100 or 200mv,reflow the solder joints on the dcdc,you will probably fine another 100mv will do it,you could allways get a cheap new dcdc adjustable buck boost new from china £1-2,
anyway I got my display working, the only thing it does not show all of my ,LON W 0:56:00.451
what is good for us hams is it shows the locator
Dave 2E0DMB