Promac Calibrator Model DHT 730

[Aladio]

I am the proud owner of a Promac Calibrator Model DHT 730.  I am wondering if anyone here has ever used a unit like this and if they have, is it worth fixing?

https://www.ebay.com/itm/Promac-Calibrator-Model-DHT-730-w-Case-amp-Accessories-UNTESTED-Promac-Controls-/312689805338?nma=true&si=lCTiOHBh3NOgbIhK8DUEtiQl7A4%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557

Unfortunately it is not working. Nothing on the screens, nothing on the inputs or outputs. I have done some rudimentary testing but so far have only be able to make the LCD show all characters for a split second when switching off.  I have not been able to find anything on the net about this model.  I do have an instruction manual for the DTH 720 and it is pretty close but not the same.

Thanks in advance to anyone who takes the time to respond to this post!