I looked in some of the manuals and couldn't find Tecumseh for a Vendo 39... I actually have very little information on Tecumseh Refrigeration Units...
Can you get a picture of the condensing unit (lower unit) and post it here?
Does your 39 have the round or square evaporator? Chances are a square one will indicate that the refrigeration unit has been replaced or that this is a later model 39...
At this point, I don't want to post a schematic for the wrong unit, so if I had a picture, looking at the unit I could get something that should work... hopefully.