I worked many years with L3-3, I still have a working one but I use it only to test rectifier tubes, it uses real conditions for rectifier test - better test than simulated low DC test. For other tubes I built a Roetest, compared many features and faster test.
Some time ago, before Roetest, I bought 2 testers L3-3 "as is", lottery but the price was acceptable, checking them one looks perfect like new but missing main transformer and wire wound resistor attached on transformer, the second one looks used, some oxide inside, at first look I noticed that the ceramic switch need replacing. First idea was to move the transformer from the second one to the good looking one but there are a lot of wires to identify, all of them white, not so easy. Having the Roetest I gave up repairing/restoring them thinking to sell parts from them. If someone interested PM me. Also I have few versions of schematics, documentation, cards found online in time and 1 or 2 original user manuals that I can scan. And 2 complete set of tubes that I think I won't ever use.
In time I used L3-3 testing thousands of tubes and I repaired few so I have some experience.
