Tube Testing & Repair Hints

Nowadays it isn´t easy to perform accurate, in the meaning of time varying voltages, measurements, because in the lack of suitable and affordable test gear. At the surplus markets you could get lot of tube-testers, which means you apply a static voltages and then read a plate current on an antique ammeter. Mostly the testers come with an incredible amount and types of sockets you never need.
In my point of view it is more convenient to have only one tester, but suitable for nearly all components that comes with a scope: resistors, vdr´s, diodes, tunnel diodes (..!), backward- , snap-off-diodes and not to forget zeners. Certainly you need to check all active devices like transistors (germanium, silicon) and *tubes*.
The last industry-proven tube tester was the Tek 570 Electron-Tube-Curve Tracer.
This device plots all important characteristics on a 5-inch crt like plate current against plate voltage, with the grid as parameter and others. The 570 had in addition a built-in  voltmeter and was capable to hold and measure two tubes to match them...

A year ago I had the opportunity to buy a modern Tek 577 Curve Tracer with the storage capability. I have only the adaptors for diodes and small-signal transistors. After recalibration the 577 shows very good results. I like especially the storage capablility so you can verifiy old “temperature compensated zeners”. (Please don´t think in this case at LTC burried-zener)