This is the best tube tester that was made in
Germany in the 1950s. Due to some special features they still work great:
- no electrolytic caps - only MP types are used
- tube rectification with 3 RGN 1064 tubes of SQ
- great quality overall (as Rohde + Schwarz)
My tester is from 1956 and still works perfectly.
The later model RPM 375 received some changes.
The most significant are the rectangular meters.
The RPM 370 works from 0-500 Volts for plates
and screens (the Funke tube testers do not) and from 0-100 for grid bias.
All tests are made to the original design
specifications: no "good" or "bad" tube - only absolute and comparable
Before testing a tube's emission all electrodes
are tested for infinite resistance. Then the gas can be tested as well as