• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

GU-50 Tube

Is the GU-50 (ry-50) listed in the documentation, can your valve tester produce 800volts for the Anode at 150mA and 250volts for the G2?
Has it got the correct valve base to fit the GU-50 probably not.
I doubt it will give even a rough idea. Like most "valve testers", they do not test at the correct voltages.
Unless of course you are talking about the British GU50 which is a mercury vapour half wave rectifier. It probably can test that for you.
 

Attachments

  • Screenshot 2024-12-27 at 07.49.26.png
    Screenshot 2024-12-27 at 07.49.26.png
    748.6 KB · Views: 49
  • Screenshot 2024-12-27 at 07.46.51.png
    Screenshot 2024-12-27 at 07.46.51.png
    916.8 KB · Views: 52