Hi I have a CRT radiotron tube with a fluorescent screen that's been used for electron beam deflection demonstrations in the past. There are four pins and one anode at the top of the tube.(Rated 6.3 V for cathode heating and 500 V max) Haven't been able to get it to operate. Suspect it may be blown, but I wouldn't mind locating any literature on the deflecting electron beam demo with magnet, mainly to get the wiring of the pins right. I do get the glow from the heating of the element at 6.3 V. My power supply also provides 300 V. Is the 300V enough to supply a PD for the beam to flow when the "tron"is rated at 500V max across that gap.

Any comments? Any literature? Thanks in advance

Hi.

Do not know about your radiotron CRT , but I may be of help. Is there a particular number for such tube?

----> Look trough the glass to the connections of the four pins, the filament should be entering into the center of a small metal tube, and you already identified them as it glows.

The other two may be cathode, a connection to the small metal tube. The last may be a grid, there is a chance you can see trough the glass the actual grid of ultrafine wire.

Applying 300V instead of the full rated 500V should produce some indication of the tube being functional. I do not know what you mean with PD.

Miguel

Thanks Miguel. PD means potential difference to me i.e. voltage.

I will access my radiotron wednesday; i'll look then.

I was told CRT's wear out, but don't know if it's phosphors, or maybe gas?