• 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.

EM34 connection

What you are looking at is the tube pins end .


Those signal strength display tubes use "cathode rays " to display the green display at the top end usually facing the front of a radio .


Its an IO8 pin base with the locating spigot of the tube between pins =
1&8.


Standard base practice usually shows -starting from the left =
pin 1 round to pin 8 in a clockwise direction .


Direction of cathode screen support shows the angle and direction of the metal support bracket so that the display is shown at the correct angle --- I have replaced many of those types in old tube radios.
 
Last edited:
Tube equivalent books show "bottom view " its an international electronic standard .


This relates back to the early days of tube radio where a haphazard and unconventional ,maker orientated view was taken .


This caused many problems when replacing with another companies tube ,especially as tubes were dear in those day in relation to the cost of living so agreement was reached on a universal system .


Some still bucked this and some early old tubes from certain countries ran from right to left -up to down in different numbering sequences , so if you are repairing a very old tube radio be careful.