This is one of the 4 so-called removable sections under the chassis.
This is the HF osc. It is the section closest to the front of the radio.
The tube is V4, an 6SA7.
Page: /Original_radios/4th_158915/Chassis_inside/Osc_module/4th_radio_inside_osc.shtml
Last modified: Saturday, 25 Apr 2026