My guess..
The vibrator is the large cylindrical can with the clips. The vibrator chops the +6 volt DC power (to simulate AC power) and runs ir thru the trsnsformer to step it up to approximately 150 volt AC (APPROXIMATELY) which is rectified by the 6X4 tube to DC to operate the rest of the radio circuits. I'm guessing the rest of the tubes are: 6BE6 converter, s 6BA6 amplifier followed by a 6AV6 audio amplifier and detector and a 6AQ5 audio output . Later there were 12 volt tubes developed to operate on 12 volts without having to raise the operting voltage to 150 VDC. The older 6 volt radios used a vibrator and a cold cathode rectifier tube, an 0Z4G and other 6 volt tubes. In another lifetime, I used to fix TUBE TYPE RADIO AND TV SETS, and had all the testers and equipment. AM radios are easy to fix.
Cheers,
Bob Renton