[thinktreasure]

If it is like the 46-350, there is a rod coming out of the back of the chassis on the right side as you view it from the rear.  A spring holds it in the "out" position, which automatically moves the switch for AC operation.  Push the rod in, and it is set for DC operation.

There is a spring-loaded bracket attached to the side of the lid on the back of the cabinet.  If you shut the lid with the AC line cord folded up inside the radio, that spring-loaded bracket pushes the rod in, connects the battery to the radio and disconnects both the AC line and the rectifier.

To operate on AC, you open the lid, which causes the rod to spring to the AC position.  Then you swivel that bracket up by hand, and as it moves, a tab uncovers a slot on the side of the lid, just below that bracket.  You run the AC line cord through that slot, and the cord itself holds the bracket up when you close the lid, so that the bracket misses the rod, leaving it in the AC position.

Back open -- automatically set to AC.
Back closed with cord entirely inside the radio -- automatically set for battery operation.
Back closed with cord in the slot -- automatically set to AC.

Don't ever push that rod in or let it out when the radio is plugged in and turned on.  If you do you will instantly burn out the filament in the output tube.  Don't ask me how I know this.  Always turn the radio off and unplug the AC cord before switching between AC and battery power.

It does not appear to be setup as you described.

I will upload some pix...

Here is the cap, the switch setup and back

Could it be something to do with the cord itself?


I figured out the battery switching.

As you see in the first photos, it's tough to figure this out, looking at it from the back of the radio

Once the chassis was out and the 1U5 and shield were removed a label on Z301 if can was visible.

The idea is simple, normally the radio defaults to AC operation.
But if you take the ac cord plug, and press that bracket down it reveals 2 slits that match the plug.
You plug the end of the cord in to keep it in Battery op.

See photo