[glyphmon]

Arran,

I have had enough dealings with the band switch in my 37-620 that I have no desire to do so here.

My thought was either a rear-chassis or cabinet-mounted switch solution that in addition to controlling which signal progressed to audio output (like the jumper at the terminal on the back) would also power to the RF section such that it neither, first and foremost, uses up component life in the RF section, nor power if it should sit there and play audio only through the aux port for days.  If it's carrying power very far, especially in parallel with signal between said switch and the output section of the radio, I suspect there might need to be some shielded wire used.  Again, this is all hypothetical at this point.

And while we're on hypotheticals...  
Beside a USB wall adapter, does anyone have thoughts about how to power a USB-connected device inside a radio?  This is the Bluetooth receiver I use for streaming to the AM transmitter for now: https://www.amazon.com/dp/B0F1FHV54W
It gets its power from the aforementioned wall adapter, but I'm wondering if there might be some way to power it via the radio's own internal supply.  It's USB 2.0, which, if I read correctly provides 5V at a maximum of 500 mA.  Since the wall warts and I'm sure their ilk in USB chargers don't play nice with radios, it would be ideal to have something built in and less likely to cause interference.

Keeping period-appropriate is a nice target and is certainly my goal from the traditionally visible faces, but not a requirement when seen from the rear of the case.

Back to troubleshooting in a few minutes.

Best wishes,
Roy