It came to pass that, in the process of inserting a 7809 between the Raduino daugterboard and its B+ pin-to-mainboard, that I failed to notice a solder blob shorting out the 7809. I made a 90-degree header change at the Raduino mounting point on this build, making this relatively painless [or not].
It was realised, when turning on the (1-metre-long) remote power switch whereupon an added power relay chattered on and off [due to low relay supply voltage for the instant of the short], graciously saving my 5-amp fuse. Don't ask....
Since then, the radio powers up but the Nextion screen would not get past simply powering on and showing the basic screen graphics (as if in the PC editor). The obvious have been performed:
- Replace Nano.
- Try different brand of Nano
- Try Nextion screen from redundant uBitx radio
- Replace Raduino (in stock, known)
- Replace 5-volt regulator on oruginal Raduino.
- Swap Raduino from redundant uBitx radio
- Try swapped Raduino with different Nano
- Restore Raduino with original, 2-line LCD display (shows opening call sign and firmware edition, nothing more)
So: should not a Raduino board power up by itself when given 12v & (-) , and respond to the original LCD display or a Nextion screen, that is, respond to manual display inputs even without a mainboard present?
If a mainboard is required for Rauino/screen operation past initial lighting, what might fail specifically which will stall further brain function like that?
V3 board; whole rig seen in my Photos folder.