The schematic does not show a capacitor on pin DEC1 of nRF51822. Nordic's reference schematics show a decoupling capacitor on that pin. It decouples the chip's internal 1.2V bus. See the Nordic nrf51 reference manual, page 42. Is there a reason you omitted that capacitor? I don't know, maybe it is optional. (My problem is one of power on reset with low voltage directly to RB Nano pin Vdd. Probably my problem is unrelated.)
Also, exactly which package and revision of the nRF51 is used? (The shield prevents anyone from reading the part numbers of the nRF51.)
The schematic does not show a capacitor on pin DEC1 of nRF51822. Nordic's reference schematics show a decoupling capacitor on that pin. It decouples the chip's internal 1.2V bus. See the Nordic nrf51 reference manual, page 42. Is there a reason you omitted that capacitor? I don't know, maybe it is optional. (My problem is one of power on reset with low voltage directly to RB Nano pin Vdd. Probably my problem is unrelated.)
Also, exactly which package and revision of the nRF51 is used? (The shield prevents anyone from reading the part numbers of the nRF51.)