Hi WillysUncle,
Please reset default program for the Ranger robot with latest version mBlock 3.4.6refer to this document.How to Reset default program for Ranger.zip (411.1 KB)
Then please connect its Bluetooth to latest version Makeblock APP, open the Nervous board project on the panel and check if it works properly.
Besides, what’s kind of batteries do you use? According to our test and research, it is suggested to use rechargeable Li-ion battery or rechargeable nickel-metal hydride, nickel-cadmium which can be bought from amazon or local shop. Or Alkaline battery with good quality like Energizer, DURACELL.
Once still the same issue after you tried above, please kindly help take a video to show the behaves on the nervous bird while you controlling it.