I'm using my 18SZ radio to train a young student who has a 9CAP.
just when my 18SZ is with full battery (newly charged) the student radio works. Few flights after radio 9CAP starts to beeping and does not command anything else. Until the function menu of the 18Sz is no longer obeyed when I activate the training key (it always goes off).
these radios are not compatible? battery voltage problem (6.6V versus 9.6V of the 9Cap?). Any solution?

regards.