Equipment involved: Spectrum Dx7s and two Orange Rx615 receivers.
No. 1 Rx 40 plus flights. No. 2 Rx second flight. The 2 Rx's did the same thing with the only difference being the amount of use. On both occasions at the field the Rx's would not light up or turn on at the beginning of the day. Checked voltage with a multimeter from battery and it was 5 volts. On the bench removed the Rx's and installed new Rx's and before plugging battery to new Rx's plugged battery power into old ones & both lite up. Both new Rx's flue normally. Have not checked old Rx's as there is something wrong. What could be the problem and is there a chance I could use them in a small foamy. I haven't heard of something similar to this.