I've got the same problem but its not 3 beeps with the Li-Po it should be 4 (one long low beep followed by 3 shorter beeps indicating
a 3 call Li-Po) Only mine doesn't make the third short beep, doesn't go into programing mode, arm the motor or anything. I've tried
trim and end point adjustment as well as reversing on the transmitter with no luck. Battery check showed 11.73v. I've tried another receiver with no luck. A replacement ESC was sent and it does the same thing. Motor never arms. Servos work with battery connected but thats all I can get to work. This is the Plug & Play and has not had the motor turn over the first time since it came out of the box. From what I'm seeing posted and what I'm experiencing, the electronic components in this bird are really inferior poor quality and junk. The aparent lack of quality control in its manufacture is uncalled for. Never in almost 30 years of RC flying have I run into this much of a problem. There is albsolutely no excuse for not living up to its claims. Horizon was good in responding and sending a replacement ESC but it hasn't corrected the problem. They must be used to hearing this problem. You would think park-zone would atleast hook up a battery and receiver to check out its operation before shipping to Horizon. Unless I can do something to correct the problem I will probably send the plane, Li-Po, spare parts etc., etc. back for a refund. This may cause me to reconsider the purchase of a JR 10X later this year.