JBF4 is a great FC. I have a few. If I am buying a new FC, I would go with F7.

Nothing wrong with your lipo size. Both 4S and 6S are fine.

(Do you try diffrent batterys? i had bad batterys which do sush a problem)

Sorry for the long delay, , but it’s took me a few days to get the time to swap the FC.

Soooo, I put the flight I troller into another quad with a 35amp esc (4s) and it worked perfectly.. you tell me, I’m sorta lost.

My only thought is that it must be the esc that is causing the first quad to shut down. Any thoughts?

Yeah I tried a couple batteries- 4s 100c 1500mah & a 1000mah 100c 6s. None are bran new but, they all work in my other quad and charge fine.

So either ESC or motors. You will need a Blackbox log to start troubleshooting.

Maybe it's a bad solder joint on the power leads?
Can you throw in a picture of those just to be sure?

If you have a multimeter, test the esc's for continuity (). And maybe also the fc. Also check for any excess heat on the chips.

I had the exact same issue with a Omnibus F4 pro V3. It turns out to be the PWM on motor 2 was failing. Possible board issue or the internal damage in MCU possibly ESD related.

(when i read again, i tought about „flayaway“ prevention, would this be visable in the log?
test on the bench and conect it to bf „while you cant arm again, at the moment it would need lipo plug out/in“ would display as arming flag.)