I'm a repair tech at a company that sets up concerts, events etc.
I see some posts kind of similar, but not quite.
Our Fat Frog lights up briefly & won't start, no lcd display, intermittently.
I plug it in, all the leds and lights flash on briefly, then go off.
Most of the time it will work. One time it got stuck loading at 44% and froze.
I tried tightening all the connectors, and cleaning the contacts on the memory cards,
Since it is so random, I don't know if it helped yet, but any feedback would be appreciated