I have the same problem (flashing LEDs). Unfortunately, I am not technically minded and would not try to repair myself if necessary.
We are on a farm in the Karoo. Over the last 6 months or so this happens if there is a "power-down" for some reason. Say failing batteries. In the past, it would take a day or so before the batteries would fully charge and then mysteriously with on-and-off switching it would start working again.
We recently replaced the gel batteries with a Li unit. Same flashing LEDs until the unit was fully charged. Then it still took 4 - 6 hours before I got it operational again.
Three weeks later and the unit was making a strange light grinding sound. I powered down and then on again - the fast flashing problem was back and persisted for 3 hours yesterday. I powered up this morning and 4 hours later still no joy.
Any help will be most appreciated.