I recently purchased some SER 5 5560U mini PCs.
All three of them have had an issue or more since day one.
And yesterday - I came home to find one basically dead - the power light is on, the fan is on - but no other responses beyond that.
The original issues were,
they wouldn't boot upon first plug in. I had to reset them (remember the reset button? - yeah they have one). They finally did come up.
Update BIOS/UEFI was a huge pain finding their updates
list itemwireless keyboard didn't work when plugged into the front USB ports - this turns out to be that on these machines, USB 3 has so much radiation coming off them, it interferes with wireless keyboard/mice - the recommended solution - buy and use a six in USB extender.
USB ports are mounted upside down - come on - USB isn't new - no excuses here!
I troubleshot the now basically dead machine:
I long pressed the power button - nothing, I head the button for 30 seconds - nothing.
I pulled the power, pressed the power button 15 times (to drain the capacitors) plugged it back in - pressed the power button, lights came on - fan is spinning - no beeps, no video.
I removed power again - i held the reset switch for 15 seconds, plugged it back in - it instantly powered on - again, fan spins, no video.
I disassembled the device, unplugged the BIOS battery, left it unplugged for 10 mins, the pressed the power button 15 times, held the rest button down for 10 seconds, then reassembled it, plugged in power - it instantly gave the power light and fan spin - no video.
I removed power, I removed the RAM and the M.2 SSD, plugged it back in - instant power, fan spin - no video no beeps.
The only signs of life in this unit are power light and spinning fan, but nothing else I've tried has brought this unit back to life.
There are no additional troubleshooting tips I can think of.
I recommend staying away from these, if for no other reason than their website for drivers is bad.