Minion down

Hi, with my Minion I am still a apprentice. Yesterday in the evening I get the fault "verify heater bed ......". Bed stays cold. Today I opened the box (not powered). I disconnected the heatbed wires and measures the electric resistance. It started (my meter tells me MOhm) at 28 and go down to no connect (o/l) during 5 to 8 seconds. Then it start again at 28 (roundabout) and counts back.
Next I give power to the box. There was no power on the clamps. I set the temp to 50 degrees in mainsail and I get 22 volt.
So I thing the Bigtreetech octopus is working right?
Any advice?