Help with 3 6040's + controllers?

[LightingBug]

I have 3 of these, 2 in one tank and one in another.

1 of them stopped working (the 2 in the one tank) a few days ago, the other just a few hours ago.
They all flash/blink the top 2 dials and the orange light for the external control setting.

I know this cannot be defectives as the odds of all 3 being bad would be slim.

Any advice on how to get them working?

 

[LightingBug]

Disregard, they just needed a little TLC.

 

[rvitko]

OK, I was going to say cleaning is often a culprit and it is critical that at least every 6 months they are disassembled so the drive unit is out of the motor and soaked for some hours in 50/50 vinegar and water to descale the pumps.

 

[LightingBug]

I should have done that before posting, but they have only been in use for a few weeks.