Blinking 'Check Collector Cell' light

Which model XL series do you have? There is obviously something shorted or arcing on the plates of the cell. look at the plates and see if they are laying flat and the wires are all still attached across the front of the cell. A loose, sagging, broken or bad contact on the end plates will cause the bad cell lights. clean off the area where the cell makes contact inside the unit. The metal strips that run across the ends of the cell make contact with the plates inside the cell and get their power from them, dirty contacts in any part of these contacts will cause the problem. Even a bad contact from the end cap to the plates inside the cell will cause this. Try wiggling the cell around, kind of push on it on edge to get the plates to shift slightly and clean the points where the plates touch the outer strips on the sides. Check for arcing with the lights turned off,

Hold down button and let go after 3 to 5 seconds and let go. Might take second for light to go out. Repeat it light does go out

I had the same issue with my Oreck XL... blinking light after cleaning... I had also purchased the spray can of Oreck cell cleaner. Basically after the first cleaning it blinked... I cleaned it a second time one letting the spray foam sit and work, about ten minutes... rinsed the Truman cell off well, let it dry overnight and it now works well. Remember to reset the light by holding in the left button after start up....it was very dirty and needed that second cleaning!