Thanks EarthKmTech. Will check for IU issues etc. when we go out tomorrow.
NOTE: the first time went out. A school IT person said a teacher had tried to reseat the waste toner and somehow got the cover of the black IU/DV unit that sticks into right side of waste toner off. He had refitted it and said he cleaned up a little developer spill. When we were there that first time it did appear OK and that is when we first hand emptied the clog and it ran for quite sometime.
However, this may be a clue that you have brought up.
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