My minolta dialta copier has a c-of24 error code,

This code deals with the AIDC or Automatic Image Density Control failure. Most always this code is caused by toner collecting on top of the sensor. If you happen to know how to remove the Imaging Unit and then the Drum from the Imaging Unit then you could clean the sensor yourself. If not then I would recommend you call a service technician to correct the problem.
Basically what is happening is there is a thin mylar seal called the anti-spill mylar which is suppose to keep the toner off of the sensor. But these start to fail over time and allow toner to drop down onto the sensor which results in false readings and the C0F24 code. The mylar must either be replaced or what I do as a field fix is to reform the mylar back to it's like new shape so it seals. Then clean the sensor area of toner then re-install the drum and imaging unit back into the machine.
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