False "low toner" messages

[BryanHiggins]

My LaserJet 5000 has started issuing continuous "low toner" messages, even with a new cartridge. What causes this, and how can I get rid of it?

[Big Al]

The toner powder has a small amount of magnetic iron oxide in it. This oxide conducts a small amount of current which tells the printer that there is still sufficient toner to print. If one of the toner cartridge contacts in the printer is corroded or bent then the current is not conducted and the printer thinks the cartridge is empty. It has been some years since I worked on one of these. If a coating of toner powder gets on the contacts that can do this.

Al

[BryanHiggins]

I found metal contacts in the printer which connect with metal plates on the cartridge. Cleaning them with fine sandpaper didn't work, though--I still get the messages. Any other ideas?

[Big Al]

Just guessing now but sometimes strange problems go away after reseating everything. Turn it off but leave it plugged in to ground the printer. Start by reseating everything connected to the formatter. It could also be one of the other boards. Any chance you could get another one to swap parts with?

Al

[BryanHiggins]

Probably not, but I'll try reseating things. It's time to blow the dust out of it anyway. Thanks for your replies.

[redcow]

The toner sensor has a signal 'ANT' which ends up on the CPU on the DC Controller.
Change it.(RG5-3517-000CN)