Our Panasonic UF-790 fax maching continues to issue the error Check Cassette Error Code 0011 even after replacing with a new cartridge.

There is a fix for this. But only a Panasonic tech has access to the parts for the fix. The toner sensor underneath must be moved closer to the cartridge, you are not low on toner.

UG-5510 cartridge has drum and toner in one unit.

its a receiving error code means a computer was trying to fax you and it didnt connect properly

The small tip on the left side of the paper cassette is broken off.

wad up a small piece of electrical tape up and stick it into the black u-shaped sensor hole where the tip used to go in.

That code is for a bad LASER unit.

Try a new toner cartridge first.

If a new toner cartridge doesn't take care of it, replace the fuser.

It could be a refilled Kyocera KM-F650 cartridge in a Panasonic UG-5510 box.

They look identical, but are configured differently.

You need to try another cartridge as it appears it is not a machine problem.

you broke the tab on the back of the paper cassette. if you look in where the cassette goes on the back left you will see a hole with a sensor that looks kinda like a upside down letter U . put paper inbetween the sensor and the machine should say out of paper and put the cassette back and you should be fine

Where is the broken left tab. Sometimes on that cassette the tab breaks that tells the unit that the paper cassette is installed. If this is the case then the tray has to be replaced.

Check cassette refers to the paper cassette. If there is no paper or the cassette is not seated correctly, then you will get that error. If you tried those, then check the left rear of the cassette for a tab. If that tab is broken off you will get this error and you need a new paper cassette. Good luck.