C901 Magenta OEM toner undetectable

[Discount Printing Service]

I have an issue with a production model C901. Machine stated replace Magenta toner while running job. Operator pulled out the cartridge to replace but it was 3/4 or more full. No SC codes thrown. Re-installed same cartridge and under the remaining toner menu it stated magenta was undetectable. Main screen message shows "Independent-supplier toner cartridge is set" yet this is OEM toner. Installed new magenta cartridge still not being recognized and same "independent-supplier toner cartridge is set". Checked toner supply tube for obstructions found none. Still no SC codes thrown. Ran manual execute on magenta motors in SP mode, motors are working correctly. Searched through the service manual and all my RTBs as well as did a search online and can't find anything on this except this for a SP3600:

“Independent-supply toner”

Independent-supply toner is set.

Use the toner recommended for this printer.

Waiting for call back from Ricoh Express Support engineer but I believe this is a defective chip on the magenta cartridges, however, the two cartridges were shipped at different times but it could still be the issue. The dealer the cartridges came from are sending new chips as they mentioned having this problem with a c7xxx series cartridges as well. Anyone had a similar issue and what was the solution?

[slimslob]

Re: C901 Magenta OEM toner undetectable

Do you know if it showed a toner low message for a number of copies and then went to toner out or did it go immediately to toner out. I not sure about the C901 but larger model will go to toner out if the toner nozzle clogs resulting in no toner passing through the toner out sensor.

[anothertech]

Re: C901 Magenta OEM toner undetectable

If you are sure the toner supply tube is not blocked, the problem may be the sub hopper pump. Remove the sub hopper and look inside to see if it's full or not. I always replace the entire sub hopper but you can get the parts to rebuild it if you choose to.

[Discount Printing Service]

Re: C901 Magenta OEM toner undetectable

Do you know if it showed a toner low message for a number of copies and then went to toner out or did it go immediately to toner out. I not sure about the C901 but larger model will go to toner out if the toner nozzle clogs resulting in no toner passing through the toner out sensor.

Not 100% sure but I believe there was a low magenta toner or a low % indicated before it went to toner out but then again I could be wrong on that. I did check the nozzle and toner was moving through it to the tube but I will check it again.