KM 250ci. Wrong toner fitted.

[fotocom]

We have a KM 250ci in the field , a service call was logged for same after a few thousand copies (the machine is almost new), the machine was looking for cyan toner.
On arrival it was discovered that Utax toner had been fitted to the machine, in error by the customer. The toners are not compatabile and as a result of this the toner coupling mechanism at the rear of the machine was discovered damaged.
This mechanism and motor was replaced, the following are the problems experienced and the work that has been carried out to date:
1. Toner supply unit fitted.
2. Machine now not recognizing the cyan toner cartridge.
3. RF pwb replaced, machine now recognizing cyan toner. Machine fully tested after a few hundred copies machine errors add cyan toner again.
4. Cyan developer unit complete (new) fitted.
5. Machine back up and running, however after 500 color copies machine errors add cyan toner again.
So to date: new toner supply unit, new developer tank, new toner, up todate firmware.
I have attached a diagram of the system.
Any ideas ???
20110527100700055.pdf

[Zackuth]

Have you looked at the area where the toner gets deposited into the developer? That Utax toner might have clogged something.

[fotocom]

That area checks out fine. I have fitted a brand new Developer tank.

[blackcat4866]

What U131 readings are you getting? =^..^=