LJ m402n Supply Memory Error - not toner

[RandyP1234]

This is about the third or fourth m402 in our office with this issue. We suddenly get a supply memory error and it will not go away. We've tried swapping toner, firmware update, factory reset. Two of them were still under warranty and after talking with HP they replaced the units. Others were out of warranty so we replaced them. Does anyone know what's wrong with these models that this keeps happening? 

Thanks.

[Repairatrooper]

Are you using OEM or remanufactured cartridges? 3rd party cartridges are notorious for causing these issues. The only other problem we have seen and rarely on this model is the e-reader that reads the chips fails or gets broken off. It is a spring loaded contact located in the top of the cartridge cavity

[RandyP1234]

Repairtrooper - Yes, OEM cartridges. I'd agree with your suggestion about the chip reader if it were just one. But it seems odd that this would be the case on three or four of them. I also looked as best as I could at the reader connection on a known good printer and didn't see anything that obviously looked different.

Randy

[Valsimot]

I had a few of those, fixed them replacing DC controller.

[RandyP1234]

The more I think about this, I realise that all f the people that this has happened to are also people that print check frequently so they're regurlarly swapping between regular and MICR toner. I wonder if the mittle chip reader part is just wearing out?