I have a Brother MFC-J480DW using refillable cartridges for about 5 years with no problems.  Today after printing a one page document, the printer quit recognizing the yellow cartridge.  Tried re-installing several times with no success.  Cleaned the chip contacts and tried again with same result.  Did a power reset of machine... problem continues.  I am ordering a set of compatible cartridges to try that in case the chip on the yellow cartridge has gone bad.  Any suggestions I haven't thought of?  Can I get at the contacts inside the machine?  I doubt the problem is there as the failure mode happened while printing and not while inserting cartridge following refill.