Working with technology is with hardware, software and application. So I have this issue were I can assist with someone printer. It's still under warranty and this individual just brought three packs of toner and it's not compatible with his printer. So with experience is always check your part no# before you purchase the part. If it doesn't work then because it's not compatible then do not force it to work. That's the reason for STANDARDS on parts made by IEEE.  Going and telling me its the circuity connection is not the reason! This is were I stand on the issue and which brings me to the morals truth, when ordering the part double check the shipper product just because it say's HP it might not work. Like in this cast.