OfficeJet 6978 suddenly began printing stripes

[ironhammer]

My OfficeJet 6978 suddenly began printing stripes in a blue areas.  It happens with both copying (with the computer cable disconnected) and printing from computer.  The diagnostic page has horizontal yellow stripes  through test pattern #3 which is supposed to be all green.  The printer has standard white paper and all new genuine HP cartridges.   I have done all the steps: cleaned the printheads multiple times, aligned the printheads multiple times, hard restart (twice).  Thinking it was a defective blue cartridge, I bought another.  Same result.  I am using a Mac desktop computer but it doesn't matter since it happens when I copy with the cable disconnected.  I am out of  ideas unless it's a printer failure.

[TEJ1602]

@ironhammer, Welcome to HP Support Community!

If you have already performed the steps from the document Black or Color Ink Not Printing, Other Print Quality Issues and the issue persists, it could be a hardware failure.

Please reach out to the HP Support in your region regarding the service options for your printer.

Hope this helps!

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