m479 won't print color, anybody have schematics?

[doc538]

Printer stopped printing colors, black is light. Have changed all boards except the low voltage board. replaced cartridges, transfer belt, checked electrical connectors but with a schematic and test point references I can't trace the problem. HELP PLEASE.

[Raj_05]

Hi @doc538,

Welcome to HP Support Community.

Thank you for posting your query, I will be glad to help you.

If your HP M479 printer has stopped printing colors and you've already replaced cartridges, the transfer belt, and checked connectors, but still face issues, here are a few additional troubleshooting steps to consider.

• Check the Color Imaging Drum: Even though you’ve replaced cartridges, the imaging drum can also affect color printing. Inspect it for any signs of damage or contamination.
• Clean the Printhead: Sometimes, the issue can be related to a clogged printhead. Run the printer’s cleaning utility or manually clean the printhead if applicable.
• Inspect the Low Voltage Power Supply: Since you haven’t replaced the low voltage board yet, it might be worth checking. A faulty low voltage board can cause inconsistent color output.
• Firmware Update: Ensure your printer firmware is up to date. Firmware updates can fix bugs or issues related to printing functions.
• Check the Print Settings: Make sure the printer settings on your computer are not set to print in grayscale or black and white only.
• Run Diagnostics: Use the built-in diagnostic tools of the printer. Some models have self-test pages or diagnostics that might pinpoint the issue.

I hope this helps.

Take care and have a good day.

Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping!

Alden4

HP Support 

[doc538]

Hello Alden4,

Interesting suggestions! What is a Color Imaging Drum? First time in 40+ years that I have heard of one in a HP Printer, Firmware update is  good suggestion and was done already as were diagnostics, cleanings, color calibrations Etc.

Print head cleaning was impossible due to the machines not having one!

Low voltage supply is arriving today. It is pathetic that point to point wiring diagrams with voltage checks are NOT available, there is nothing in my SERVICE manual.

I am an old School tech, I have a volt meter and O scope and know how to use them but without schematics, they are useless and I have to become a low level parts changer!

Thanks for trying

[Raj_05]

Hi @doc538,

Thank you for your response, 

I'm sending a private message to assist you with the next action.

Please check your Private message icon on the upper right corner of your HP Community profile Next, to your profile Name, you should see a little blue envelope, please click on it or simply click on this link.

I hope this helps! Keep me posted.

Alden4

HP Support 

[doc538]

well, I changed out the low voltage PS and it did not correct the current problem of no color and faded blacks. Guess I will have to throw this printer out!