HP 7740 carriage cannot move

[ckwckw02]

 

My printer stopped working after moving house. I still don't know the exact reason even though I have been researching it for over a week. I will explain it in detail below.

Initially the printer can only print “Extended self test". Submissions submitted by computer and scanner have no response at all. Ordinary printers only feed paper but do not print.

Later, when I opened the printer to check inside, I found no major problems. Then the printer kept showing that the printer slide frame was stuck （Carriage Jam). Nothing like this has been done before.At this time, the print head of the printer will move left and right (return to the origin) very quickly （as shown in photos link）.

After that, I judged that it might be a problem with the print head's sliding frame and cable arrangement. After replacing the accessories, the problem remained the same. I'm sure there is nothing wrong with the photoelectric sensor of the print head.

Recently I discovered that if I press the gear transmission of the cleaning part, the cleaning platform will move and the printer will have a new status. The printer prompted a paper jam. （as shown in photos link）

At present, I have no progress in repairing this printer. I hope engineer with similar experience can give me some suggestions and actions to take.

[Raj_05]

Hi @ckwckw02,

Welcome to HP Support Community.

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

It seems that your HP OfficeJet Pro 7740 printer is experiencing multiple issues that could be related to its carriage, printhead, and possibly its sensor systems. Here are some steps you can follow to troubleshoot and possibly fix the issues.

Check for Obstructions and Clean the Printer

• Turn off the printer and unplug it from the power source.
• Open the printer and carefully inspect the carriage area. Look for any obstructions like paper jams, debris, or loose parts that could be causing the carriage to jam.
• Clean the printer thoroughly, especially around the carriage and printhead areas. Use a lint-free cloth and avoid touching the printhead nozzles and electrical contacts.

Reset the Printer

• Turn off the printer and unplug it from the power source.
• Wait for at least 60 seconds, then plug the printer back in and turn it on.
• Check if the issue persists after the reset.

Check the Carriage and Printhead

• Manually move the carriage from side to side to ensure it moves smoothly and without resistance.
• Inspect the printhead and carriage track for any visible signs of damage or misalignment.
• If you replaced the carriage or printhead, ensure that they are installed correctly and securely.

Examine the Encoder Strip

• The encoder strip is a thin, transparent strip behind the carriage that the printer uses to determine the position of the printhead.
• Clean the encoder strip carefully with a soft, lint-free cloth. Be gentle to avoid damaging it.
• Ensure the encoder strip is not loose and is properly aligned.

Check the Gears and Cleaning Station

• Inspect the gears and cleaning station. Sometimes, misaligned or broken gears can cause the carriage to jam.
• If pressing the gear transmission of the cleaning part changes the printer status, there might be an issue with the cleaning station mechanism.
• Ensure the cleaning station moves freely and is not blocked.

Check the Printer Firmware

• Ensure that your printer firmware is up to date. Sometimes, firmware updates can fix bugs and issues related to printer hardware and sensors.
• You can check for firmware updates through the printer's control panel or the HP website.

I hope this helps.

Take care and have a good day.

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Alden4

HP Support