Epson L1800 0AH and 71H Errors, Carriage Problems, and No Power After Waste Ink Pump Replacement

Question:
I have an Epson L1800 using RIP V10.1. It started with cyan and magenta inks blending into each other during printing, and then the print carriage began acting up. I replaced the cables because I thought that was causing the issue, and I also cleaned the ink tanks and refilled them with new ink. I feel like I have seen this problem before, but I cannot remember how I solved it. After replacing the waste ink pump, the printer now will not power on from the front button. When I press the power button, I hear a faint sound from the left side of the printer, but there is no light and no startup. Before I changed the waste ink pump, I was getting red blinking lights, and the errors were 0AH and then 71H. I really need help because I am out of ideas.

Answer:

From what you described, you are most likely dealing with several separate issues rather than one single fault. The RIP software is probably not the root cause here. RIP V10.1 may affect print workflow, but the symptoms you listed point much more strongly to mechanical, sensor, carriage, APG, or power-related hardware faults inside the printer.

The first issue was the cyan and magenta merging into each other. When colors blend together like that, one possible cause is a printhead problem, especially internal delamination or internal ink leakage inside the head. In some cases, a partially damaged printhead may still print under light use but fail under more demanding printing conditions. Another possibility is contamination in the ink path, cross-contamination during refilling, or pressure imbalance in the ink delivery system. Since you also cleaned the tanks and changed ink, it is possible the original color-mixing symptom was in the ink system, but it is also very possible that the printhead itself had already started to fail.

Then came the 0AH error. On the Epson L1800, 0AH is commonly associated with carriage movement or carriage initialization trouble. In practice, that often means the printer cannot correctly read or complete the carriage startup movement. Common causes include a dirty or damaged CR encoder strip, carriage drag or overload, timing belt issues, carriage rail resistance, ink tube snagging, incorrect platen height, improper printer assembly, or a problem with how the capping station was installed. If anything physically resists carriage travel, the printer may throw 0AH during startup.

So if you had a carriage that was not working correctly, 0AH fits that symptom very well. Even if the cable replacement seemed logical at the time, changing cables does not always solve a carriage initialization problem if the real cause is mechanical drag, a dirty encoder strip, belt tension trouble, or interference from tubing or station alignment.

After that, you mentioned the 71H error. That is a very important clue. On this printer platform, 71H usually points to an APG home position seeking error. In simple terms, the APG system is not finding its expected home position correctly. This is often caused by a misaligned APG unit, a disturbed or damaged APG sensor, debris blocking the sensor, a loose connector, or a cable that is not seated properly. Since you mentioned that you changed the waste ink pump, that lines up very closely with the timing of the 71H error. Work in that area can easily disturb nearby APG-related parts, sensor flags, cable routing, or mounting positions.

So the sequence makes sense like this:

First, there may have been an original carriage or encoder-related issue causing 0AH.
Then, after working around the waste ink pump or nearby assemblies, the APG area may have been disturbed, causing 71H.
Now, after reassembly, the printer no longer powers on properly from the front panel, which suggests an additional power-path or board-level issue.

Your current symptom, where pressing the power button causes only a faint sound from the left side but no power light and no full startup, is usually no longer just a carriage issue. At that point, I would start thinking about a power supply problem, mainboard problem, shorted cable or assembly, blown fuse, or front panel connection problem.

On an L1800 that appears dead from the control panel, the most important items to inspect are:

• the panel FFC cable

• the panel board itself

• the power supply connection to the main board

• fuse F1 on the power supply board

• any short created during reassembly

• any pinched or misrouted cable after the pump replacement

• any disconnected connector around the pump, APG, carriage path, or mainboard area

A completely dead front control panel often means the printer is not getting proper low-voltage logic power, or the mainboard is not distributing it correctly. In some cases, a shorted peripheral assembly can pull the board down and prevent startup. In others, the power supply may be partially responding, which could explain the faint sound, but the machine never fully boots because the board is blocked by a fault.

It is also important to separate the printer itself from the ink system. Many converted L1800-based DTF systems are really a combination of the base printer plus an external or modified ink system. That ink system may include a mixer stirrer, white ink circulation, a heater, or a vacuum platform. The rear master power switch can feed both systems, but the actual printer startup depends on the printer's own boards and internal electronics. That is why sometimes users notice that the ink system or mixer still seems active while the printer itself remains completely unresponsive. When that happens, the fault is usually inside the printer body, often involving the mainboard, power board, fuse, regulator, or a shorted internal connection.

Based on everything you described, I would rank the likely fault groups this way:

First, the 0AH error was probably related to CR encoder contamination, carriage drag, timing belt issues, capping station alignment, rail resistance, or tube interference.
Second, the 71H error strongly suggests the APG home position system was disturbed, likely during or around the waste ink pump replacement.
Third, the current no-power condition most likely points to a power-board/mainboard issue, blown fuse, shorted connection, misconnected panel cable, or board damage after reassembly.

If you are checking the printer yourself, the most useful inspection points would be:

Make sure the front panel cable is fully seated and not reversed or damaged.
Check whether any connector was left unplugged during the waste ink pump replacement.
Inspect the APG area for anything misaligned, blocked, or installed one position off.
Check for pinched wires, especially where covers and brackets were reinstalled.
Inspect the CR encoder strip for ink, scratches, or displacement.
Verify the carriage can move freely by hand when the printer is off.
Check the timing belt and carriage path for drag or obstruction.
Inspect the power supply board and fuse F1 if you are qualified to do board-level inspection safely.
Disconnect suspect peripherals one at a time, when appropriate, to see whether a shorted assembly is preventing startup.

If the printer was working at least partially before the waste ink pump change and then became effectively dead afterward, that strongly increases the odds of a reassembly-related issue such as a disturbed cable, APG misalignment, short, or power-path fault.

Addressing printer issues like this can become quite complicated because so many of the problems are hands-on and mechanical in nature. For that reason, we are not able to provide remote troubleshooting, repair suggestions, or direct support for printer repairs beyond general information. We do offer an in-person evaluation and repair service through our local diagnostic facility, which you can find here: printer repair service [https://bchtechnologies.com/printer-repair-service]. Because demand is high, we work on a first-come, first-served basis, and it may take a few weeks before we are able to receive your printer for drop-off. Our service is set up to repair either an entire printer or specific parts, with clear instructions on how to proceed. That said, we understand our rates may not be the lowest, so we strongly encourage self-help research as well. A good place to start is YouTube, including our BCH Technologies YouTube homepage [https://youtube.com/@bchtechnologies]. Use the search icon next to "About" on the right side of the menu bar to look for videos on your exact issue. I get many messages every day asking whether we have covered a certain topic before, and after making videos for so many years, it is not always possible to remember every one. Searching directly on YouTube is usually the fastest approach, and it may also surface useful videos from other channels.

Thank you again for reaching out and for your continued support. We sincerely appreciate your trust in BCH Technologies, and we hope this gives you a clearer direction for diagnosing the 0AH, 71H, carriage, and no-power issues on your L1800.